London, July 10^th to 14^th 2000.

FUNDAMENTAL DIFFERENCES IN EXTERNAL SPINE GROWTH IN THE BRACHIOPODS

Fernando ALVAREZ¹ and Howard BRUNTON². ¹Department of Geology, University of Oviedo, Oviedo, Spain. (fernado@asturias.geol.uniovi.es). ²Department of Palaeontology, The Natural History Museum, London SW7 5BD, UK. (chcb@nhm.ac.uk).

This study investigates the external spines ornamenting many taxa throughout the Brachiopoda. It draws on the work of Williams and Rowell (1965), Brunton (1976), Brunton and Alvarez (1989) and Alvarez and Brunton (1991) and extends the suggestion by Brunton, Alvarez and MacKinnon (1996) that there is a significant difference between the Strophomenata and most other Rhynchonelliformea, as seen in their cardinal processes. We wish to test this difference using the growth and morphology of long, hollow external spines. We studied examples of many spinose genera, but concentrated on a linguliform siphonotretide, members of the Productida, Rhynchonellida, Athyridida, and the Spiriferinida. We find that there is a consistent difference between the spines of siphonotretids and productids as compared to the other studied examples. We describe these two forms of hollow spines respectively as 'tubular hollow' and 'sutured hollow' and comment on other external "spines". The former grew from a separated bud of generative epithelium at a valve margin which grew away rapidly from the valve surface producing a complete tube of shell; the latter grew from a portion of marginal generative epithelium which grew forward rapidly to become separated from the rest of the margin as an extended lamellose outgrowth which became rolled and fused on its commissural side to form a sutured hollow spine.

Fernando ALVAREZ¹ and Christian C. EMIG^{2 1}Departamento de Geolog’a, Universidad de Oviedo, Oviedo, Spain (fernando@asturias.geol.uniovi.es). ²Centre d'Océanologie de Marseille, Station Marine d'Endoume, Rue de la Batterie-des-Lions, 13007 Marseille, France (Emig@com.univ-mrs.fr).

The study of the brachiopods living along the coasts of the Iberian Peninsula and associated islands started in the 19th century. Brachiopod subphyla are unequally represented on these coasts, the Linguliformea only by Pelagodiscus atlanticus and the Craniiformea by Neocrania anomala, whereas the Rhynchonelliformea is represented by about 30 species (in 22 genera).

P. atlanticus, attached by a pair of muscles to hard substrates, is capable of reorientation according to the direction of surrounding water currents. N. anomala, has the ventral valve (barely calcified at times) completely cemented to a hard substrate; this valve is thicker and more irregular in the specimens occurring in the Mediterranean than those from the Atlantic Ocean. In the Rhynchonelliformea, the ‘thecideidines’ are a peculiar group because only the larvae bear a pedicle, adults being cemented. The other species are anchored or supported by different kind of pedicles and some have the ability to move in response to changes in sediment level and to prevailing water currents.

Little is known about their social behaviour. It seems that they suffer a rather low level of predation, apparently because of the small body biomass. The incidence of parasites, infections or diseases seems to be insignificant. Predators and other organisms, such as chitons, gastropods and echinoderms, disturb the brachiopod’s normal development; these seem to have induced displacement towards more cryptic situations. In these habitats, the larvae attach very closely to one another, producing dense populations of individuals, many of which are malformed. In deep waters the larvae seem to be less selective in settling onto a substrate.

Brachiopods have little pontential for defence, being vulnerable to a broad spectrum of epibiont, especially fast growing ones. Taxa with punctate shell seem to have more protection against epifaunal attachment than those without punctae, although, for example, adult Megerlia truncata and Terebratulina retusa may have numerous epibionts over their punctate shells. Perforations, probably produced by gastropods, have been observed in T. retusa and in Gryphus vitreus.

The shell, particularly the fibres of the secondary layer, come apart easily during maceration, especially in species with punctae and/or those having no prisms of tertiary layer. Because of this only a small fraction of the shells present in the initial biocoenosis is preserved.

Due to the influence of environmental factors on the shell size, calculating the longevity of brachiopods is problematic because specimens of similar length may vary in age, sexual maturity and longevity. There is thus little data on brachiopod longevity. Pelagodiscus may live between 3 and 6 years, and Neocrania about 14 months. Brachiopods initially grow quickly; this helps survive the inital most vulnerable phase of the life. Growth subsequently becomes more stable, diminishing in the latest stages. In general brachiopods seem to live between about 8 to 12 years.

Fernando ALVAREZ¹ and Christian C. EMIG^{2. 1}Departamento de Geolog’a, Universidad de Oviedo, Oviedo, Spain (fernando@asturias.geol.uniovi.es). ²Centre d'Océanologie de Marseille, Station Marine d'Endoume, Rue de la Batterie-des-Lions, 13007 Marseille, France (Emig@com.univ-mrs.fr)

With the exception of Lacazella mediterranea, all other Mediterranean species occur also in the Atlantic Ocean, although generally extending to deeper waters. In the NE Atlantic, Fallax dalliniformis, Glaciarcula spitzbergensis and Dallina parva occur only in the Gulf of Biscay. Cryptopora gnomon and Acrobelesia cooperi do not appear in the area between Finisterre Cape and Gibraltar, although the presence of Phaneropora incerta has been confirmed. P. incerta, Pajaudina atlantica and Argyrotheca grandicostata are typical species of the Mauritanian faunistic province. Some species (e.g. Dallina septigera, Hispanirhynchia cornea, Macandrevia cranium) although now unknown in the Mediterranean, seem to have lived there at the end of the Tertiary or beginning of the Quaternary. Climatic fluctuations during the Quaternary induced changes in salinity, temperature, water currents, sea level and biotopes leading to a series of species replacement between tropical-temperate and boreal faunas.

From available data on depth, brachiopods from the Luso-Iberian zone can be divided into two main groups, one including those that live on the continental shelf and another in the deep-water realm (between the shelf break and the Abyssal zone). On the continental shelf (0 to 100 m depth), frequently in rocky cavities and calcareous concretions, species are commonly of small size with simple lophophore (trocholophe or schizolophe) adaquate in these zones with abundant organic detritus. To this group belong all Argyrotheca species (except A. grandicostata, restricted to deeper waters around the Canary Islands), the tiny Gwynia capsula and L. mediterranea. On the continental slope, extending between the shelf-break (at about 100 m) to about 2000 m in depth (Upper and Middle Bathyal), brachiopods are varied in size with more complex lophophore (generally plectolophe), are abundant, (e.g. Neocrania anomala, Terebratulina retusa, Megerlia truncata, Gryphus vitreus, Megathyris detruncata, Platidia anomioides and P. davidsoni), with two species occurring exclusively in the Atlantic, Macandrevia cranium and Pajaudina atlantica. Some of these species extend also onto the continental shelf.

In deep waters, in the Lower Bathyal to Abyssal zones, shells are commonly thin, delicate, almost transparent, and usually have a complex lophophore (plectolophe or spirolophe), regarded as being more efficient for filtering low concentrations of food particles. Species typical of deep water are Pelagodiscus atlanticus, C. gnomon and H. cornea. The latter species is frequently associated with F. dalliniformis, Dallina septigera, D. parva, Stenosarina sphenoidea, Dyscolia subquadrata, D. wyvillei, Acrobelesia cooperi, Eucalathis tuberata, E. ergastica, Phaneropora incerta, Glaciarcula spitzbergensis, Megerlia monstruosa and Macandrevia novangliae, with the only Argyrotheca, A. grandicostata,- confined to deep waters.

The dorsal valve of C. gnomon, F. dalliniformis, Dallina septigera and Macandrevia novangliae shows a tendency to develop a sulcus. Such species commonly live in deeper waters than those with a sulcus in the ventral valve such as Argyrotheca cordata, A. cistellula, and T. retusa. By contrast, in the southern hemisphere, sulcate brachiopod genera such as Waltonia, Terebratella, Magasella, Magellania, Aerothyris, live in shallow waters.

Fernando ALVAREZ¹ and Tatiana L. MODZALEVSKAYA². ¹Departamento de Geolog’a, Universidad de Oviedo, Oviedo, Spain (fernando@asturias.geol.uniovi.es). ²VSEGEI, Srednij pr. 74, St. Petersburg 199106, Russia (vsegei@mail.wplus.net)

The Athyridia, is a rather rich and diverse group of spire-bearing brachiopods which appeared in the late Ordovician0, Ashgill, possibly Caradoc. At the beginning of the Silurian (Llandovery-Wenlock) the origination number shows a clear increase towards younger strata. Athyridid diversification and dispersal during the early Silurian coincides with warming of the climate and transgression of the ocean. From Wenlock, the number of originations falls towards the younger strata while extinctions show the opposite course. Geographical limitations due to the general late Silurian marine regression may have had some influence. As a result, the late Silurian was the time of the first crisis when 16 genera became extinct.

A new athyridid fauna originated (40 genera appeared) in the early Devonian when the innovation and radiation rates were the highest. These sudden innovations could explain the rise of endemic genera that took place during this period. Later both origination and extinction fall quickly. Extinctions prevailed over appearances and this caused a rapid decline in the athyridids in the late Devonian. 30 genera disappear coinciding with the extinction episode (Frasnian/Famennian). Environmental factors, such as cooling and anoxia, more than marine regression seems to have played an important role in this F-F crisis. The rate of endemism falls from mid Devonian till late Carboniferous. During the Famennian, a clear process of recovery starts. The origination numbers rise until the second half of the Carboniferous system during which a 3rd crises take place (Serpukhovian episode?) and 19 genera disappear. The late Carboniferous athyridids were the most cosmopolitan. However from that time there was a clear tendency for the rate of cosmopolitan genera to decrease while an almost continuous (except during the late Triassic) rise in endemism took place. During the Permian, specially during late Permian, the origination data shows a small rise, but always below the rate of extinction. At the end of Permian, coinciding with the principal mass extinction episode of the Phanerozoic, there was a considerable rise in the extinction rate, 16 genera disappear close to the Permian-Triassic boundary. In the Triassic, with the appearance of the koninckinoids, the last recovery process took place. Origination and extinction show a clear increase (29 genera appear) but extinctions clearly prevailed over appearances, causing a quick decline of the order in latest Triassic. During this period, the level of innovation was low and specialization high, the number of cosmopolitan genera decreased drastically and endemic genera increase considerable. This considerable rise of endemic genera and decline of those widely distributed coincides with the general decline of the order, a decline that began with the widely distributed genera in the late Permian and during the Triassic. By the end of the Triassic a great increase in the extinction rate took place, most of the genera disappear, and the whole order became extinct by mid Jurassic, or at the end of the Jurassic system if the presence of Ochotathyris ochotica, in Qinghai (NW China) is finally confirmed.

Benito ANDRADE¹, Maria Helena HENRIQUES² and Fernando GARCÍA JORAL³

The Cabo Mondego section is the most complete and, probably, the best characterized section of the Aalenian of the Portuguese mesozoic basin regarding the biostratigraphic control based on the ammonite distribution.

The Aalenian corresponds to a series of marl-limestone sediments of about 80 m in thickness developed in more than 300 hundred beds rich in microscopical fragments of different sizes of carbonaceous organic matter and pyrite.

Pyrite is, in many cases, the partial infilling of the brachiopod shells which, sometimes, appear in sindepositional mechanical concentrations. Those features indicate an environment poor in oxygen but rich in organic matter. The brachiopod fauna is characterised by the general small size of the shells and the low specific diversity of the recognised associations.

The first recorded association corresponds to the lower part of the Comptum Subzone of the Opalinum Zone. It is characterised by the scarcity of brachiopods, represented only by a few specimens of Zeilleria anglica and Z. sharpei. The majority of the brachiopod specimens come from the upper part of this Subzone. Besides the two species of Zeilleria previously mentioned, in these levels a third species of the genus appears, characterised by a bigger size and a different morphology. It has been referred to as Zeilleria n. sp. This second association is recognised up to the top of the Bradfordensis Subzone of the Bradfordensis Zone, and passes through the important discontinuity which means the lack of the Murchisonae Zone in the section.

The next recorded Terebratulid association corresponds to the Gigantea Subzone of the Bradfordensis Zone. In this association Zeilleria anglica and Z. sharpei are still found, in the upper levels together with Lophrothyris withingtoniensis. The largest specimens in the whole section belong to the latter species.

Finally, the Concavum Zone is characterised in this section by the absence of Zeilleria sharpei. Z. anglica and Lophrothyris withingtoniensis are very abundant in the Concavum Subzone, and they are replaced by Conarothyris opima in the upper levels of the Limitatum Subzone.

These associations are comparable to the ones described in neighbouring basins of Spain, France and England, although certain differences in the chronostratigraphic distribution of the species are observed.

Lucia ANGIOLINI. Dipartimento di Scienze della Terra, Via Mangiagalli 34, Milano, Italy. (lucia.angiolini@unimi.it).

The brachiopod fauna of the Middle Permian Khuff Formation of Central Oman comprises species of the genera Derbyia, Neochonetes, Celebetes, Haydenella, Chonetellini? genus undetermined, Dyschrestia, Kozlowskia, Calliprotonia, Juresania, Bilotina, Linoproductus, Grandaurispina, Magniplicatina, Cyclacantharia, Acritosia, Orthotichia, Cleiothyridina, Spiriferellina, Dielasma, and Hemiptychina. These are Palaeo-equatorial genera (44%), cosmopolitan (31%), Gondwanan (12.5%) and Cimmerian (12.5%), so it is a mixed/transitional fauna in the sense of Shi et al. (1995), with a dominance of Palaeo-equatorial genera suggesting warm temperate climate conditions.

The mixed character of the fauna provides a firm basis for Peri-Gondwanan correlations, despite the fact that species diversity and rates of faunal turnovers seem to be partly controlled by the vertical succession of depositional environments reflecting an infra-Khuff asymmetric transgressive-regressive cycle. If facies have a clear influence on quantitative distributions of the brachiopod assemblages as well as on species diversity, at least ten taxa show a good biochronological potential value for long distance correlations, their appearance/disappearance being independent from lithological changes.

The Middle Permian brachiopod fauna of North Oman and Emirates, collected partly in the autochthonous Qamar Formation and partly in the Hawasina Nappes, is represented by species of the genera Perigeyerella, Celebetes, Chonetella, Haydenella, Retimarginifera, Transennatia, Stereochia, Karawankina, Bilotina, Juresania, Magniplicatina, Acritosia, Cyclacantharia, Leptodus, Orthotichia, Enteletes, Hustedia, Cleiothyridina, Martinia, Martiniopsis, Cartorhium, Tintoriella, Permophrycodothyris, and Spiriferellina. The occurrence of predominant Palaeo-equatorial genera, associated to cosmopolitan, Cimmerian, and, much more rarely, Gondwanan taxa enhances the transitional characters of this fauna. The two Oman faunas show significant differences in composition, which may have been enhanced by the occurrence of cold upwelling currents along the northern coast (North Oman and Emirates), facing the already opened Neotethyan Ocean.

Due to their mixed character, the Oman brachiopod faunas are ideal for palaeobiogeographical analyses carried out by statistical multivariate methods. Both the Central and North Oman brachiopod faunas have thus been compared to revised coeval faunas of the Peri-Gondwanan fringe, such as the Central Afghanistan (Termier et al., 1974), the Karakorum (Angiolini 1995, 1996), the Salt Range (Waagen 1882-1885; Grant, 1976; Grant, 1993) and in Thailand (Grant, 1976; Archbold 1999), by Cluster Analysis and Principal Coordinate Analysis.

The inferred palaeogeographic scenario shows the northern blocks - represented by the Karakorum and Central Afghanistan - clearly separated by the Neotethys Ocean from the southern ones — represented by Central and North Oman, Salt Range and Thailand - along the Peri-Gondwanan margin. The latter, however, display a clear trend of variation probably related to their palaeolatitudinal position and to the pattern of the palaeocurrents.

AUSTRALIAN PERMIAN PRODUCTIDA: PALAEOBIOGEOGRAPHICAL AND MARINE PALAEOTEMPERATURE IMPLICATIONS.

N.W. ARCHBOLD. School of Ecology and Environment, Deakin University, Rusden Campus, Clayton, Victoria 3168, Australia

Representatives of the Productida are a conspicuous component of the Australasian Permian brachiopod faunas. Members of the Strophalosiidina range from a small to large size and are diverse. They include genera that are endemic, or demonstrate a wider Gondwanan or rarely, possible bipolar distribution. Strophalosiidine genera are rarely shared between the Westralian and the Austrazean faunal provinces. Productidines range from a small to gigantic size, are moderately diverse and also include endemic, wider Gondwanan and possible bipolar elements. Relatively few productidine genera are shared between the two Australasian Permian Provinces. Water temperature is considered to be the principal limiting factor for the migration of Permian genera of the Productida. Westralian faunas exchanged genera with the warmer water faunas of the southern Tethyan margin while Austrazean faunas developed in conditions of variable isolation and cool waters.

Productellids, of small to medium size, include Comuquia, Wooramella, Lethamia and Dyschrestia from the Westralian Province. Lethamia is shared with the Austrazean Province. Dyschrestia has links to peripheral Gondwanan (Cimmerian) blocks, as does Comuquia. Wooramella may be ancestral to Stictozoster. Retimarginifera is known from the Kungurian and Ufimian of Western Australia. Anemonaria, a North American and Arctic genus, is apparently present in the Late Artinskian faunas of Queensland. The only echinoconchoid present in the Australasian Permian is Waagenoconcha (Wimanoconcha), a gigantic subgenus. It occurs in the Westralian Djhulfian (Wuchiapingian).

Dictyoclostids are only present in the Westralian Province and are represented by the genera Callytharrella and Costiferina. The latter genus is also well known from the Late Permian of peripheral Gondwanan regions.

Linoproductids are abundant in the Australasian Permian. Westralian genera include Cimmeriella, Costatumulus, Coolkilella, Magniplicatina, Lyonia and 'Linoproductus'. Lyonia, Costatumulus and Magniplicatina are shared with Austrazean faunas which also include Bandoproductus, Terrakea and Filiconcha as well as the anidanthinids Protoanidanthus, Anidanthus and Megousia.

The Aulostegoidea, regarded herein as being productidines, are well represented by large and gigantic genera in the Australasian Permian. Westralian genera include Aulosteges, Taeniothaerus, a possible Reedoconcha and Megasteges. Austrazean faunas lack Aulosteges but include the three other Westralian genera and Lipanteris.

A particular feature of the productidine faunas of the Australasian Permian is the diverse and abundant development of small to large strophalosiidines. Strophalosiids include the Westralian development of the genera Strophalosia s.l. (probably as Coronalosia), Echinalosia (two species), Notolosia, Etherilosia, the bipolar genus Arcticalosia, Lialosia and the Djhulfian genus Liveringia. Austrazean faunas include over nineteen species of Echinalosia as well as representatives of Strophalosia, Acanthalosia, Pseudostrophalosia and Wyndhamia. The Himalayan genus Marginalosia also occurs in the Lopingian of New Zealand. The anomalous Artinskian endemic? Westralian genus Mingenewia does not fit readily within the Strophalosiioidea and the lone Australasian lyttonioid is the Djhulfian Leptodus from northwestern Australia.

Andrzej BALINSKI. Instytut Paleobiologii PAN, ul. Twarda 51/55, 00-818 Warszawa, Poland.

The study of exceptionally well preserved embryonic shells in the Devonian lingulide brachiopods reveals many details of their morphology and allows for a comparison with other known fossil and extant protegula. The protegula of the Late Devonian Lingulipora and ‘Lingula’ from Poland (Balinski 1997) are very similar to each other in their general morphology. They are subcircular to widely suboval in outline with a blunt end forming the posterior margin. A typical protegulum is convex, cup-shaped, frequently with a flattened or slightly concave central part, and a well-marked thickened peripheral rim. The width of the protegulum ranges from 81 to 100µm and its height reaches up to 25µm. Several well preserved protegula display a distinct and thick radial ribbing or folding. Few other uniquely preserved specimens reveal that these radial folds are associated with radially distributed stresses and nickpoints which resulted in a rheomorphic wrinkling of the protegulum surface. The radial folds may reflect internal grooves that accommodated the embryonic setae. Analogous grooves and setae were found in the protegulum of the recent Discinisca striata (Williams & Holmer 1992). The radially spread nickpoints suggest a radial arrangement of muscles that served as the setal follicels. The studied protegula reveal also that their entire surface is covered by closely packed pits.

Additional exceptionally well-preserved lingulide protegula have been recovered recently from the Early Devonian of Podolia (Ukraine). The additional material includes several small specimens with conjoined valves ranging from 200 to 400µm in width. These specimens died during the larval stage of their growth (i.e., they represent fossil larvae) and this may explain a complete lack of mechanical wearing on the surface of the protegula. The Early Devonain protegula from Podolia and the above described Late Devonian protegula from Poland are strikingly similar in their outline, radial folding, and the pitted surface. The Early Devonian protegula are, however, somewhat smaller attaining 74 to 90µm in width.

The Early and the Late Devonian lingulide protegula show some fundamental differences when compared to the embryonic shells of their extant relatives. The Late Devonian protegula are three times smaller, and the Early Devonian protegula three and half times smaller than the protegula of extant lingulide genera. The radial folding of the surface of the fossil protegula indicates that setae developed during the embryonic growth stage of the Devonian lingulides, whereas in all present-day lingulides the first setae appear as late as the end of their larval stage.

BRACHIOPOD BIOSTRATIGRAPHY OF MIDDLE TRIASSIC IN WESTERN BULGARIA AND COMPARISON WITH BRACHIOPOD ASSEMBLAGES FROM EUROPE

S. BENATOV. Mladost-2, bl. 206, en. 2, ap. 30, Sofia 1799, Bulgaria Fax: +359 2 973-36-03.

Zonal association: Costirhynchopsis vidlicis (most abundant), Angustothyris angustaeformis, Schwagerispira schwageri, Hirsutella aff. hirsuta, Mentzelia cf. ampla, Lima costata, Ånantiostreon spondiloides, Placunopsis ernesti, Megalodon rimosus, Schafhaeutlia schmidi, Chlamis schroeteri. It is found in a small area in the southwest part of Stara Planina Mountain. Similar association including species with different stratigraphic range is found in Fassanian from Lesser Carpathians and Slovak Karst and Bergamasc Alps (Italy).

Juan L. BENEDETTO. CONICET, Facultad de Ciencias Exactas, Fisicas y Naturales, Universidad Nacional de Córdoba, Av. Vélez Sarsfield 299, 5000 Córdoba, Argentina

During the late Tremadoc-early Llanvirn time interval, rhynchonelliformean brachiopod assemblages were almost entirely dominated by orthidines (42%), syntrophidines (23%), plectambonitoids (22%) and clitambonitidines (12%). A survey of about 150 genera from 24 localities throughout the world, including new data from Argentina, shows that inferred palaeolatitude and composition of assemblages at ordinal/subordinal level, expressed as percentage of genera of each order in the total fauna, are significantly correlated, specially in orthidines and syntrophidines. In the Orthidina, even though the taxonomic diversity (number of genera) is almost similar at different latitudes, the percentage of genera increases gradually from low to high latitudes, reaching a peak of dominance in cool to cold N-NW Gondwanan waters (NW Africa, NW Argentina-Bolivia, Armorica, Perunica). The syntrophidine brachiopods, conversely, are highly diversified in low latitudes and, in lesser degree, in intermediate latitudes, but in the subpolar regions are represented only by rare camerelloideans. Plectambonitoids are well diversified in low-latitude carbonates decreasing in number toward the high-latitude siliciclastic basins. Representatives of the Suborder Clitambonitidina attain a maximum at intermediate latitude, in mixed carbonate-clastic and volcaniclastic rocks. These non-random, latitudinally-related, global distribution patterns of ordinal/subordinal diversities and percentages are strongly controlled by water temperature which, in turn, influence the nature of substrate (carbonate vs. siliciclastic sedimentation), water chemistry, nutrients availability, and environmental energy levels, as well as biotic factors such as diversity, feeding strategy and community structure. The question is why did certain groups, such as the Syntrophidines, become dominant in the palaeoequatorial continents but rarely succeed in migrating to high latitudes, while the orthides, for instances, were capable of inhabiting polar to equatorial waters? Thje origin and early radiation of both, pentamerids and orthids, took place in the early-middle Cambrian shallow-water carbonates of the tropical belt. The subsequent Ordovician radiation and migration was mainly controlled by the morphofunctional structure of each group: The strongly biconvex, uniplicate shell of many porambonitaceans was successful in inhabiting shallow-water, low-energy biotopes within carbonate platforms. Their close association with low-latitude sedimentary basins is also evident during the late Ordovician and Silurian. The early orthidines, with a ‘standard’, non-specialised morphology, were less constrained by palaeoenvironmental and palaeoclimatic controls. Plectambonitoideans inhabited preferentially low-energy, deeper waters. A corollary of this study is that the relative abundance of higher brachiopod taxa, expressed as the orthidines/syntrophidines +plectambonitoids ratio may serve as a tool in locating palaeolatitudinally unconstrained terranes bearing early Ordovician brachiopod faunas. The present paper provides a test of the proposed ‘higher taxa ratio’ using recently discovered brachiopod faunas from arc-related, volcaniclastic successions of northwestern Argentina.

Maria Aleksandra BITNER. Institute of Paleobiology, Polish Academy of Sciences, ul. Twarda 51/55,

Population structures of the fossil micromorphic brachiopods from the various shallow water Miocene deposits (from calcareous clays to hard bottom of reef cavities) of the Roztocze Hills, south-eastern Poland have been studied by means of the size-frequency distributions. The following four species were used for the study: Megathiris detruncata (Gmelin), Argyrotheca cuneata (Risso), A. cordata (Risso), and Megerlia truncata (Linneaus), all of which are extant. Twenty eight populations of those species ranging from 78 to 1186 individuals (size classes from 0.5 to 10 mm) were analysed but only those having more than 100 specimens give the meaningful histograms. The rich material obtained from the bulk samples display excellent preservation, high articulation ratio, and low frequency of breakage allowing to consider the investigated populations as unmodified by transportion and/or by mechanical and biological destruction.

The size-frequency distributions for the populations studied here show a wide range of population structures, even within a single species. The distributions can be from right-skewed, through bell-shaped to polymodal ones. No left-skewed distribution was noted. Most of the histograms, however, are right-skewed or moderately right-skewed, where smaller specimens clearly dominate. High frequency of smaller individuals indicates high juvenile mortality which is characteristic for Recent populations of most marine invertebrates. Size-frequency distributions with a large peak in the smaller size classes represent mostly populations collected from marly deposits. Those populations may be interpreted as inhabiting soft bottom where small brachiopods are more threatened with burial by the sediment and/or clogging the lophophore apparatus. The populations collected from the reef cavities produced bell-shaped distribution or distribution with relatively high percent of larger individuals. This may be explained by the fact that the protected hard bottom cryptic reef habitats are characterized by lower juvenile mortality and enable the brachiopods to reach larger size. The obtained results clearly support the opinion of the crucial role of the environmental factors in shaping the population structure of micromorphic brachiopods.

A.J. BOUCOT & Robert B. BLODGETT,. Department of Zoology, Oregon State University, Corvallis, OR 97331, USA.

Silurian-Devonian marine biogeography is dominated through the Eifelian by a global subdivision into a widespread cool to cold climate realm that contrasts with warm conditions elsewhere. Following the Eifelian the global climatic gradient decreased markedly, resulting in the elimination of the cool to cold realm. Laurentian marine faunas display a marked level of endemism through the Givetian, following which there is an overall cosmopolitanism.

Denise BRICE and Jean-Pierre NICOLLIN. Laboratoire de Paléontologie Stratigraphique, Faculté Libre des Sciences et Institut Supérieur d’Agriculture, 13 rue de Toul, 59046 Lille Cedex, France.

During Late Devonian and Early Carboniferous, Spiriferids are common in many platform areas of the eastern part of North Gondwana (North Africa, Central Asia etc.). Some of them seem to be very useful for stratigraphical correlations.

Our aim is 1) to carry out a detailed systematic study of Famennian and Early Carboniferous Spiriferids from preSaharan Morocco and Algeria-Morocco frontier, 2) using to establish a biozonation based on Spiriferids already known elsewhere for these periods a selection of the genera and/or species, 3) to establish a correlation of our brachiopods zonation with the standard conodonts zones and the ammonoids zones.

This paper presents the first results of our investigations. It concerns six index species belonging to five genera which occur in brachiopod faunas chiefly collected by Hollard and Jacquemont near the Morocco-Algeria frontier. The stratigraphical levels of these faunas, given in this paper, have been established by Hollard and published after his death (Hollard, 1981).

The first chosen index species is Cyrtospirifer nov. sp., very common in the upper part of Lower Famennian (II) and the lower part of Upper Famennian (III). This species is compared with other close Cyrtospirifer species and also with another taxon (Enchondrospirifer ghorensis Brice, 1971) which has great external similarities with a new Cyrtospirifer species. The second species is Dmitria seminoi (de Verneuil, 1850) which characterizes the same stratigraphic interval as C. nov. sp. in the area mentioned above and also in some regions of Central Asia. We compare D. seminoi with other Dmitria species and with very close Tenisia species. The fourth and fifth species belong to the genus Eobrachythyris Brice 1971: E. nov. sp. 1 from the Upper Famennian (IV-V) and E. nov. sp. 2 present in Early Carboniferous (Lower Tournaisian). These two species have been accurately described, analysed and compared with other Eobrachythyris species in a former paper (Brice & Nicollin, in press). The sixth species is Prospira struniana (Gosselet 1879) occurring in some Upper Famennian (IV-V) algero-moroccan faunas. The moroccan specimens are compared with the type species from France (Avesnois) (Brice, 1997) and also with Afghan specimens.

Nancy BUENING, University of California, Davis, CA 95616, USA.

Articulate brachiopods synthesize shells composed of both structural macromolecules (lipids, proteins, and polysaccharides) and low-magnesium calcite crystals (with intracrystalline proteins). The shell is the result of an evolutionary design for a hard, impact-resistant material to protect the soft tissues of the brachiopod. The composition and architecture of the primary and secondary layers of the articulate shell have been thoroughly documented at the level of scanning electron microscopy (SEM). I have used transmission electron microscopy (TEM), which allows investigation of structural features on a scale smaller than SEM, to further investigate the ultrastructure of the fibrous calcitic fabric of the secondary layer in both modern and Plio-Pleistocene brachiopod shells of Calloria inconspicua (punctate shell) and Notosaria nigricans (impunctate shells), and in a Late Triassic Kutchithyris sp. (punctate shell) from New Zealand. I have identified an interesting ``tweed'' texture that appears to be pervasive in both the modern and fossil, punctate and impunctate shells. This texture, known as modulated microstructure, has been documented in dolomites, ankerite, and magnesian calcite. To my knowledge, the modulated microstructure in brachiopod shells is the first record of these textures in carbonates composing shells. While the cause of the modulated microstructure is not certain, the proposed explanations suggest either that an excess of magnesium cations disrupts the calcium and magnesium layers in the crystal lattice, or the CO3 groups in the lattice are disordered. It is thought that the distortion of the lattice results in the ``tweed structure''. Magnesium and calcium concentrations measured by electron microprobe analysis confirmed that the brachiopod shells are composed of low-magnesium calcite ( 0.14 to 1.5 mole percent MgCO3). The low levels of magnesium suggest that factors other than excess magnesium are the cause of modulated microstructures in brachiopod shells. It is also possible that a disordered arrangement of CO3 groups has distorted the crystal lattice. However, a published study of dolomite heating suggests that disordered carbonate is produced by temperatures above 1100°C and is metastable, whereas brachiopod shells are formed at surface temperatures and are considered thermodynamically stable. A recent investigation of sea urchin spines, suggests that the adsorption of macromolecules during crystal growth may cause distortion of the crystal lattice. The lattice distortion may strengthen the crystal by interrupting the propagation of cracks along a now-imperfect lattice boundary. The intracrystalline proteins found in brachiopod shells may provide strength to the shell in a similar manner. The modulated microstructures in brachiopod shells may be an expression of lattice distortion, which results from proteins trapped within the secondary layer calcitic fibres.

Monica J. CAMPI & G. R. SHI. School of Ecology and Environment, Deakin University; 662 Blackburn Road Clayton, 3168, Victoria, Australia.

The first record of the genus Permochonetes, and a new species, is described from the Early Permian (Artinskian) Liangshan Formation of the South China block. The new species is placed within Permochonetes Afanasjeva on the basis of close similarity of dorsal internal morphology and presence of external fine capillation; and is separated from the type species, Permochonetes pamiricus Afanasjeva, by the presence of a distinct posteromedian sinus on the ventral umbo, delayed capillation and a much smaller size.

The discovery of the new species has extended the known palaeogeographic range of this genus to include South China, in addition to earlier records from the SE Pamirs and Karakorum Ranges. The presence of this genus in both the Palaeoequatorial Realm and the peri-Gondwanan region indicates the presence of a faunal link between the former and the incipient transitional Cimmerian Region.

The local environment during the deposition of the Liangshan Formation appears to have been a restricted tidal flat or lagoon which experienced frequent sea-level fluctuations associated with the onset of the Yanghsingian transgression. The new species appears to have several morphological adaptations enabling successful exploitation of this environment. It was typically a very small and thin-valved species with a high surface area to volume ratio, an advantage in an oxygen restricted environment. The small size and numerous body spinules would have aided the individuals to remain suspended at the top of the fine, soft substrate. It also dominated the brachiopod assemblage in the Liangshan Formation, comprising up to 94 % of specimens within a bed. These factors indicate that the new species appears to have some of the characteristics of an opportunistic species.

PALAEOECOLOGICAL INTERPRETATION OF THE BARDAHESSIAGH FORMATION (MIDDLE CARADOC), POMEROY, CO. TYRONE, N. IRELAND.

Yves CANDELA. Department of Geology, National University of Ireland, Galway, Ireland.

The Bardahessiagh Formation at Pomeroy, Co. Tyrone, N. Ireland contains a rich, exceptionally preserved fauna of invertebrates, including a significant collection of brachiopods. Jeram et al. (in prep) revised the stratigraphy of the Bardahessiagh Formation, which now comprises three members (in ascending stratigraphical order): the Quarry Sandstone, the Well Field Mudstone and the Mitchell Siltstone Members. The Plectambonitoidea comprise 40% of the brachiopods in the Quarry Sandstone Member to more than 80% in the Well Field Mudstone Member. The analysis of the brachiopod assemblages described from each of these members and their comparison with coeval assemblages from north Wales (Lockley, 1980) and North America (Patzkowsky, 1995), indicates they are all deep water faunas, inhabiting environments below storm-wave base, with typical benthic assemblages equal or greater to 4-5. The examination of the stratigraphical sequence reveals a transgressive event followed by a regressive event during the deposition of the Bardahessiagh Formation, in which the deeper Well Field Mudstone Member assemblage, with its typical low diversity Sericoidea association, represents the acme/peak of the deepening environment. Common elements (at the genus and/or species levels) between the Quarry Sandstone and the Well Field Mudstone members, on the one hand, and, between the Well Field Mudstone and the Mitchell Siltstone members, on the other hand, indicates that changes in environments may not have been abrupt but progressive.

Sandra J. CARLSON¹ and Lindsey R. LEIGHTON² . ¹Department of Geology, University of California, Davis, CA 95616, USA. ²Department of Geological Sciences, Indiana University, Bloomington, IN 47405, USA

Phylogenetic relationships among all the major groups of rhynchonelliform taxa have not yet been examined; analyses among certain subclades have yielded intriguing results (e.g., Williams et al. 1996; Popov et al. 2000). Our goal in this study is to investigate in detail the role of stratigraphic range data, as a source of information independent of morphological data, in the phylogenetic analysis of rhynchonelliform higher taxa. We assembled a list of 37 exemplar genera (approximately one per suborder) that represent, to the best of our current knowledge, the stratigraphically earliest (and perhaps the most morphologically primitive) members of each taxon. Younger members are more likely to have acquired additional apomorphies after their divergence from a common ancestor, and thus be less informative about shared ancestry. Four linguliform and craniiform exemplars were used as outgroups. Each taxon was coded for 45 characters of shell morphology following extensive specimen examination, and 1000 heuristic searches, with random addition of taxa, were run using PAUP 4.0 (Swofford 2000). Initial analyses were further investigated using successive weighting, bootstrap, jackknife, and Bremer support techniques. Results were generally consistent with expectations: rhynchonellates and strophomenates are sister taxa, with the chileates and obolellates basal to this clade. Results were not entirely consistent with the stratigraphic ranges of the terminal taxa, however, most likely indicating homoplastic patterns of shared character convergence.

After initial analyses, the full stratigraphic range of each higher taxon represented by the exemplars was coded. Stratocladistic analyses (using MacClade 3.08; Fisher 1994; Maddison and Maddison 2000) were run to evaluate the stratigraphic "debt" of each of the cladograms obtained with morphology alone, and to reevaluate and reorganize these topologies by incorporating stratigraphic range data directly into the analyses. Because traditional cladistic analyses presume monophyly of all terminal taxa, all common ancestors are hypothetical. Yet, some named higher taxa are clearly paraphyletic (e.g., Syntrophiidina); this unnecessarily complicates both cladistic and stratocladistic reconstructions. We further explored the implications of higher-taxon paraphyly using a program (ANOP; Leighton in prep.) that allows named higher taxa to occupy internal cladogram nodes, as ancestral taxa, utilizing their known stratigraphic ranges. The significance of each of these three types of analysis, allowing stratigraphic data successively more influence in reconstructing phylogenetic relationships, will be discussed. We argue that each method can contribute useful insights into phylogenetic reconstruction, and that the results from no single method are preferable to those obtained using all in comparison with one another.

Gabriela A. CISTERNA¹, Neil W. ARCHBOLD² and Tristán SIMANAUSKAS^{3 1} Facultad de Ciencias Naturales e Instituto Miguel Lillo. Miguel Lillo 205. 4000 San Miguel de Tucumán, Argentina. ² School of Ecology and Environment, Deakin University, Rusden Campus, Clayton, Victoria 3168, Australia. ³Departamento Científico de Geología, Museo de La Plata. Paseo del Bosque s/n. 1900 La Plata, Argentina.

Bernard L. COHEN. IBLS, Division of Molecular Genetics, University of Glasgow, Glasgow, G11 6NU, Scotland, U.K.

At the 1995 Congress and thereafter, using 18S rDNA gene sequences, we presented the first genealogical evidence for relationships amongst all extant brachiopod major lineages, together with data suggesting phoronid and brachiopod monophyly, with a possible sister-group relation between phoronids and craniids (Cohen & Gawthrop, 1996, Cohen et al., 1998) Ectoprocts, though poorly sampled, were excluded from the brachiopod+phoronid clade. All these phyla clustered with undoubted protostomes, not with deuterostomes (Field et al., 1988, Halanych et al., 1995). Open questions centred on (i) particular articulates (e.g. Platidia, thecideidines), (ii) whether phoronids are monophyletic, (iii) the positions of unsampled brachiopod taxa. Since 1995, independent genetic evidence from mitochondrial DNA (mtDNA) has supported the protostome relationship and confirmed the 18S rDNA gene tree for selected short-looped taxa (Cohen et al., 1998), has established that phoronids are, indeed, monophyletic(Cohen, 2000), and has confirmed the outgroup position of a representative sample of ectoprocts (Giribet et al., 2000). Thus, the foundations laid earlier have been tested and proved generally secure.

At this Congress we shall report new sequence data that (a) suggest genealogical relationships for previously unsampled taxa and (b) resolve some open questions.

Paul COPPER. Department of Earth Sciences, Laurentian University, Sudbury, Canada P3E 2C6. (pcopper@nickel.laurentian.ca)

Atrypid brachiopods originated during the late Llanvirn (Llandeilo) benthic ‘shelly’ radiation, and the last taxa disappeared towards the Frasnian-Famennian extinction boundary, so that the order endured for close to 100Ma, commonly numerically dominating many other brachiopods in shallow water communities. All species are known to have been exclusively tropical, and preferentially subtidal carbonate shelf and ramp inhabitants: more than 200 genera and subgenera have been described. Using the latest generic diversity compilation at the stage level, including synonymies, the Caradoc (11 genera) and Ashgill (9) mark a slow rise and arrival of the major suborders and families. The ‘Zygospira group’ (Anazygidina), which dominated prior to the Ordovician / Silurian boundary , i.e. Hirnantian, mass extinction events, were taken over by the ‘Atrypa group’ (Atrypidina) in the latest Ordovician. By the late Llandovery (Telychian), 32 genera proliferated, including many smooth-shelled taxa (Lissatrypidina), the largest expansion of the Atrypida during their history, a diversity maintained to the end of the Ludlow-Pridoli. The Early Devonian (Lochkov) saw a decline to 20 genera, with a slow return by the end of the Pragian, a tectonically active phase marked by global sealevel drawdowns, and provinciality. The late Emsian-Eifelian marked a peak in atrypoid diversity, reaching a maximum of 41 genera, coinciding with a global greenhouse setting and reef expansion, with many taxa specifically adapted to and confined to reefal carbonates. Diversity declined in the mid-Givetian, and was reduced by 50% towards the end-Givetian, with dramatic losses of reefal taxa, many at the family level. The Frasnian was a stage of low diversity (12 genera), though there was local high abundance especially in mid-Frasnian time, up to the Palmatolepis rhenana conodont zone: long-lived, cosmopolitan taxa dominated, with some new arrivals within the family Atrypidae. Within the latest Frasnian P. triangularis Zone, most regions saw fewer than two or three genera prevailing: there are no mass ‘death horizons’ known, and declines were stepdown events, probably tied in to sealevel oscillations (T/R cycles), with virtual absence of atrypids in the uppermost meters of strata with a complete F/F succession. There are no Atrypida known from the Famennian, except as reworked Frasnian shells, thus a long-lived and highly successful group came to an end.

Robert Samuel CRAIG. School of Applied Geology, Curtin University of Technology,

Recent research on the Late Cretaceous and Cenozoic fossil brachiopods of Western Australia has added much to our understanding of their systematics and biodiversity. Fifty-eight species, including one new family, two new general and thirty new species have been described from the deposits.

Four, possibly five, genera and one species from the Late Cretaceous deposits of Western Australia are common to the Late Cretaceous deposits of the Antarctic Peninsula. This evidence has led to the proposal that in the Late Cretaceous there was a common shelf environment from the Antarctic Peninsula to the north-west coast of Western Australia. These southern shelf environments formed the high latitude southern circum-Indo-Atlantic faunal province. In this area, brachiopods evolved different general and species than those in the northern hemisphere. Many then dispersed into northern areas of the Indian, Atlantic and finally, Pacific Oceans.

In the examination of the Cenozoic material from the Carnarvon Basin, it is also clear that there is a strong correlation with Cenozoic material from the Antarctic Peninsula. At least four brachiopod genera are common to the two deposits.

If the distribution of brachiopods in Australia and New Zealand is analysed, they first appear in the north-west of Western Australia. They then appear in chronological order in the south-western, south-eastern basins of Australia and finally New Zealand. The distribution of the brachiopods south then eastward was most likely due to the Proto-Leeuwin and Great Australian Bight Currents. Fifteen species are common to south-western Australia and south-eastern Australia.

Brachiopods may well have used various migration mechanisms from the earliest breaching of the gap between Australia and Antarctica to be transported into the Tasman Sea and hence to New Zealand. This included attachment to drifting wood, seaweed and living fauna as well as possible extended larval life in lower temperature waters.

The small number of species and specimens of brachiopods in some deposits needs explanation. Brachiopods are avoiders of light, tending to attach or lie in shadow or underneath objects in shallow photic zones. Those deposits with fewer brachiopods appear to be within the photic zone.

Another possible explanation is food availability. Lophophorates are able to take advantage of areas where food supplies are limited and hence can out-compete the molluscs that require a larger food supply. Where food sources are plentiful, molluscs out-compete the brachiopods for available substrate and hence the brachiopod numbers, genera and/or specimens are reduced.

Gordon B. CURRY¹, Richard CONNOR² and Fabio SIMEONI². ¹Division of Earth Sciences, University of Glasgow, G12 8QQ, UK. ²Department of Computing Science, University of Strathclyde, Glasgow, UK.

Conventional database management systems have a number of major limitations if the data concerned are not perfectly regular. Data generally must be transformed or recoded to fit the data fields, and this is extremely time-consuming and prone to introducing errors. Often considerable proportions of the original data cannot be entered into the database (due to limitations on the number of characters allowed in each data field), and certain types of information cannot readily be compartmentalised and are often lost. Further problems arise because the underlying data model is designed to deal with fully completed data fields, and most databases contain at least some, if not many, empty fields. Database schemas are complex and difficult to design, and this can result in disproportionate amounts of time being devoted to creating a database rather than to analysing the information it contains. It is also highly desirable to update databases regularly, but this again is not straightforward.

If the original data is instead left as text files, then in computing terms the fundamental problem is that it lacks ‘structure’, and is seen by the computer simply as a string of characters. As a result, only very simple queries are possible (e.g. find the text string ‘abc’ or ‘xyx’), and these are totally unsuitable for most applications. Conventional databases impose structure by putting the information into named compartments (the data fields) which does allow sophisticated queries to be run over the data, but at the cost of all the problems mentioned above.

This project has taken an entirely different approach to the storage and querying of biodiversity information. The method exploits the fact that some types of text do display a certain amount of inherent ‘structure’. Taxonomic descriptions are good examples of such ‘loosely-structured’ or ‘semi-structured’ data, as the order, nature, and content of formal descriptions are constrained by well-established conventions. Our new protocol automatically detects this structure in taxonomic descriptions and creates named ‘tags’ around appropriate segments of text. The result is a single document containing internal markers of the type needed to perform sophisticated queries.

A new procedure will be demonstrated using data which are being analysed for the chapter on ‘Stratigraphic Distribution’ in the new Brachiopod Treatise. The main advantages of the new procedure compared to a database approach are that it: a) is very quick to set up, b) retains all the original text, c) allows unlimited amounts of information in each ‘field’, d) can readily be updated with extra or changed information, and e) allows sophisticated queries. Applying this technique to the brachiopod genera has also automatically generated a lexicon of terminology which is of potentially wider application in allowing the extraction of information from less-structured text (e.g. scientific papers). The capabilities and potential of this new approach will be demonstrated with examples from the stratigraphic distribution of brachiopods.

Maggie CUSACK¹ and Alwyn WILLIAMS². ¹Division of Earth Sciences and ²Palaeobiology Unit, University of Glasgow, Glasgow, G12 8QQ, U.K.

The structure of the rhynchonellate brachiopod shell, as typified by living rhynchonellides, consists of a primary layer of growth-banded calcite secreted on an organic periostracum and succeeded by a secondary layer of fibres sheathed in interconnected glycoproteinaceous membranes. The extreme variations of this standard succession include the atrophy of the secondary layer in living thecideidine shells which virtually consist of primary layer and the development of a tertiary layer of ‘prismatic’ calcite in some terebratulide shells. As the standard succession characterized the shells of early Cambrian species, it is assumed to be ancestral to the thecideidine and terebratulide variants.

The biochemistry of rhynchonellate shells has hitherto been determined for entire valves and has confirmed the presence of many intracrystalline proteins including some that are involved in calcification during shell growth. The assumptions that Thecidellina shells are almost pure primary layer and (terebratulide) Liothyrella shells would alone contain calcifying proteins involved the secretion of the tertiary layer, prompted a chemico-structural comparison of such shells with those of the rhynchonellide Notosaria.

The shell structure of all species is virtually identical in correlated layers. The basic calcitic unit is a granule, c. 15 nm in diameter, aggregated as rhombohedral tablets and spherules that are probably ‘glued’ together by a polysaccharide to form laminae. In the primary and tertiary layers, laminae are nearly horizontal even within outgrowths like thecideidine tubercles. In fibrous secondary layers, laminae are variably inclined but normally retain the same crystallographic alignment not only among contiguous fibres but also with those of the primary and tertiary layers. Laminae of fibres which are contained within coats of granules nucleated on sheathing membranes, commonly aggregate as rhombohedral laths. Such laths cleave parallel with rhombohedral angles subtended by the proximal boundaries of terminal faces.

Fifteen or so proteins, with molecular weights varying from 16 to 126 kDa, have been extracted from intracrystalline residues of the shells studied. No soluble proteins, however, could be identified as specific to, and therefore involved exclusively in the calcification of, one or other of the principal layers of the shell. Some proteins are probably the actin-like strands that sporadically ramify laminae; others, occupying grooves and pits in secondary layers, could be inclusions of intercrystalline substrates. It is also likely that many represent molecular transformations that occurred after the divergence of the thecideidines and the terebratulides from their sister rhynchonellides.

Mohammad DASTANPOUR, Department of Geology, Shahid Bahonar University, Kerman, Iran.

In northern areas of Kerman Province, south-east central Iran, Frasnian successions contain the richest known Devonian brachiopod faunas in the country. Lithologies are mostly bedded limestones, with interbedded sandstones and shales, and the carbonates contain diverse level bottom communities in which 15 genera of brachiopods are present. In sections at Harus and Gerik, 75 km north of Kerman City on the eastern and western flanks of the Hojedk syncline, respectively, there are small coral build-ups which contain a distinctive brachiopod community dominated by Spinatrypina.

Thamnopora and Disphyllum are the most common of 10 coral genera. The distribution of Spinatrypina is restricted to within and the very close vicinity of the coral build-ups. Specimens increase in size, abundance and density of packing inwards toward the coral growths, where other brachiopod taxa are rare or absent. At slightly higher levels in the sequence, Spinatrypina and other atrypide taxa disappear across an interval that is taken to span the Frasnian — Famennian boundary.

Stephen K. DONOVAN¹ & David A.T. HARPER²

Surviving members of the Palaeozoic fauna, particularly brachiopods and crinoids, flourish in the deeper waters of the Caribbean as sessile, suspension-feeding epifauna. Crinoids commonly occur with brachiopods in Antillean, late Cenozoic deposits, although the reverse is not always true. The fossil records of these groups, dependent upon the uplift of deeper water sedimentary rocks, has been inadequately studied within the region.

In contrast to Oligocene biotas, Miocene brachiopod faunas are relatively diverse. Six species of Argyrotheca, together with Lacazella, Platidia, Terebratulina, Thecidella and Tichosina, occur in the Mantazas Province of Cuba, whereas Cryptopora, Gryphus and Tichosina occur in the Habana Province. Mid-Tertiary reefal facies have yielded Argyrotheca and Lacazella together with rare terebratulids in Puerto Rico. New reports of Terebratulina and Tichosina in Jamaica have expanded the distribution of the Miocene fauna in the Caribbean. Additionally, relatively diverse brachiopod assemblages from the Miocene of Carriacou contain terebratulide genera not known elsewhere in the region. The Miocene rocks of the Bissex Hill section on Barbados are characterized by a number of micromorphic taxa, including Argyrotheca. Most faunas probably occupied relatively deep-water facies and some favoured cryptic niches. Nevertheless, the Miocene brachiopod fauna varies across the Caribbean, presumably controlled by local environmental factors together with depth of water.

Crinoid ossicles are now known in association with brachiopods from the Miocene of Barbados and Carriacou. The only coeval, Antillean crinoid hitherto described was Diplocrinus from the Miocene chalks of Jamaica. Hundreds of ossicles have been collected from the Miocene of Barbados and Carriacou, including the isocrinids Neocrinus and Diplocrinus, the bourgueticrinid Democrinus and rare comatulid centrodorsals. Faunas are dominated by the columnals of isocrinids; bourgueticrinid columnals and comatulid centrodorsals are very rare. This is despite the comatulids being the most diverse crinoids in the modern Antillean fauna and the only group that occurs in shallow-water environments. Post-Eocene crinoid faunas are similar, at least at the generic level, to those of the present day; a similar pattern is recognised in the echinoids.

The complete absence of brachiopods in the Pliocene Bowden shell bed of Jamaica, which includes a wide range of biofacies, gives support to the observation that the phylum was not a common component of the Caribbean biota at that time. Low diversity associations continue through the Pleistocene, contrasting with the relatively diverse extant faunas of the Caribbean Sea. This low diversity profile contrasts with the high brachiopod diversities in the late Cenozoic of the Mediterranean basin, implying that regional rather than global factors were more important controls on local diversity.

Research supported by National Geographic Society grants #5722-96 and #6625-99.

Alfred DULAI. Hungarian Natural History Museum, Department of Geology and Paleontology, Budapest, P. O. Box 137, Hungary, H-1431. (dulai@paleo.nhmus.hu).

The earliest Jurassic brachiopods were only known previously in Hungary from the Transdanubian Central Range Recently bed-by-bed collections were made at 17 localities in the Bakony and Gerecse Mountains. The new collections yielded surprisingly rich faunas: 14 species from the Hettangian and 64 species from the Lower Sinemurian. Twelve species are described for the first time from Hungary and the stratigraphic ranges of another 44 species are now known from the study area. The global stratigraphic ranges of 14 species are modified: these species appeared earlier in the Transdanubian Central Range than in other areas.After the end-Triassic mass extinctions, the diversity of the brachiopod fauna did not increase as evenly and gradually from the Hettangian to the Pliensbachian as was previously thought; in fact a rapid and sudden diversification occurred in the Hettangian and Early Sinemurian. Nine genera were already present in the Hettangian and 22 genera were represented in the Bucklandi Zone. The maximum diversity of the Early Jurassic brachiopod fauna was reached by the Sinemurian. The taxonomic composition of the Hettangian faunas of the Transdanubian Central Range clearly show that the niche replacement previously ascribed to the Triassic/Jurassic happened only after the Hettangian. The comparison of the deep water groups suggest that Early Jurassic basins were deeper in the Bakony than in the Gerecse Mountains.

Eva EGERQUIST. Institute of Earth Sciences Department of Historical Geology and Palaeontology, University of Uppsala, Norbyvägen 22, S-75236, Uppsala, Sweden. (Eva.Egerquist@pal.uu.se).

The early Ordovician carbonates of the St. Petersburg District, Russia, appear to include

storm-generated deposits (tempestites) containing allochthonous faunas, which may have been transported a considerable distance. The numerous intercalating, very fine and highly argillaceous silt layers probably represent the background deposition, containing an autochthonous fauna. These well-defined soft layers are excellent for studying faunal variations, both spatial and temporal. The study has concentrated on the clay layers from Putilovo Quarry, east of St. Petersburg, in particular the succession of brachiopod assemblages from the middle and upper Volkhov regional stage (Paroistodus originalis - Microzarkodina parva Conodont biozones). The brachiopod assemblages have a rather constant composition in most samples, with Paurorthis and Ranorthis as dominating genera. Other genera that are less abundant, but occur throughout the investigated section, are Nothorthis, Productorthis, Antigonambonites and Ingria, whereas Apomatella and Ujukella appear higher up in the sequence. Calculation of the relative abundance of the dominant genera reveals an interesting co-variation between Paurorthis and Ranorthis, showing a plausible correlation with the suggested sea-level curve for the region. Materials from a coeval carbonate mud mound, located in the central part of the quarry, show a somewhat different faunal composition as compared with the surrounding clays. In the clay core, articulated specimens of Ranorthis trivia strongly dominate the community. Some brachiopods not represented in the normal clays occur in these thick mud accumulations, including two new orthid species.

Christian C. EMIG. Station Marine d’Endoume, rue de la Batterie-des-Lions, 13007 Marseille, France.

Most of the taxonomic characters of extant lingulide species, as defined by Emig (1982, 1983), can and have to be applied to fossil lingulid forms. This statement is based on the studies of several hundreds of specimens from all the species belonging to the following lingulid genera : Lingula, Glottidia (see Emig 1982), Lingularia (see Biernat & Emig 1993, Marquez-Aliaga et al., 1999), Dignomia (see Gagnier et al. 1996), as well as Obolus, Ungula, Oepikites, and Schmidtites (unpublished data).

In the linguloid taxa, general shell features cannot be used alone to identify or discriminate either genus or species, but soft-bodied (i.e. internal) morphological characters must be used too. Furthermore, to be confident of the variability, all of the taxonomic characters must be measured, compared and discussed within the taxon and between all possible relatives before creating any new linguloid genus or species. Such descriptions have to be based on at least 20-30 well-preserved specimens, avoiding fragments or broken shells. Any description simply based on shell shape and size or using non-phylogenetical features to distinguish the so-called closely related species should have no taxonomic value, as well as too-short diagnoses that do not allow one to do valuable identifications. Such descriptions just increase confusion in identifying and describing lingulid species.

The main taxonomic characters which have to be described and represented are: umbonal region (internal, external, and sometimes profile); internal musculature arrangement and disposition; main anterior mantle canals. The shape and size of the shell can be given but their taxonomic value must be demonstrated, except when the shell shows a very specific feature. Several examples will be given and discussed. Recommendations 13A and 13B of the 4th Edition of the ICZN are emphasized, particularly in the description of higher taxa.

Kazuyoshi ENDO. Department of Earth and Planetary Sciences, University of Tokyo, 7-3-1 Hongo, Tokyo 113-0033, Japan.

Supra-phylum affinities of brachiopods to other animals have been puzzling for more than a century. Recent studies of 18S ribosomal RNA sequences clearly indicate that brachiopods are protostomes and are closely related to those bearing a trochophore larva, such as annelids, sipunculans, and molluscs, collectively forming a clade known as lophotrochozoa, or eutrochozoa. Analyses of other molecular markers, including the elongation factor 1 alpha gene and some mitochondrial (mt) genome features, largely support this view. Resolving relationships among eutrochozoans, however, is still a demanding task, probably reflecting the fact that ancestors of those phyla diverged within relatively a short period of time. Published mt-gene maps of 89 metazoans, including two brachiopods, representing 9 animal phyla, were examined to identify relationship patterns. Since relative positions of tRNA genes can vary even within phyla, only the arrangements of the 13 protein and the two rRNA genes were considered. For each pair of mt-gene maps, the minimum number of consecutive steps, either of translocation or inversion of a block of genes, required to interconvert the maps, were counted and the gene maps were interconnected to one another assuming minimum evolution. Examined in this way, the echinoid map is connected to the common chordate map with two steps, and the arthropod map is united with the chordate map by three steps. The arthropod map is then connected, by two steps, with the mollusc map, with which the annelid map is linked by a minimum of four steps. The brachiopod map is connected with the mollusc map by a single inversion, which turned out to be the required first step in the minimum routes from the mollusc map to the annelid map. Similarly, the mollusc map lies in one of the shortest routes, which involves three steps, from the arthropod map to the brachiopod map. Lack of an appropriate outgroup hinders rooting of the ‘tree’, or network, of these mt-gene maps of bilateral animals, but a conserved gene assortment in a diploblastic coral mt-genome tends to indicate that the root resides between chordates and arthropods. Those observations suggest that the mollusc map is ancestral to the brachiopod and annelid maps, and that brachiopods are more closely related to annelids than to molluscs.

FAN Bing-Heng and HE Xi-Lin. Mineral Resources and Environmental Science College,

The Late Paleozoic strata (Carboniferous to Lower Permian) in studied area mainly composed of detrital deposits, coal and carbonate deposits containing numerous marine fossils, was remarkably developed. It is very important for the further biostratigraphic work to the exploration of coal and other new energy resources. Abundant brachiopod fossils were collected from seven sections and locations respectively situated Shanxi, Hebei, Shandong and Liaoning. Altogether, 66 genera and 230 species are identified, among them 1 genus and 71 species are new. (Some new data have been published in 1995). The new forms, as well as some previously reported ones, are described and remarked in detail. Up to now, this is the most complete and abundant data on brachiopods in North China Platform. The features of brachiopod fauna indicate that Spiriferida and Productida are two most prevalent groups, and Rhynchonellida, Strophomenida, Terebratulida are also flourished during that time, and of a significant biostratigraphic value. However, their taxonomic components, diversities and abundances are quite different in different stages. According to the brachiopod characteristics, eight assemblage zones are recognized in North China Platform in descending order as follows: Lower Permian 8. Lingula. 7. Martinia simiplana - Purdonella Pseudonikitini - Choristites jigulensis. 6. Alexania gratiodentalis - Notothyris nucleolus - Paraspiriferina sinkiangensis. 5. Beecheria minima - Enteletes hemiplicata. 4. Derbyia shanxiensis - Brachythyrina strangwaysi - Chonetinella flemingi. Upper Carboniferous 3. Chonetes sarcinulatus - Chonetinella lata. 2. Brachythyrina lata - Choristites yanghukouensis - Echinoconchus elegans. 1. Linoproductus liaoningensis - Choristites crassicostatus.

The correlation between the brachiopods from research area and those from other parts of the world suggests that the fauna during the late Early Carboniferous, which is only discovered in Taizine region, can be compared with that in Tianshan, Xinjiang. However, the fauna after that time shows close affinity with those in South China, the Western part of China and the Moscow Basin, Ural and Timan sea.

Based on the statistical analysis of brachiopod fauna and sedimentary features, five communities are proposed. They are, respectively: 1. Linoproductus - Ovatia community near the low-tide line of gulf connecting with normal sea. 2. Derbyia community living on an open-basin connecting with normal sea. 3. Beecheria - Stenoscisma community near the wave plane or on the restrained carbonate rock terrace. 4. Lingula - Chonetes community inhabiting lagoonal environment. 5. Undertidal wave zone community (it is very difficult to give a fossil name of community).

The authors also discuss the time and space distribution and the sedimentary features of Tianshifu formation on the basis of modern stratigraphic viewpoint, and thinks that this formation as a lithostratigraphic unit has great significance for the lithological subdivision in North China Platform. Furthermore, the late Early Carboniferous strata in studied area are confirmed and analyzed, which is a noteworthy progress in regional geological research. Ultimately, the authors also deal with the boundary between Carboniferous and the Permian, and hold that the boundary be drawn at the base of Pseudoschwagerina Zone, that is, the appearance of Pseudoschwagerina, Chalaroschwagerina nelsoni, Pseudofusulina or the base of brachiopod Derbyia shanxiensis - Brachythyrina strangwaysi - Chonetinella flemingi Zone. The equivalent boundary is at the base of the Miaogou limestone of the typical section in Xishan (West hill) of Taiyuan, Shanxi Province.

Howard R. FELDMAN¹, Ellis OWEN² and Francis HIRSCH³. ¹Department of Invertebrates, American Museum of Natural History, New York, NY 10024-5192, USA. (feldman@amnh.org). ²Department of Palaeontology, The Natural History Museum, South Kensington, London SW7 5BD, UK. (ellis.owen@talk21.com). ³Geological Survey of Israel, 30 Malkhei Yisrael Street, Jerusalem, Israel. (hirsch@mail.gsi.il).

Field collecting in Hamahktesh Hagadol, an erosional cirque excavated from the axial culmination of the Kurnub Anticline in the northern Negev, has enabled us to compare several endemic brachiopod faunas from within the margins of the Ethiopian Province bordered on the north by the southern limit of the Tethys Sea. From the Callovian Zohar and Matmor formations in southern Israel, consisting of marls, shales and limestones, we have systematically described thirteen species of brachiopods (2 rhynchonellids, 11 terebratulids ) referred to twelve genera: Burmirhynchia jirbaensis, Somalirhynchia africana, Apatecosia inornata , Bihenithyris mediocostata , Ptyctothyris daghaniensis Striithyris saudiarabica , Pleuroloma triangulatum , Zeilleria sp., as well as new species of Striithyris , Kutchithyris, Dissoria , Digonella , and a new genus. The brachiopods described herein comprise a fauna located at the northernmost part of the Indo-African Faunal realm within the Jurassic Ethiopian Province. Brachiopods are often facies controlled, the changes in deposits denoting a difference in temperature, salinity and depth. Rhynchonellids and costate terebratulids are found in deposits of high energy and very often in clusters. Such a fauna dominates the deposits in the northern outcrops, such as those from northern Sinai which display a predominence of Somalirhynchia and Burmirhynchia. Smooth terebratulids are more often to be found in deeper water facies, which is the situation in the southern deposits, as those in the Negev.

Laing FERGUSON. Mount Allison University, Sackville, New Brunswick, Canada.

Gary FREEMAN. Section of Integrative Biology, University of Texas, Austin, Texas 78712, U.S.A.

Paleontological evidence indicates that a large number of new animal phyla, in addition to classes and orders within phyla, were first observed during the Cambrian. One possible basis for the genesis of new morphologies during this period may have been the ease with which the developmental programs responsible for regional specification during early development could be changed. Subsequently these developmental programs are postulated to have become more tightly integrated making changes in early development more difficult to effect and thereby reducing the variation that natural selection can operate on. Within the Linguliformea and Craniiformea, extant lingulids, discinids and craniids belong to orders that originated during the Cambrian. The other Order, Terebratulida, with extant families, originated via a series of intermediate forms, from a pentameride ancestor at the base of the Devonian. It is not possible to go back in time and study the embryology of Cambrian animals. However, by comparing cleavage patterns, fate maps, patterns of morphogenetic movements during gastrulation, the timing of regional specification during early development, and the kinds of mechanisms responsible for regional specification in extant species one can assess whether there is more variation in the ways of going about early development of descendants of orders that originated during the Cambrian versus descendants of the Order Terebratulida which originated later. The various regions of the larvae of extant brachiopods can be homologized with each other. There are major differences in early embryogenesis in Glottidia, Discinisca, Crania, and Hemithyris which belong to groups that originated during the Cambrian. There are essentially no differences in the early embryologies of Hemithyris, and two representatives of the Order Terebratulida: the short looped Terebratulina and the long looped Terebratalia although these forms are morphologically disparate.

Makoto FUKUMOTO, Division of Cell Function, Institute of Natural Sciences, Nagoya City Univ. Mizuho-ku, Japan.

As a preliminaly study on fertilization in the Brachiopoda, I present the acrosome differentiation during spermiogenesis and acrosome reaction in L. anatina.

1. Fully Differentiated Spermatozoa of L. anatina. The spermatozoon of L. anatina is approximately 50 um long. It has a head (about 2 um long), a midpiece (about 1 um long) and a tail with a tapered end. The midpiece is a ring consisted of several mitochondria. The pear-shaped acrosome has an electron-dense structure enclosing the main part of the acrosome just inside the acrosomal outer membrane. This structure has striations. The acrosomal inner membrane shows indentation in the basal part of the acrosome. The subacrosomal substance accumulates in the space between the basal part of the acrosome and the anterior region of the nucleus.

2. Acrosome Differentiation. In a spermatocyte, proacrosomal granules are observed scattered in the cytoplasm. A fairly well developed Golgi apparatus seems to produce proacrosomal granules in the cytoplasm. During spermiogenesis, proacrosomal vesicle appears to become larger with the addition of proacrosomal granules. Subacrosomal substance accumulates outside the region where the electron-dense structure is not present. Proacrosomal vesicle seems to rotate and take in the position opposite to the centriolar fossa.

3. Acrosome Reaction. Acrosome reaction seems to begin by membrane fusion between the plasma membrane and the acrosomal outer membrane at the anterior region of the sperm head. Acrosomal substance is released through the opening of the anterior region of the acrosome. The acrosomal inner membrane is extending out after the release of the acrosomal substance. Acrosomal outer membrane bends and become inside out. The acrosomal inner membrane protrudes out as a acrosomal process in which fine filaments are observed. Fuzzy material decorates the outside of the acrosomal process.

Fernando GARCÍA JORAL¹, Antonio GOY¹ y Miquel DE RENZI^{2 1} Depto. y UEI de Paleontología, Facultad de Ciencias Geológicas (UCM) e Instituto de Geología Económica, (CSIC-UCM). E-28040 Madrid Spain. ² Institut Cavanilles de Biodiversitat i Biologia evolutiva. Universitat de Valencia. Apdo. Correos 22085, E-46071 Valencia, Spain.

The study of several sections of the Lower Toarcian in the Iberian, Basque-Cantabrian and Asturian basins has shown significant changes in the brachiopod associations that can be interpreted in evolutionary, paleoecologic and paleobiogeographic terms.

The taxonomic composition of the four recognised associations show no important differences among these basins, although changes in the relative abundance of the taxa are observed. Thus, a gradient of diversity can be seen, so that the associations are gradually less diverse to the Northwest showing the maximum number of species in the Central Sector of the Iberian Basin and the minimum in the Asturian Basin. Furthermore, this gradient gets more important with time, to the point that the last two associations in the Asturian Basin are absent.

On the other hand, a remarkable decrease in the size of the individuals is observed with the same polarity (maximum size in the Iberian Range and minimal size in Asturias). This is not necessarily because of a miniaturisation of the taxa, since in most cases it is due to a dominance towards the Northwest of the small size taxa.

The causes of these changes might be related with environmental differences; mainly in the nature of the substratum and in the oxygenation of the bottom. The anoxic episode that affects to the Western Tethys along the Tenuicostatum and the lower part of the Serpentinus Zones might have had less influence in the more internal areas of the Iberian Basin, which could have worked as a refuge area for some taxa.

A widespread extinction takes place at the transit between Tenuicostatum and Serpentinus Zones, followed by a brief episode without record of brachiopods. In the Asturian Basin and in most of the Basque-Cantabrian Basin the brachiopods do not recover until the upper Toarcian; whereas in the Iberian Basin a new colonisation and diversification takes place immediately. It begins with highly numerous and polimorphic populations of S. bouchardi, a species that has a wide geographical distribution. The next association includes numerous taxa of the Spanish Bioprovince, such as several species of the genera Homoeorhynchia and Telothyris, and it extends trough the Serpentinus and part of the Bifrons Zones.

The fact that these last two associations are recognised in several regions close to the Iberian Massif (Portugal, Catalonia, Provence, Middle Atlas of Morocco and Algeria) but not in its northern border, might be related with a difference in environmental conditions, since no biogeographic barriers have been recognised. It is possible that the differences that caused the gradient of diversity in the Tenuicostatum Zone persisted in the Serpentinus and Bifrons Zones, accentuated by the generalised rise of the sea level that has been invoked for these biocrones.

Daniele GASPARD. Université de Paris-Sud, Sciences de la Terre, Bât. 509, 91405 Orsay Cedex, France.

Collections of Recent Brachiopods from the Paleobiology Department of the Smithsonian Institution (Washington DC) and those from the Leiden Rijksmuseum and the Paris Museum allow us to revise the brachiopod fauna of the Lesser Antillas already listed by Crosse (1865), Crosse & Fischer (1866), Dall (1920), Cooper (1977), Logan (1990), and Gaspard (1998).

The fauna comprised about twenty species of which 2 Inarticulata species: Discradisca antillarum (d'Orbigny) and Pelagodiscus atlanticus (King) and 7 Articulata genera: Tichosina Cooper, Stenosarina Cooper, Terebratulina d'Orbigny, Clidonophora Dall, Argyrotheca Dall, Platidia Costa and Dallina Beecher.

Tichosina and Argyrotheca are well represented. Tichosina includes: bartletti, cubensis, dubia, floridensis, labiata, martinicensis, obesa, plicata and rotundovata, greatly variable in size and characterized by an additional prismatic shell layer. They are common between 100 and 500m but never reach 1000m in depth. The genus Argyrotheca includes barrettiana, bermudana, crassa, hewatti, rubrocostata and rubrotincta, abundant and small shells mainly found in shallow waters, closely attached to undersides of large empty shells and coral structures. The species are identified better by their internal characters than by the external colour banding, often removed or blurred when dry.

The genus Stenosarina Cooper (1977), here recognized with two species: angustata and nitens, needs more material for observations, while the species of Tichosina are in need of thorough revision.

In the region three genera are monospecifi: Dallina floridana (Pourtalès) is characterized by a triangular shaped shell and a complex loop structure evolving during morphogenesis with stages of resorption. This species is often found with T. cubensis around Anguilla as it is the case in other locations. Clidonophora incerta (Davidson), found near St.

Vincent is the deepest species in the Caribbean. Platidia anomioïdes (Sacchi & Philippi) a small round shaped shell is not as common in the Caribbean (St Vincent, Dominica) as in the Mediterranean Sea and the eastern Atlantic (off Portugal and NW Africa) with a widespread bathymetric range.

The species most widely distributed here and in all the Caribbean is Terebratulina cailleti Crosse represented by a small shell in a widespread bathymetric range. Its shell is multicostellate and juveniles exhibit beaded costellae; the median sulcus on the dorsal valve is pronounced and the short loop presents a ring, the dorsal part of which is oriented ventro-anteriorly with sometimes modifications in the curvature and additional expansions. Considering the last feature, numerous comparisons between specimens of the different locations in the Caribbean are needed, the same objection is required concerning the crural process. In comparison Terebratulina latifrons Dall seems much wider, but this species is uncommon.

Following this review, Discradisca, Pelagodiscus, Terebratulina cailleti and the species of the genus Argyrotheca will be described more fully, supported by shell microstructural study; the distributions of all species will be plotted.

PRAGIAN-EMSIAN BRACHIOPOD COMMUNITIES OF THE FAOU FORMATION (MASSIF ARMORICAIN, FRANCE).

Rémy GOURVENNEC. Laboratoire de Paléontologie, UMR 6538 "Domaines Océaniques", Université de Bretagne Occidentale, Brest, France. (remy.gourvennec@univ-brest.fr).

The Faou Formation (Pragian-Lower Emsian) outcrops in the Seillou section (Massif armoricain, France) and consists in siltites, micaceous sandstones and decalcified limestones deposited in an

upper offshore open shelf environment. The rich, diversified fauna is dominated by brachiopods, crinoids and bryozoans. Relations between benthic assemblages, palynomorphs and sea-

level variations are currently under investigation. Three types of deposits have been recognized after their sedimentary structures, on a proximal-distal transect:

1- A proximal upper offshore environment showing long waves thick hummocky cross stratifications (HCS) and well marked erosive surfaces.

2- A median upper offshore environment characterised by short wave, thin HCS, erosive surfaces, furrowcasts, cogenetic in phase climbing ripples, graded rhythmites and silt laminae.

3- A distal upper offshore environment recognisable after the fine, turbiditic-like storm deposits.

Faunal assemblages have been identified along the section and are closely related to the types of deposits (i.e. to the environment and depth or distance to shoreline). From the distal to the proximal pole, we idenfied respectively:

1- The Uncinulus Community (U. subwilsoni, Adolfia sp., Schizophoria sp. and Anathyris, Leptostrophia, Stropheodonta and Alatiformia as accessory taxa). This community belongs to the BA3.

2- The Xana-Vandercammenina Community (Xana n.sp., V. trigeri and various spiriferids and orthids as accessory elements). This community belongs to the distal BA2.

3- The Orthid-Spiriferid-Terebratulid Assemblage (OST) that resembles the previous community but also yields Chonetids (up to 10%).

4- The Chonetid Assemblage that is dominated by Chonetids and Spiriferids, with some Orthids and Terebratulids as accessory taxa.

The Chonetid Assemblage belongs to the BA2. It should be noted that the entire section is characterised by the presence of the Chonetids that represent almost 60% of the total brachiopod fauna. The diversity increases towards the top of the section, due to the fact that several sea-level variations occurred in a short lapse of time, resulting in a succession of condensed levels. The proportions of reclined and attached forms (together with crinoids) vary along the section but do not seem to be closely related with the major changes in the environmental conditions.

Some index taxa can be used as indicative support for the identification of the environmental domains. For example Douvillina and Vandercammenina are restricted to the median upper offshore domain. Alatiformia is present only in the distal upper offshore environment, contrary to the Terebratulids s.l. that are almost completely lacking in this type of environment. Despite of the sedimentary condensation, the faunal assemblages are related to a bathymetric domain and have a predictive value.

PERMIAN BRACHIOPOD ASSEMBLAGES OF THE EASTERN EUROPE (TAXONOMY, BIOGEOGRAPHY, BIOSTRATIGRAPHY)

Tatjana A. GRUNT. Palaeontological Institute, Russian Academy of Science, Profsoyuznaya, 123, Moscow B-647, Russia. (1247.g23@g23.relcom.ru)

David A.T. HARPER¹ and Emma GALLAGHER². ¹Geological Museum, University of Copenhagen, Øster Voldgade 5-7, DK-1350 Copenhagen K, Denmark. ²Department of Geology, National University of Ireland, Galway, Ireland.

The basic architecture of the deltidiodont articulated brachiopod (strophomenates and early rhynchonellates) was established by the early Cambrian and diversified into a wide variety of

morphologies during the early Ordovician radiation, prior to radiations amongst the more advanced cyrtomatodont types. The deltidiodont division includes the pedunculate protorthides (early Cambrian — late Devonian), orthidines (mid Cambrian — mid Devonian) and dalmanellidines (early Ordovician - latest Permian). New classifications for the orthides, presented in the revised Treatise, are analysed using a number of tree metrics: The orthidine tree has a Stratigraphical Consistency Index (SCI), Relative Completeness Index (RCI) and a Gap Excess Ratio of 0.375, 78.79%, 0.83 respectively whereas the dalmanellidine tree has SCI, RCI and GER values of 0.35, 48.47%, and 0.395. The relatively low values of tree metrics for the punctate orthides partly reflects a less complete knowledge of dalmanellidine phylogeny.

Many orthide groups apparently originated and developed in shallow-water environments but radiated later into quieter, deeper-water niches or more specialised cryptic habitats during their phylogeny. The pattern of radiations suggest step-wise waves of diversification simulating ecological displacements by successive individual superfamilies within the Orthida and through the early Palaeozoic; peaks in diversity are matched by expansions in morphological disparity in the orthidines but this correlation is less clear in the dalmanellidines, where generic distinctions are less marked.

The initial early to mid-Cambrian radiation of the group apparently occurred at high latitudes; but during the early Ordovician radiation most orthide families had widespread distributions although the geographical ranges of genera were more restricted. Few of these deltidiodont taxa are represented in later Palaeozoic faunas; these survivors, for example Schizophoria (Enteletoidea) and Rhipidomella (Dalmanelloidea), continued as a minor part of cyrtomatodont and productide-dominated epifaunal benthos. Macroevolutionary divergences presumably during the mid to late Cambrian, reflected at the family level, were apparently decoupled from later generic diversifications during the Ordovician together with abundance patterns of species and ecological events within superfamilial taxa. This pattern continued during, for example, the mid Devonian and late Permian when local radiations generated a range of highly-specialized taxa.

David A.T. HARPER¹ and Linda HINTS². ¹Geological Museum, University of Copenhagen, Øster Voldgade 5-7, DK-1350 Copenhagen K, Denmark. ²Institute of Geology, Tallinn Technical University, Estonia pst. 7, 10143 Tallinn, Estonia.

The succeeding later Ordovician brachiopod associations were characterized by a marked spatial differentiation with both widespread and temporally constrained faunas such as the Holorhynchus (Pirgu Regional Stage) and the Hirnantia (Porkuni Regional Stage) faunas together with the more restricted Streptis fauna. During the early Ashgill the shallow-water facies was dominated by large-shelled brachiopods whereas in the deeper parts of the basin equivalents of the Foliomena fauna occur in red argillaceous rocks. The restriction of habitable areas for benthic faunas due to the end-Ordovician fall in sea level caused the rapid disappearance of existing shallow-water brachiopod faunas. Similar changes with degrees of variation occurred within the Swedish confacies belts and near the margin of the platform in the Oslo Basin.

HE Xi-Lin¹ and SHEN shuzhong². ¹Mineral Resources and Environmental Science College,

As we know, an extensive regression in the latest Permian (equivalent to the Changhsingian of China) extended over the world. At that time the European Continent, North America, North Asia, Africa and India developed widely lagoonal or red bed deposits. In these deposits, the normal marine fossils, as well as the brachiopods, experienced difficult living conditions.

South China marked the eastern Tethys and is also a large transgressive area in the Changhsingian of the latest Permian so that marine strata spread very widely. Here various marine fossils, including brachiopods, are very abundant.

We now find that the Changhsingian brachiopod faunas in South China include more than 300 species belonging to 37 families and 75 genera, including some newly identified genera and species. According to the present data at home and abroad, the Changhsingian brachiopod faunas in South China are the most abundant faunas in the Uppermost Permian of the world.

Based on the brachiopod evolutionary pattern, 3 assemblage zones may be recognized. They are listed in descending order as follows:

1. Waagenites pigmaea - notothyris crassa - neochonetes strophomenoides.

2. Prigeyerella costellata - Pellichia traversa.

3. Derbyia guangdongensis - Orthothetina eusakeos - Oldhamina squamosa.

Four brachiopod communities of the Changhsingian in South China are recognized. They are the Pettichia community, Oldhamina community, Paryphella - waagenites community and Pseudolabaia Ovatis community.

Kevin G. HELFENBEIN, Wesley M. BROWN, and Jeffrey L. BOORE. Department of Biology, University of Michigan, Ann Arbor, Michigan 48109-1048, USA.

With a few known exceptions, animal mitochondrial genomes range in size from 13-18 kb, contain 13 protein coding genes, 2 ribosomal RNA genes, 22 tRNAs and non-coding regions that presumably are involved in transcription and DNA replication. Thus on the one hand, metazoan mitochondrial genomes are large data sets with respect to potentially useful phylogenetic information, but are small genomes compared to microbial ones, making them more tractable for genome evolution studies.

The phylogenetic position of lophophorates–phoronids (a type of morphologically simple tube worms), brachiopods, and ectoprocts (bryozoans)–has long been controversial. We have sequenced the mitochondrial genomes of the phoronid Phoronis architecta and the articulate brachiopod Terebratalia transversa, and have analyzed the phylogenetic position of phoronids and articulate brachiopods in the metazoan tree using two mitochondrial data sets: amino acid sequences and gene arrangement. Additionally, comparison of the Terebratalia genome to that of two other completely sequenced articulate brachiopods yields interesting observations regarding evolution of nucleotide composition and non-coding/signaling DNA, and suggests that mitochondrial gene order may be phylogenetically informative for addressing phylogenetic questions within the articulate brachiopod clade.

Roger HEWITT¹ and Martin A.WHYTE^{2 1}12 Fairfield Road, Eastwood, Leigh-on-Sea, Essex, SS9 5SB, U.K.. ²Environmental and Geological Sciences, University of Sheffield, Dainton Building, Brookhill, Sheffield, S3 7HF, U.K..

X-ray diffractometers were used to separate amorphous from fine or disordered crystalline carbonate fluorapatites in Recent brachiopod shells. The hexagonal unit cell dimensions in Å and the apparent crystal sizes in nm had the following values in those Recent samples that represent fresh shell material with relatively small effects due to amorphous material. The latter were increased in Lingula and Glottidia shells that were soaked in sea-water for 14 months after death.

Sample Unit Cell Crystal Size

a c a c

Lingula anatina 9.371 6.868 19.3 43.1

Soaked equivalent 9.348 6.866 - -

Discinisca strigata 9.340 6.881 11.8 27.8

Glottidia pyrimidata 9.323 6.871 - -

Soaked equivalent 9.363 6.898 - -

Fossil brachiopods and more obviously diagenetic carbonate fluorapatites have lost the amorphous material, have crystal sizes with slightly enlarged dimensions (e.g. 25 to 65 nm for a in the brachiopods) and a larger c unit cell (6.886-6.900). The latter is due to replacement of Cl by F. Carboniferous Lingula and Mesozoic Glottidia and a disciniscid appear to have retained the a unit cell dimension of the soaked Lingula and the fresh shells with a higher F to OH ratio than Lingula. However, they also define a trend in which older brachiopods with similarly small crystals, have the larger a unit cell resulting from CO₂ loss in pure fluorapatite.

Norton HILLER. Canterbury Museum, Rolleston Avenue, Christchurch, New Zealand.

New Zealand’s well known Cenozoic brachiopod faunas have primarily been described from sedimentary rocks in Canterbury and North Otago, on the eastern side of the South Island. A newly discovered fauna, of mostly small individuals, is described here from Otaian (Early Miocene) deposits on the west coast of Northland, near the northern tip of the North Island. This fauna comprises some surprising elements that are not usually recorded from other New Zealand brachiopod faunas of the same age.

Taxa present include Neocrania, Calloria, Terebratulina, Thecidellina, Megerlina, and as yet undetermined terebratuloids and terebratelloids. The record of the kraussinoid Megerlina is a first for this genus in New Zealand.

Otaian brachiopods from the eastern South Island localities include members of the Rhyzothyris and so-called ‘Pachymagas’ lineages as well as Aetheai, Liothyrella, and Notosaria.

Thus it would seem that the two areas have few, if any, taxa in common. This situation is reflected in the associated molluscan faunas in which there is also little similarity between the two areas. Micropalaeontologists have also had problems in effecting correlations between the foraminiferal faunas of the two areas and attributed the differences to different temperature regimes. A warm water province existed in Northland, possibly extending along the present west coast of the South Island into southernmost New Zealand, and a temperate province existed in the Canterbury-North Otago region.

The brachiopod faunas therefore seem to support the notion of distinct faunal provinces within the Early Miocene of the New Zealand region.

Magdalena IORDAN. Geological Institute of Rumania, 1 Caransebes st., 78344 Bucharest 32, Romania.

The paper describes and reviews the Palaeozoic brachiopods from Carpathians and their foreland (Moldavian, Scythian and Moesian Platforms), including the North Dobrogea orogenic belt.

In the South Carpathians the presence of the Lower Silurian and Lower Carboniferous is attested by brachiopods. The brachiopod assemblage consisting of Orthids, Strophomenids, Pentamerids and Spiriferids indicate the Middle and upper Llandoverian age of the Valea Izvorului Formation. The cosmopolitan faunas suggest that this area correlates with England, Norway (the Oslo region) and Sweden (the Gotland region). The lower Carboniferous brachiopods including giant Productids and Spiriferids imply a Tournaisian age for the Valea Idegului Formation of the same Danubian domain.

The upper calcareous complex of the Moldavian Platform yielded a Silurian shelly fauna facies consisting mainly of brachiopods. The Wenlockian assemblage is characterized by the appearance of Plectambonitoids with the predominance of Leptaenids, lack of Protochonetids and nearly complete dissappearence of Orthids. The Ludlow-Pridoli-Gedinnian asesemblage is characterized by the appearance and predominance of Protochonetids, appearance of Spiriferids with predominance of Delthyrids and by the presence of Orthids. The paleontological assemblage proves the similarity with Podolian and Baltic faunas, as the Moldavian Platform represents the south-western margin of the East European Craton.

The Romanian part of the Moesian Platform is part of the Protomoesian microcontinent. In the detrital deposits of the Cambrian and Ordovician, only inarticulate brachiopods (Lingulellids and Acrotretids) were identified together with middle Cambrian trilobites, Ordovician graptolites and with palynomorphs. A graptolite shale facies was described in the Silurian, as well as a shelly fauna facies. Only the mixed type of the graptolite shale facies (Pridolian strata) yielded tiny brachiopods (Orbiculoids, Strophomenids, Spiriferids) and attests a Rhenish and Bohemian type of faunas. The shelly fauna facies, described only in the south-western part of the Platform, yieled a neritic shallow water paleontological assemblage characteristic for Wenlockian, Ludlowian and Pridolian. In the Devonian time, a rich faunal and floral assemblage was living in the basal argillitic facies (Gedinnian-Emsian) and in the middle gritty one (Eifelian), as much as in the upper carbonate-evaporite facies (Givetian-Famennian). The age indicator brachiopods (Lower Devonian), as well as the brachiopod zones (Middle and Upper Devonian), together with the entire palaeontological association attest a similarity with the Rhenish, Moravian, Barrandian and Turkish Devonian faunas.

The Carboniferous brachiopods indicate the presence of the Visean (giant Productids, Strophomenids, Spiriferids) and the Namurian-Westphalian (small Productids) and enable correlations with the Dinant and Namur areas of Western Europe as well as with the East European Platform and Poland.

In the North Dobrogea orogenic belt, Lower Devonian brachiopods were identified only in the western part, in the Macin zone. They are associated with crinoids, tentaculites and subordinately with trilobites, corals, bryozoans, ostracods and suggest a very shallow-water deposition in a benthic, open shelf environment. The macrofaunal assemblage correlates with the Ardennes and Rhenish Massif (Siegenian), as well as with Poland and Turkey.

THECIDEIDE PHYLOGENY, HETEROCHRONY, AND THE GRADUAL ACQUISITION OF CHARACTERS.

Glenn JAECKS, Dept. of Geology, University of California, Davis, CA. 95616 USA. (jaecks@geology.ucdavis.edu)

The classification of thecideide has been contentious: they have been included in the strophomenates, spire-bearers and terebratulides, all within the last three decades. Each of the evolutionary scenarios implied by these alternative classifications have been supported by emphasizing different character suites, shell microstructure and median septum morphology in particular. Most recently they have been afforded order status because they share few characters with any one group. While phylogenetic analysis has so far been little help in resolving this issue, it has provided a clearer picture of gradual character evolution within Thecideida. I analyzed the thecideides phylogenetically by constructing a matrix of 55 characters (some multistate, all unordered, equal weight) and up to 46 ingroup taxa (at least one per genus) and the program PAUP* to construct most parsimonious trees. Terebratulide, strophomenate, and spire-bearing outgroups were used, together and separately, to polarize the characters and root the trees. Trees constructed using the terebratulide outgroup differed from all other analyses in stratigraphic agreement and in composition of basal taxa. Most terebratulide-rooted trees had the Jurassic genus Eudesella basal, and many distal clades were stratigraphically inverted, with the oldest members in derived positions. Other trees placed many Triassic taxa, for instance Thecospira, at or near the root and showed good general agreement with the stratigraphic record. One common feature of all trees, supported by the presence of a broad median septum and ramuli, was the appearance of a derived Lacazella clade that includes many of the Lacazellidae. Phylogenetic results support current classification in a limited sense, but not all recognized families are monophyletic.

Characters often associated with Theideida appear piece-meal and are often homoplastic: the often basal thecideide, Thecospira, is smaller than most outgroup members, yet larger than most other thecideides, suggesting a gradual decrease in size. Likewise, Thecospira does not have a dorsal median septum as an adult, suggesting the acquisition of this character later in the group's history. The other prominent feature in thecideide evolution, the expansion of the shell primary layer (or reduction of the secondary layer), occurs in derived taxa, and may occur more than once. Both shell microstructure and median septum characters played were needed to resolve thecideide relationships, and both character suits are less homoplastic than average thecideide characters. Both thecideide size and secondary layer reduction have been attributed to heterochrony in the past. Although heterochrony may have been involved in the origin and evolution of the group, results do not support the thecideides as a paedomorphic group. Rather, the involvement of heterochrony was likely complex, affecting characters independently. For instance, the development of median septum ramuli and multiple anterior septa appear to have arisen independently several times, and are associated with relatively large body sizes, suggesting peramorphic processes.

Ulrich JANSEN. Forschungsinstitut Senckenberg, Frankfurt/Main, Germany.

Due to the aphoristic original diagnosis, the name Acrospirifer Helmbrecht & Wedekind 1923 (type species: Spirifera primaeva Steininger 1853) was misused to a world-wide scale for any large and strongly plicated Devonian spiriferid until the 1960‘s. In the course of modern investigations, it has become necessary to subdivide the genus in its former extent into many genera, e. g. Multispirifer, Arduspirifer, Dixonella, Patriaspirifer, Cumberlandina, Intermedites and Acrospirifer itself in a restricted sense. In the "treatise" (Pitrat 1965), Acrospirifer was restricted to forms with short free dental plates and lacking crural plates. Only considering materials from the Armorican Massif, Gourvennec (1989) published a revised diagnosis with capillate micro-ornamentation and lacking notothyrial platform as most important characters. However, Vandercammen (1963) had already recognized a fimbriate micro-ornamentation in materials from the type-region of the genus, but Gourvennec (1989) believed that Vandercammen was mistaken and the micro-spines being just a fallacious impression caused by "perturbations" of the capillae at the passage from one growth lamella to the next one. Subsequently, Carter et al. (1994), preparing the spiriferid part of the new brachiopod volume of the "treatise", revised the diagnosis of the family Acrospiriferidae Termier & Termier 1949 which included a capillate micro-ornamentation as main diagnostic feature. At last, Johnson (1995) erected a new genus Patriaspirifer differing from Acrospirifer by a fimbriate micro-ornamentation.

New investigations of well-preserved materials from the regio typica and stratum typicum (Rheinisches Schiefergebirge, Siegen-Schichten) by the author have clearly confirmed Vandercammen’s (1963) observation that Acrospirifer is characterized by the presence of micro-spines and a strongly developed notothyrial platform. The capillate forms with weakly developed or lacking notothyrial platform from W-Europe and N-Africa (group of "Spirifer" fallax Giebel 1858) are assigned to Filispirifer n. g. The family Acrospiriferidae sensu Carter et al. 1994 cannot be maintained any further. With respect to Patriaspirifer, it should be tested whether it is justified to maintain the genus.

This taxonomic odyssey could have been avoided if primarily type materials of the type species had been investigated and not exclusively allopatric specimens.

Jisuo JIN, Department of Earth Sciences, University of Western Ontario, London, Ontario, Canada, N6A 5B7 (jjin@julian.uwo.ca)>

The Lower Silurian (Llandovery) carbonate succession of Anticosti Island, eastern Canada, contains a rich and diverse suite of pentamerid brachiopods, with Virgiana, Pentamerus, stricklandiid, and Clorinda communities developed at numerous horizons in the Becscie, Merrimack, Gun River, and Jupiter formations. Detailed taxonomic study of large and extensive collections including thousands of specimens from several hundred localities reveals a number of evolutionary trends that are different from those shown by the Early Silurian pentamerid brachiopods in the UK and the Baltic region: 1) The middle-late Rhuddanian Virgiana Community, confined to Laurentia and Siberia, initially evolved in shallow and turbulent water environments and subsequently expanded into deep-water ramp and shelf settings; 2) The Pentamerus Community from the lower Goeland Member of the basal Jupiter Formation was adapted to living in deep-water and muddy-substrate conditions on a carbonate ramp and later evolved toward larger, globular shells in somewhat shallower waters; 3) Stricklandia in latest Rhuddanian-early Telychian strata lacks outer plates and cannot be correlated to the Stricklandia lens lineage of the UK and the Baltic region; major evolutionary trends shown by the Anticosti stricklandiid are the reduction of umbones into a chisel-edge-shaped shell posterior to produce the Microcardinalia stock and the development of various types of shell rugae and costae to produce the Chiastodoca and Ehlersella stocks; these morphological changes are interpreted to have been the result of stricklandiid adaptation to the generally low-energy, muddy-substrate environment of the Anticosti Basin; 4) Faunal, taphonomic, sedimentological and geochemical data indicate that there was considerable overlap in the water-depth ranges of the stricklandiid and the Pentamerus communities, and many large, laterally extensive stricklandiid communities lived at a shallower water depth than the Pentamerus Community; and 5) The Clorinda Community is considerably less common than the Pentamerus and the stricklandiid communities in the Anticosti succession, and one group, Clorinda (Phricoclorinda), developed concentric rugae in the posterior portion of the shell; this trend appears to be parallel to the evolution of Clorinda in the Baltic region. Whereas there appears to be a broad, water-depth-related zonation of the Virgiana, Pentamerus, stricklandiid, and Clorinda communities toward deeper water on the Anticosti carbonate ramp, a prominent anomaly in the evolution and depth range of the stricklandiids is characteristic of the Anticosti pentamerids when compared to the classic pentamerid communities and stricklandiid evolution of the British type area.

SILURIAN BRACHIOPODS OF THE TURKESTAN AND NURATAU RANGES, SOUTH UZBEKISTAN

Irina KIM¹, Michael G. BASSETT² and Leonid E. POPOV². ¹OAO ‘Regionalgeologiya’ Eshonguzar, Tashkentakaya Oblast, 702050 Uzbekistan. ² Department of Geology, National Museum of Wales, Cardiff CF10 3NP, Wales, U.K.

Within the South Tien Shan orogenic belt, the richest known Silurian (Wenlock — Péídolí) brachiopod faunas occur in the Nuratau and Turkestan ranges of South Uzbekistan. Work in progress recognises over 60 species assigned to 41 genera. Older Silurian (Llandovery — early Wenlock) facies are mostly graded siliciclastic and pyroclastic deposits with interbedded graptolitic mudrocks, formed on slopes within an intraoceanic island arc, but from the mid Wenlock carbonate sedimentation became widespread on shallow island shelves. Complex bottom topography led to well-defined ecological differentiation of brachiopod faunas.

Shallow shelf facies of the Merishkor Regional Stage (late Wenlock) contain a distinctive medium diversity assemblage dominated by Molongia in association usually with Leptaena, Atrypoidea, Nalivkina, Janius, Spirinella and rare Conchidium; this fauna is assigned to Benthic Assemblage (BA) 2. Conchidium also occurs separately as almost monotaxic clusters of conjoined valves and coquinoid accumulations on the flanks of organic build-ups (BA 3). Offshore shelf facies contain BA 4 associations of Isorthis, Dicoelosia, Clorinda, Ancillotoechia, Atrypoidea, Gracianella, among others. There is a marked faunal turnover across the Wenlock —Ludlow boundary, involving the disappearance of Nalivkinia, Janius and Spirinella and the first occurrences of such genera as Brooksina, Gypidula, Severella, Decoropugnax and Alaskospira. The early Ludlow shallow shelfbrachiopd fauna of the Kurgan Region Stage (BA 2-3 is dominated by Conchidium, replaced offshore (BA 4-5) by medium to high diversity associations with Brooksina, Skenidioides, Dicoelosia, Gypidula, etc. There is then a notable diversification of brachiopods in the late Ludlow and Péídolí (Tamcha and Rabkash regional stages), marked in particular by the appearance of Iridistrophia, Telinotoechia, Tadschikia, Gracianella, Spinatrypa, Atrypina, Nikiforovaena, Eoreticularia, Proreticularia and Protathyris. Shallo water assemblages (BS 2) from that interval usually include Atrypoidea and Tadschikia, while organic build-ups support medium to high diversity faunas of pentamerides, atrypides and athyridides.

Most Wenlock genera from the region have wide geographic ranges, although the presence of Nalivkinia suggests biogeographic linkage with North China, Kazakhstan and Altai. Biogeographic discrimination of the later Silurian South Tien Shan faunas is more evident, with some endemic species and genera such as Retziella, Tadschikia and Nikiforovaena; indicate a clear affinity with the Sino-Australian Province, although, some of the most typical genera from that area has not yet been identified in Uzbekistan.

Daphne E. LEE¹ and C.H.C. BRUNTON². ¹Geology Department, University of Otago, P.O. Box 56, Dunedin, New Zealand. ²Department of Palaeontology, The Natural History Museum, Cromwell Road, London SW7 5BD, U.K.

Terebratula terebratula (Linnaeus 1758), the name-bearer for the Order Terebratulida, Phylum Brachiopoda, has a long and complex history. The specimen now recognised as the type was first illustrated by Colonna in 1616, and the species Anomia terebratula, based on the Colonna figure, was described by Linnaeus in 1758. Fabio Colonna, born in Naples in 1567, was, like Galileo, a member of the Accademia dei Lincei, and was one of the first natural scientists to look at fossils in a biological context. Terebratula was established as a genus by Müller in 1776, and Anomia terebratula designated as the type by Lamarck in 1799, although it was not an originally included nominal species. In spite of this distinguished patronage, the type of the genus was never formally ratified; the whereabouts of the type was unknown; and the age and exact position of the type locality was uncertain. Two centuries after its original designation, Anomia terebratula is officially accepted as the type species of the genus Terebratula. We have collected new material from Colonna's rediscovered type locality, a calcarenite of Pliocene age, near Andria, Italy, and selected a neotype for Terebratula terebratula. We re-evaluate the late Cenozoic species assigned to Terebratula, and offer possible explanations for the extinction in the Pleistocene of this once widespread genus.

Daphne E. LEE¹, Sandra. J. CARLSON² AND Nancy BUENING^{2. 1}Geology Department, University of Otago, Box 56, Dunedin, New Zealand. ²Geology Department, University of California, Davis, California 95616, USA

Generic distinctions within short-looped brachiopods included in the Suborder Terebratulidina are based principally on differences in the loop and cardinalia. Morphological variation in the internal structures of 140 adult individuals belonging to two species of Recent brachiopods, Liothyrella neozelanica Thomson from New Zealand, and Liothyrella uva (Broderip) from South Orkney Islands is illustrated and demonstrated quantitatively. Considerable within and between species variation is present in each of eleven measured parameters (e.g. loop angle; ratio of loop length to width; position of crural processes) which have been previously used as key characters in establishing generic diagnoses in both Superfamily Terebratuloidea and Superfamily Loboidothyridoidea. This study clearly demonstrates the need for morphological studies of variation in both internal and external characters of large, representative populations or fossil assemblages before meaningful generic discrimination can be achieved.

Daphne E. LEE¹ and Murray GREGORY². ¹Department of Geology, University of Otago, Box 56, Dunedin, New Zealand. ²Department of Geology, University of Auckland, Private Bag, Auckland, New Zealand.

Brachiopods form a small but significant component of the deep-sea benthos in all oceans. Nearly half of the 40 brachiopods so far described from abyssal depths (>2000m) are short-looped species within the superfamilies Terebratuloidea and Cancellothyridoidea. A new genus and species of cancellothyrid brachiopod (Family Chlidonophoridae; Subfamily Eucalathinae), is described from cryptic habitats within lava caves in glassy basalt on the axis of the Southeast Indian Ridge, Indian Ocean. The small, punctate, strongly ribbed, highly spiculate brachiopods occur at depths of 3860m and 4900m and are primary colonisers on the volcanic substrate. Related species are recorded from depths of 2710m - 4851m in the southeast Pacific Ocean. Brachiopods are not reported from the much-studied, but patchy and ephemeral hydrothermal vent faunas of the mid-ocean ridge systems. However, they may be among the most widespread members of a poorly known fauna of attached, suspension-feeding epibionts on the rarely sampled, hard, basalt substrates of the mid-ocean ridge system (submarine superhighway) which forms the most extensive and continuous, essentially uniform habitat on Earth.

Marie LEGRAND-BLAIN. Institut EGID, Bordeaux 3 University. Allée F. Daguin, 33607 Pessac, France. (legrand@egid.u-bordeaux.fr).

The Morvan area, at the NE edge of the French Massif Central, lies in the internal Variscan belt. During the Famennian, a sporadic volcanic activity deposited pyroclastic flows interbedded in submarine muds. The volcanoes are believed to have erupted in an island arc.

The marine sediments : thick dark siltstones (with local small current ripples) were deposited on quiet sea floors. They are nearly barren of bioturbation, and yield few fossils.

A locality near Bourbon-Lancy : Pont du Vezon = "Moulin du Roi" (Michel-Levy 1909) has been reviewed. Sparsely fossiliferous mudstones are interbedded between volcanic flows and contain a thin cinerite bed. Clymenid Cephalopods and Trilobites indicate a precise Strunian age : upper Wocklumeria zone, below the "Hangenberg event". Entomozoid Ostracods characterize dysaerobic environments (Legrand-Blain et al., 2000). Associated fossils are Plant fragments, Conularids, Bivalve fragments.

The Brachiopods, examined with the help of Denise Brice (Lille) are external-internal moulds of : - the Rhynchonellid Araratella (?), 2 ventral valves ; - the Athyridid Tulathyris (?) sp., relatively abundant conjoined valves ; - the Spiriferids Cyrtiopsis sp., Rigauxia sp., ventral valves only, all very small (4-8 mm).

Very few data on the effects of volcanic activities on marine faunas are available in the litterature. Small brachiopods may grow and be quickly buried in volcanogenic sediments (Lockley, 1990). The interpretation of the Brachiopods in the Morvan studied locality is : a peri-insular muddy substrate, open towards the ocean (Cephalopods) yields the athyrids and rhynchonellids, all of normal size. The small spiriferids come from a neighbouring volcanogenic substrate.

Svetlana V. LOBACHEVA. ALL-Russian Geological Institute (VEGEI), St. Petersburg, Srednyi pr. 74, 199106, Russia. (vsegei@mail.wplus.net)

Cyclothyridids are widespread in Cretaceous deposits and account for the majority of the Cretaceous rhynchonellids. They represent a rather primitive and conservative lineage in the evolution of the Order Rhynchonellida. It probably started from the Paleozoic Trigonirhynchiidae McLaren, 1965, and has morphological features that are difficult to recognize.

Cyclyothyrididae comprises rhynchonellids with a multicostate shell (costae starting from the umbo), raduliferal and canaliferal crura - without septalium and septal plates.

The composition of the family is debatable due to the difficulties in diagnosing the generic taxa of these rhynchonellids (Ager, 1965; Ager, Childs & Pearson, 1972; Makridin, 1964, etc.). In the process of studying the Jurassic genera, earlier assigned to cyclothyridids, many of them (Capillirhynchia, Formosorhynchia, Rhactorhynchia, etc.) were eliminated from the composition of this family (Childs, 1968; Kamyshan, Babanova, 1973, etc.). The material on the Early Cretaceous cyclothyridids of the Crimea, Northern Caucasus and Central Asia (Mangyshlak, Tuarkyr, Kubadag, Greater and Lesser Balkhan, Kopetdag, Gissar and Kyzylkum), revision of the published and collection data, enabled such morphological features to be traced, such as the structure of tooth and hinge plates, the presence of septum, pedicle collar and pseudoarea, character of the umbo, ribbing and number of costae, as well as the degree of development of the sinus and fold in these brachiopods. The conducted research enabled the generic range of this family, its geographic and stratigraphic range, to be analyzed and the composition of the therein comprised genera to be specified: Cyclothyris M’Coy, 1844 (Hauterivian-Turonian), Belbekella Moisseev, 1939 (Berriasian-Barremian), Sylcirhynchia Burri, 1953 (Hauterivian-Albian), Burrirhynchia Owen, 1962 (Aptian-Albian), Septatoechia Lobatscheva & Titova, 1977 (Aptian-Maastrichtian) and Cretirhynchia Pettitt, 1950 (Late Cretaceous).

The first Cretaceous representative of cyclothyridids probably originated from the Jurassic Tetrarhynchiidae Ager, 1965. In the Berriasian, the genus Belbekella appeared, and it coexisted with the last Praecyclothyris and Septaliphoria. In the Valanginian and Hauterivian, the genera Cyclothyris, Sulcirhynchia, Lamellaerhynchia appear; in the Aptian, Burrirhynchia and Septatoechia; in the Late Cretaceous, Cretirhynchia.

Cyclothyridids are also known from the Cretaceous of England, France, Switzerland, Spain, Italy, Belgium, Germany, Poland, Chechia, Slovakia, Romania, Yugoslavia and Bulgaria. Stratigraphically, they are apparently restricted to the Cretaceous system and occur only in sections of the Mediterranean and Middle European paleobiogeographic areas.

Alan LOGAN¹ and Sarah LONG^{2. 1}Centre for Coastal Studies and Aquaculture, University of New Brunswick, Saint John, N.B., E2L 4L5, Canada. ² Department of Palaeontology, The Natural History Museum, Cromwell Road, London, SW7 5BD, U.K..

The cementing inarticulate brachiopod Neocrania anomala (Müller 1776) is commonly found attached to hard substrates mainly in shallow cryptic habitats in the eastern North Atlantic. Its counterpart in the Mediterranean has previously been regarded either as a synonym, variety or subspecies of N. anomala or as a separate species N. turbinata (Poli 1775), the differences being mainly in the degree of calcification of the valves and the relative development of the dorsal valve muscle scars. Comparison of eastern North Atlantic collections from the Firth of Lorne (Scotland), Atlantis Seamount, São Tiago (Cape Verde) and Sagres (Algarve, Portugal), with Mediterranean collections from Tarifa Island (southern Spain, Straits of Gibraltar), Banyuls, Marseille (southern France), Corsica-Tyrrhenian Sea, Prvíc (Croatia), Malta, Zembra Island (Tunisia) and the Aegean-Lebanon Israel area indicates that there are basically two morphotypes, which, where they occur together, are quite distinct. One is characterized by a lightly calcified shell, conical dark-brown dorsal valve, subdued anterior adductor scars, prominent brachial protractors divided medially, and distinct brachial retractors, and is the typical N. anomala of the northeastern North Atlantic but also occurs in the Mediterranean at Banyuls, Corsica-Tyrrhenian Sea, Malta, Zembra Island, and the Aegean area. The other, characterized by a more heavily calcified shell, less conical light-brown dorsal valve, raised anterior adductor muscle scars, obscure brachial protractor scars on a spike-like ridge, and indistict brachial elevator scars, occurs at Tarifa Island, Marseille, Prvíc, Malta, Zembra Island and the Aegean-Lebanon Israel area and is regarded here as N. turbinata. This form is also present in the southeastern North Atlantic in Cape Verde and off the west coast of Africa. There is thus no morphological cline between anomala in the west and turbinata in the east in the Mediterranean, as previously suggested. Neither the shell morphology nor geographical distribution of the two forms appears to be the result of ecological factors, such as depth or hydrodynamic action.

Sarah LONG, Dept of Palaeontology, The Natural History Museum, Cromwell Road, London SW7 5BD, UK. (sll@nhm.ac.uk)

Since 1753 when the sale of Sir Hans Sloane’s Collection to the Crown resulted in the founding of the British Museum, many stunning specimens and manuscripts have been donated to what is now The Natural History Museum. Some of these materials relating to the Earth Sciences, Oceanography and Zoology will be on display during the Congress. This presentation is designed to compliment that display and in particular to look at the history of the Recent brachiopod collection.

The Recent brachiopod collection at the Natural History Museum represents an unique and historically important collection. The provenance of some specimens can be traced back into the eighteenth century. However, many of the specimens were either purchased or donated in the nineteenth century and were collected or described by leading conchologists and biologists of the time, such as Hugh Cuming, W. J. Broderip and Thomas Davidson. The nineteenth century was an exciting time for natural sciences and especially oceanography and this is reflected in the wealth of publications dating from this period. Using contemporary letters and diaries this presentation looks at those who contributed to the N.H.M. collection as well as some of the specimens they collected and described.

C. LÜTER. IBLS, Molecular Genetics, University of Glasgow, Pontecorvo Building, 56 Dumbarton Road, Glasgow, G11 6NU, Scotland, U.K.

Marginal setae, emerging from epidermal infoldings (setal follicles) of both the ventral and dorsal parts of the mantle, are one of the most striking characters of external adult brachiopod morphology. Setae also occur in lecithotrophic larvae of craniids and all articulate brachiopods (except thecideidines). Here, they are arranged in three (craniids) or two (articulates) pairs of bundles, originating fromm setal sacs. During or immediately after metamorphosis the larval setae are supposed to be shed and replaced by the marginal setae of the adults. As has been shown (Lüter, 2000) adult and larval setae can easily be distinguished by the arrangement of the seta-forming chaetoblast and the adjacent epidermal cell(s). Ultra-structural examinations of early developmental stages of Discinisca cf. tenuis (Sowerby, 1847) show that the first-appearing ‘embryonic setae’ (Chuang, 1977, 1990) in discinids are larval setae, almost identical to larval setae in craniids and articulates, and different to marginal setae of adults. These ‘embryonic setae’ occur as a pair of bundles before the discinid embryo hatches from the vitelline membrane. The hatching stage is lecithotrophic (but see Freeman, 1999), hence discinids, craniids and articulates all have larval setae during a lecithotrophic developmental phase. Thus, the hypothesis of a biphasic life cycle with a lecithotrophic pelagic larva and a planktotrophic benthic adult would provide the most parsimonious explanation for the ancestral brachiopod condition. The lack of lecithotrophic larvae in lingulids, therefore, is regarded as a derived character (see also Lüter, 1997) supporting the hypothesis that the planktotrophic developmental stages of organo-phosphatic shelled inarticulate brachiopods represent ‘pelagic juveniles’ rather than larvae (Long & Stricker, 1991).

David I. MACKINNON. Department of Geological Sciences, University of Canterbury, Christchurch, New Zealand.

The present-day global distribution of brachiopods of the Superfamily Megathyridoidea in mainly shallow, tropical and near tropical waters of both hemispheres points to a long and successful evolutionary history. They are typically small to minute in size and commonly occupy cryptic habitats such as the undersides of coral heads or the roofs of caves. The stratigraphically oldest megathyridoid taxa yet reported are four micromorphic species, referable to three genera (Praeargyrotheca, Evargyrotheca and Krimargyrotheca) from Lower Cretaceous (Berriasian) bryozoan-rich bioherms in Crimea, Ukraine.

Up to now, the ancestry and evolutionary origins of megathyridoid brachiopods has proven elusive. However, during the course of routine museum examination of material in connection with the brachiopod Treatise revision, a strong morphological resemblance (suggesting a significant new phylogenetic link) was noted between the western European Jurassic kingenoid, Trigonellina pectunculus (von Schlotheim, 1820), and one of the Lower Cretaceous megathyridoid species, namely Praeargyrotheca hexaplicata (Smirnova, 1972). Although differing in modal size by at least a factor of four, there are strong similarities between the two taxa in overall shape and foramen characteristics, and particularly in the form, frequency and developmental sequence of the dorsoventrally coincident plicae, the prominence and regularity of comarginal growth lamellae, and in granular microornament. The ventral valve interiors of both taxa exhibit a well-developed pedicle collar and a ventral median septum: dental plates are present only briefly during the ontogeny of Praeargyrotheca but are present through to adulthood in Trigonellina.

The main differences between the two taxa, apart from adult size, are to be found in the dorsal interiors, especially in the nature of the brachidium. Whereas the loop of Trigonellina is diploform, the loop of Praeargyrotheca is axial with a triangular, bladelike median septum and arcuate ribbons of descending lamellae extending from laterally deflected crura to the valve floor in typical megathyridoid fashion. Unfortunately, no Trigonellina juveniles of a size comparable to adult specimens of Praeargyrotheca were available in collections studied thus no direct comparison of loop configurations in the two genera at comparable size could be made. However, in the modern kingenoid Ecnomiosa, as well as the modern zeilleriod Macandrevia, the axial stage of loop ontogeny in juvenile specimens around 2 mm in length is associated with the development of long slender descending loop branches of megathyridoid appearance. Admittedly the phylogenetic links between Trigonellina and either Ecnomiosa or Macandrevia are tenuous, however the existence in the latter two taxa (whose affinities lie with two of the dominant Mesozoic long-looped superfamilies, the Kingenoidea and Zeilleriodea) of megathyridoid-like early loop configurations serves to reinforce the likelihood that similar early loop configurations existed in at least some Mesozoic long—looped taxa.

Taking account of the known stratigraphic ranges of both Trigonellina and Praeargyrotheca and their presumed adult (sexually mature) morphologies then a strong case may be made for considering the transition an example of heterochrony, most probably the paedomorphic process of progenesis (i.e. precocious sexual maturation). Given the morphological disparity between Praeargyrotheca and the two other sympatric megathyridoid genera (Evargyrotheca, Krimargyrotheca) the question arises as to whether or not the latter genera might not also be paedomorphic derivatives of separate, larger, Jurassic ancestors. If proven, then the Superfamily Megathyridoidea, as presently constituted, would be a paraphyletic clade.

Anna MADISON¹ and Madis RUBEL². ¹Palaeontological Department of the Geological Faculty, Moscow State University, Vorob’evy Hills, Moscow 119899, Russia. (nomadison@yahoo.com). ²Institute of Geology, University of Tartu, Vanemuise 46, Tartu 51014, Estonia. (rubel@ut.ee).

The Early to Middle Ordovician endemic Baltica Plate Lycophoria Lahusen 1885 is revised using collections from Sweden, Estonia, and Russia .Thus the type species L. nucella has been correctly identified over the whole area and the previously suggested lineage from L. nucella to L. globosa has been evaluated, as has its use in the correlation of sections. Evolutionary relationships are reviewed and a new species suggested. The stratigraphic distribution of all five species of the genus are tied to trilobite biozones used widely in the regional (chrono)stratigraphy.

The detailed study of Lycophoria shows that its cardinalium has a high bilobed cardinal process merged with stubby brachiophore plates, with a thickening before the sockets (fulcral plates). SEM study shows the Lycophoria shell is two-layered, the inner layer is fibrous and porous with endopunctae. This resolves the widely discussed systematic position of Lycophoria and it is included within the dalmanellidines within the Orthida. The Orthida was proposed by Williams and Harper (2000) as equivalent to the Rhynchonellida, Strophomenida, Pentamerida and others.

Miguel O. MANCEÑIDO. Invertebrate Palaeontology Department, La Plata Natural Sciences Museum, Paseo del Bosque, La Plata 1900, Argentina. (miguelma@mmance.cyt.edu.ar).

Crura are one the most distinctive skeletal structures from the dorsal valve interior of the Rhynchonellida, and they have often been regarded as important features for the classification of Mesozoic and Cainozoic representatives of this brachiopod order.

Initially only three kinds of crura were named and described. Starting from that basic descriptive triad, as a result of the subsequent development of their knowledge during the last century or so, more than twenty additional terms have been coined. The present contribution is a reappraisal aimed at systematizing and clarifying such complex terminological situation. For that purpose, distinction of better-characterized, simpler units which may be meaningful from the evolutionary viewpoint is emphasized. Four main groups of cognate crural types are thus recognized, with due regard to structural and cross-sectional variation, as follows:

ARCUAL Group: includes arcuiform, spinuliform, besides distally expanded and spiculated variants, and possibly also the so-called clivuliform type.

SEPTIFAL Group: comprises falciform, subfalciform, hamiform (= ex prefalciform), septiform types, and certain modifications either structural or of their distal end.

RADUCAL Group: includes raduliform, calcariform, canaliform types, as well as different variations of their cross section and of their distal end.

ENSIMERGAL Group: comprises mergiform, submergiform (= ex terebratuliform), ensiform, maniculiform, and perhaps also ciliform types.

Finally, the taxonomical significance and distribution of each of those groups in the various rhynchonellide superfamilies are summarily reviewed, with reference to the classificatory framework currently being adopted in the revision of Part H (Vol. 4) of the Treatise on Invertebrate Paleontology.

Miguel O. MANCENIDO¹ and Ellis F. OWEN ¹La Plata Natural Sciences Museum, Paseo del Bosque, La Plata 1900, Argentina, (miguelma@mmance.cyt.edu.ar). ²Natural History Museum, Cromwell Road, London SW7 5BD, U.K., (ellis.owen@talk21.com).

A major systematic revision of Mesozoic and Cainozoic Rhynchonellida based on generic diagnostic characters, and their geographical and stratigraphical distributions, resulted in the classification adopted in the new Treatise, which comprises 24 families grouped into 7 superfamilies: Dimerelloidea, with subcircular, discoidal to ventribiconvex, smooth to ribbed shells, reduced deltidial plates, and ensimergal crura, usually occur near ancient oceanic cold seeps. After a moderate Late Triassic radiation (3 families), one subfamily reached the Early Cretaceous and vanished shortly thereafter. Yet, extant Cryptoporidae appeared (paedomorphically ?) by Late Cretaceous and survived in deep seas. Norelloidea, with small, smooth to capillate, ovoid, depressed to dorsally sulcate shells, having tiny beaks and arcual crura, are a persistent stock with variably developed dorsal septum and septalium. Norellidae radiated largely in Early to Mid Triassic; of 7 subfamilies, one reached the latest Jurassic and another lingered until the Turonian, whereas Ochotorhynchiidae were just a minor offshoot. During Tertiary to Recent 2 families are known, Frieleiidae (3 subfamilies, mostly from bathyal to abyssal refugia) and extant Tethyrhynchiidae (minute submarine cave-dwellers). Pugnacoidea, with smooth to pauci-semicostate subtriangular shells, having divided hinge plates and septifal crura, show an early evolutionary dichotomy, already established by the Carnian (but probably older). Thus 3 Basiliolid subfamilies coexisted over most of the Jurassic-Cretaceous, one extended until the Barremian, another until the Eocene, and the main one still lives off-shore; a further Tertiary radiation involved other 3 subfamilies, one surviving in the bathyal West Pacific. After the Triassic, 3 subfamilies over most of the Jurassic attest to the Erymnariidae diversification, which culminated with the Erymnariinae between Cenomanian and Eocene. Lingering representatives of 6 Palaeozoic lineages died out along Late Triassic—Mid Jurassic times; 4 of them belong to Wellerelloidea, whereas the Rhynchotetradoidea include 2 Mesozoic families of flabelliform, planareas-bearing shells which have lost the sessile spondylium and lateral buttresses of their Palaeozoic ancestors. Rhynchonelloidea s.s., with subtriangular to cynocephalous, partly or fully costate, uniplicate shells bearing dorsal septum, uncovered septalium and raducal crura, died out at various stages during the Cretaceous. Rhynchonellidae radiated during Mid Triassic to Early Jurassic, adding 6 subfamilies to 2 long-ranging stem groups (Rhynchonellinae and Piarorhynchiinae), whereas Acanthothirididae comprise 2 spinose subfamilies (differing in reduced septum/septalium and details of crura). Hemithiridoidea, with subpentagonal to globose, commonly costate, uniplicate shells, bearing variably developed dorsal septum, uncovered septalium, squama/glotta and raduliform to canaliform crura, contain most "ordinary-looking" rhynchonellides. Tetrarhynchiidae radiated in Early to Mid Jurassic, adding 3 subfamilies to Tetrarhynchiinae. Towards the end of the Early Cretaceous, Tetrarhynchiidae gave rise to 2 subfamilies which spanned the rest of the Cretaceous and were replaced during the Eocene by extant Hemithiridae. Mid-Triassic Triasorhynchiidae, a minor early stock, might be superfluous if alleged lack of dental plates is a preservational artifact. Conversely, Mid Jurassic Septirhynchiidae form a distinctive offshoot with ventral median septum and recurved cardinal process. Cyclothyrididae are based on another long-ranging subfamily from which 2 smaller ones branched off in the Middle Jurassic, and which probably gave rise to modern Notosariidae towards latest Cretaceous.

INTERNAL STRUCTURES OF TRIASSIC SPIRIFERIDS BY S.E.M ANALYSIS

Nadia MANTOVANI. Dipartimento di Scienze della Terra,Via L. Mangiagalli, 34, 20133 Milano, Italy.

The ultrastructure of internal characters of four genera and ten species of Middle-Upper Triassic Spiriferids has been performed by S.E.M. analysis. The analysed Spiriferids, collected from the alpine and mediterranean areas, are: Mentzelia mentzeli mentzeli, Mentzelia mentzeli judicarica, Mentzelia ampla, Mentzelia propontica, Mentzelia ptychitiphila, Mentzelia palaeotypus, Koeveskallina koeveskalyensis, Koeveskallina validirostris, Tethyspira persis and Punctospirella fragilis.

The S.E.M. analysis allowed to observe, the flow of secondary fibres of dental plates, adminicula and dental flanges, the cardinal process, crura and crural flanges, both revealing the inadequacy of the classic morphological analysis and enhancing the taxonomic value of the obtained data. Owing to the observations carried out, only the two sub-species Mentzelia mentzeli mentzeli and Mentzelia mentzeli judicarica have been included in the genus Mentzelia and have been raised to rank of species. The latter are in fact characterised by the occurrence of dental plates either diverging on the ventral valve floor or ankylosed to the ventral median septum. The latter is long, with lanceolate shape and characterised by a median dichotomy, where secondary fibres loose their individuality, both because of coalescence phenomena and re-crystallisation. Dental flanges are apically fused to the median septum, developing a small spondylium. In Mentzelia mentzeli mentzeli, the median septum enters the spondylial chamber only apically, whereas it doesn’t enter at all in the Mentzelia mentzeli judicarica. The ultra-structural analysis of internal characters of Mentzelia ampla, M. propontica and M. ptychitiphila (often indicated in literature as "Mentzelie with costae") and the external characters morphological analysis, brought to light the necessity to include them in a new genus. These three species are in fact characterised by dental plates, from apically arranged to well developed and never ankylosed to the ventral median septum, and by dental flanges from converging to diverging to the ventral valve floor. The dental flanges are fused with the median septum developing an apical spondylium. In the species ampla, the median septum enters deeply the spondylial chamber, whereas in the propontica and ptychitiphila it enters only by its apical part.

Mentzelia palaeotypus is placed in another new genus, on the basis of its external characters and morphological/ultra-structural analysis of the internal structures. This species differs from Mentzelia by its ornamentation of numerous and fine costae on the entire surface of both the valves and by its well-developed sulcus and fastigium. With regard to the internal characters, palaeotypus shows dental flanges converging to the median septum and joining it by a transversal structure, developing an apical spondylium where the septum enters only apically; it does not show dental plates.

Finally, the morphological analysis of the external characters and the morphological/ultra-structural analysis of the internal characters of the genera Koeveskallina and Tethyspira, together with those of Mentzelia-like species, have allowed to discuss their super-generic taxonomic position, integrating the classifications proposed by Carter et al. (1994) and Dagys (1996).

RUGOSOCHONETIDAE FROM THE CARBONIFEROUS OF THE CANTABRIAN MOUNTAINS (N. SPAIN)

M. L. MARTÍNEZ CHACÓN¹ & C. F. WINKLER PRINS². ¹ Departamento de Geología, Universidad de Oviedo, Arias de Velasco s/n, E 33005 Oviedo, Spain. (mmchacon@asturias.geol.uniovi.es). ² Nationaal Natuurhistorisch Museum, Postbus 9517, 2300 AR Leiden, The Netherlands. (winkler@nnm.nl).

An overview will be given of the many species belonging to the family Rugosochonetidae known from the Carboniferous (Tournaisian-Kasimovian) found in the Cantabrian Mountains. They are compared with other occurrences in Eurasia and elsewhere, thus providing their stratigraphic and geographic range. The implications with regard to plate-tectonic reconstructions and palaeoecological conditions will be discussed. As an example, the possible connection with Gondwana in general, and Argentina in particular, will be considered. Another interesting case is a comparison with an Atokan fauna from the Hare Fiord Formation of Ellesmere Island (Canadian Arctic Archipelago).

The subfamiliar and generic content of the Rugosochonetidae will be discussed in some detail, as well as the relation between Rugosochonetes and Neochonetes (as a result some species will be reassigned). A new subfamily, belonging to a separate lineage of the Rugosochonetidae is to be published elsewhere together with some new species of Neochonetes.

Michal MERGL. Dept. of Biology, Pedagogicka Fakulta, Klatovska 51, Plzen 306 19, Czech Republic. (mmergl@kbi.zcu.cz).

Organophosphatic (= lingulate) brachiopods of Silurian and Devonian age are not well known, unlike lingulate brachiopods of the Cambrian and Ordovician. They are generally referred to a few genera of the families Obolidae, Pseudolingulidae, Trematidae, Discinidae and to four families of the Acrotretida.

A study of lingulates from the Silurian and Lower-Middle Devonian limestones (Mergl, in press) has found that the stratigraphical ranges of some lingulate families are much more extended than formerly realised. Some families suggested to have become extinct within the late Ordovician glaciation-related event, or persisting only to the early Silurian, have been observed in much younger horizons (in Lower Silurian or Lower-Middle Devonian, respectively).

Paterinids are known from Early Cambrian to late Ordovician, however, the tuffaceous limestone of the elkovice Formation (Llandovery, Aeronian) yielded minute fragments of phosphatic shell which bear the typical pitted, divaricate ornament of late paterinids (Dictyonites). The Paterulidae appeared in the late Arenig and with little morphological change persisted to the Pragian (Jaeger & Wolfart, 1969). In the Barrandian the morphologically typical paterulid Paterula holynensis has been discovered at the early Middle Devonian, in black bituminous limestone embedded in black shales of early Eifelian age.

The Dysoristidae, a family generally referred to the order Lingulida, are considered as a short-time ranging and taxonomically poor family known from the Upper Cambrian to the Arenig. However, the undoubted remains of a new dysoristid has been recovered from the late Pragian limestone in the Barrandian.

The Acrotretidae, one of four acrotretid families extending into the Silurian, is represented by the genus Acrotretella in Bohemia. The youngest species A. triseptata is known from the early Lochkovian, extending its range into the early Devonian.

The Siphonotretidae has been restricted to Cambrian and Ordovician rocks but four distinct species, which belong probably to all three subfamilies (Siphonotretinae, Schizamboninae, Acanthamboninae) are known from the Silurian and Lower Devonian. The youngest member occurs only a few metres below the Lower/Middle Devonian boundary in the parastratotype of the Lower /Middle Devonian boundary (Praha — Holynõ, Prastav Quarry).

All families newly recovered are represented by minute species. The Siphonotretidae, Dysoristidae and Paterulidae indicate shell miniaturisation during phylogeny of the groups which may be connected with respiration in oxygen-deficient waters, since siphonotretids, dysoristids and paterulids are known from the deep-water environment marginal to dysaerobic waters of the graptolitic biofacies.

Neda MOTCHUROVA-DEKOVA. National Museum of Natural History, 1 Tsar Osvoboditel blvd, Sofia 1000, Bulgaria.

A comparative microstructural SEM analysis has been carried out on fifty transverse shell sections from thirty-four species belonging to nine Cretaceous rhynchonellid genera, with emphasis on the Late Cretaceous representatives. The purpose of the investigation is to describe the shell microstructure and find new data, clarifying the possibility of using them as an additional criterion in the taxonomy of the Late Cretaceous rhynchonellids. Depending on the material available, some genera have been investigated in detail (Cretirhynchia, Cyclothyris, Orbirhynchia, Septatoechia) and others have been examined for comparison only (Almerarhynchia, Belbekella, Burrirhynchia, Grasirhynchia).

All the studied rhynchonellid shells are impunctate and composed of two calcareous layers: microcrystalline (primary) and fibrous (secondary). The fibres are rhomboidal or anvil shaped and can be more or less anisometric or isometric in cross section. When describing the shell microstructure, it is proposed to always mention both the width and the thickness of the fibres in the cross section and their range of variation for avoiding confusion arising from the literature. In some species the secondary layer is quite homogenous and monotonous, while in others it consists of several sheaves of fibres with different orientation. Special attention is paid to the myotest, which in some species appears as a thick distinct layer in a particular cross section. This study confirmes in general the validity of the classification of Kamyshan (1977), who distinguished two types of fibrous structure among the Mesozoic rhynchonellids - coarse-fibrous basiliolidine type and fine fibrous rhynchonellidine type. The studied Cretaceous genera have been accommodated in this scheme, although a large variation in fibre size is noticed in some species. An attempt is made to outline some diagnostic characters for each genus. Erymnaria and Orbirhynchia are characterized by basiliolidine type microstructure of the secondary layer, while Almerarhynchia, Belbekella, Burrirhynchia, Cretirhynchia, Cyclothyris, Grasirhynchia, Septatoechia - by rhynchonellidine type.

The benefits of using shell microstructure data in recognizing the taxa should not be overestimated. A complete pattern of the shell microstructure can be obtained only if a set of sections, both transverse and longitudinal, is made and examined. In this preliminary study two very close transverse sections in the mid-anterior part of the shell were observed for each specimen. Sometimes the dimensions of the fibres and the texture of the secondary layer have been found to vary widely from one section to the other in one specimen. Some diagenetic alterations of the shell, such as silicification and recrystallization are also discussed.

Petras MUSTEIKIS. Geology & Mineralogy Dept., Vilnius University, Ciurlionio 21/27 LT2009, Vilnius, Lithuania. (petras.mustekis@gf.vu.lt).

The spatial distribution of brachiopod communities in the Silurian of Lithuania shows its dependence on time (vertical distribution-evolution) and location in the basin (horizontal distribution-environment) reflecting the geological history of the basin. Evolution factor determines vertical disappearance of communities due to the evoutional extinction of brachiopod taxa. Much more complicated is environmental factor which determines lateral replacement of communities and their vertical replacement due to the environmental changes in time. It is suggested, that the main environmental factor in the distribution of communities is water depth. Lithuanian material shows, that in addition to water depth, restrictive factors including oxygen level, sedimentation rate, turbidity level, salinity, water transparance etc. were of great importance in the community distribution.

Thus in the Llandoverian, and during the first half of the Wenlockian, the Lissatrypa (BA 4-5, change in name from Glassia made necessary by Copper’s taxonomic work of 1996), Lissatrypa obovata-Skenidioides lewisii(BA 4-5), S.lewisii-Isorthis clivosa(BA 4), S. lewisii-I. amplificata(BA 3-4), Diceolosia-Skenidioides(BA 4), Diceolosia biloba-Ptychopleurella lamellosa(BA 4) and Atrypa reticularis (BA 3) communities were developed offshore to onshore, in eastern and central Lithuania. Offshore from Lissatrypa community pelagic communities (graptolites without shelly fauna, BA 5-6) were distributed.

In the second half of the Wenlockian, and into the Early Ludlovian, a shalower facies occurs because the basin regressed to the west. Lissatrypa, L. obovata —S. lewisii, S. lewisii-I. clivosa, S. lewisii-I. amplificata, Dicoelosia-Skenidioides and A. reticularis communities moved offshore westward. Shoreward from A. reticularis community Pentamerus(BA 3, late Wenlockian) or Kirkidium(BA 3, early Ludlovian) and Sphaerirhynchia wilsoni(BA 2-3, seaward of the small bioherms) communities occur.

In the Late Ludlovian to Early Pridolian the overall basin continued to undergo regression, and at this time terrigenous material input from the west increased significantly. Within this environment, in the same BA position Dayia(BA 4) and Dayia-Isorthis (BA 3-4) replaced the Lissatrypa, L. obovata —S. lewisii, S. lewisii-I. clivosa, S. lewisii-I. amplificata, Dicoelosia-Skenidioides communities. Onshore from these communities Isorthis ovalis(BA 3), I. ovalis-Microsphaeridiorhynchus nucula (BA 2-3), M. nucula (BA 2) and Atrypoidea(BA 2) communities occur. The disappearance of the Pentamerus and Kirkidium communities can be explained by taxic extinction in the Baltic basin.

In the Late Pridolian narrowing of the basin, and higher turbidity plus increased terrigenous material input were the reasons for bioherm disappearance in Lithuania, which caused extinction of Atrypoidea community inhabitated these bioherms, whereas the more tolerant M. nucula community continued. Basin regression eliminated the Dayia and Dayia-Isorthis communities to the west and southwest, leaving only the Isorthis ovalis, I. ovalis-Microsphaeridiorhynchus nucula and M. nucula communities.

B.S. NORFORD. Geological Survey of Canada, Calgary, Alberta, Canada.

The trimerellid brachiopods are an aberrant group of calcareous shelled brachiopods with a form of articulation distinct from the paired teeth and socket model that is basic to the articulate brachiopods. A medial plate within the dorsal valve fitted into a corresponding medial cardinal socket of the ventral valve. The stratigraphic range of the trimerellids has been documented as Middle Ordovian (late Llanvirn, Nemagraptus gracilis Zone to Late Silurian (Ludlow)) but some of the occurrences are not well dated. Many of the early studies on trimerellid brachiopods were based on internal moulds from Silurian carbonate rocks in the midcontinent of North America and in the island of Gotland. These provided considerable information on the internal platforms and muscle scars within the main bodies of the shells but little information concerning the exteriors or the posterior regions. More recent studies have included silicified specimens that have shown external features of the shells and have allowed detailed interpretations of the features of the hinge areas. Interpretations of the mode of articulation indicate that the amount of opening of the anterior margins of the shell was relatively small.

All known occurrences in Canada are reviewed and generic assignments are refined. New silicified matrial of several species allow more complete knowledge of the morphology of the cardinal regions, especially for species of Eodinobolus and Monomerella. In particular, the plate of the dorsal valve is a complex structure and very variable in size. The plate is very poorly shown by most internal moulds. Its upper surface terminates forward as a sharp edge that fits into the cardinal socket of the ventral valve. A smooth, generally gently convex upper surface nestles against the cardinal facet of the ventral valve and faces the pseudodeltidium. Its lower surface faces forward within the interior of the shell and bears a pair of almost transverse grooves that fade both medially and laterally. Some silicified specimens show the edge of the plate broken off and adhering to and obscuring the cardinal socket of the ventral valve; the remaining, amputated part of the plate commonly only shows the plate’s lower surface.

N. OLENEVA, Profsoyuznaja Str. 123, Moscow, Russia

Devonian brachiopods are widespread in the Altay structural-facial subzone and the Delyuno-Yutydsky flexure of the Mongolian Altay (Western Mongolia) were studied. All the three divisions of the Devonian are represented, but they differ lithologically and the faunal studies reveal the geological development of Western Mongolia.. From the moment of its origin until it closed up and was transformed into a folded structure, this territory was a part of a large Palaeozoic basin. There are 43 species of brachiopods in Mongolian Altay, representing 33 genera, 22 families and 7 orders. The taxonomic composition of faunas of the Altay subzone and the Delyuno-Yustydsky flexure are similar only at the level that corresponds to the Givetian stage. In the Altay subzone, Devonian sedimentation started in the Lochkovian. Breaks in the accumulation of sediments took place in the Pragian, at the beginning of the Emsian, and during the late Eifelian - early Givetian. The Altay subzone is characterized by wide development of Lower Devonian deposits; Upper Devonian deposits are also known.

Five brachiopod complexes are distinguished:1 (Lochkovian): Chalimochonetes huhunurensis, Hebetoechia vagranica mongolica, Howellella angustiplicata, H. laeviplicata. 2 (Emsian): Leptagonia orientalis, Leptostrophiella bayrimica, Wilsoniella prima, W. tchernyshevae. 3 (Eifelian): Protoleptostrophia explanata, Eucharitina dobrovi, Areella barunica, D. (Desquamatia) minussinensis. 4 (Givetian): Sibiratrypa lebedijanca, Leptagonia sinuata, Spinocyrtia martianofi, S. carinata, S. cedarensis, S. kizilschinus, S. mongolica, Euryspirifer pseudocheehiel, E. mesoloba, Athyris concentrica. 5 (? Frasnian, Famennian): Ksibiratrypa sp., Mucrospirifer mesacostalis, M. mesacostalis tricostatus, Retzia tschernyschewi, R. ulentica, Araksalosia sp. In the Delyuno-Yustydsky flexure, Devonian sedimentation was continuous from the Emsian to the Frasnian. Only Upper Frasnian deposits are absent. In contrast to the Altay subzone, Givetian and Frasnian deposits are well developed.

Five complexes of various ages are distinguished in the upper Emsian to Famennian in the Delyuno-Yustydnsky flexure. 1, (Emsian to Eifelian): Isorthis (Tyersella), Leptagonia orientalis, L. zlichovensis, Leptaenopyxis bouei, Leptostrophiella bayrimica; Protodouvillina matagarensis. 2 (Givetian): Isorthis (Tyersella) sibirica, Schizophoria striatula, Leptagonia sinuata, Tsaganella plana, Protodouvillina matagarensis, Sibiratrypa lebedijanica, Dagnachonetes dundensis, Spinocyrtia martianofi, Euryspirifer pseudocheehiel, E. pseudocheehiel alatus, Athyris concentrica. 3 (Givetian to Frasnian): Carinifirella ulitinae, Schizophoria sp., Leptagonia vladimiri, Caucasiproductus dissimilis, Sibiratrypa vassinensis, Cyrtospirifer schelonicus, Euryspirifer pseudocheehiel, Mucrospirifer mesacostalis, M. mesacostalis tricostatus, Retzia tschernyschewi, R. amoena, Athyris concentrica.

4 (Frasnian): Douvillinoides singularis, Eoschuchertella chemungensis, Cyrtospirifer schelonicus, C. verneuili echinosus, Eleutherokomma rhykensis, Elytha fimbriata. 5 (Famennian): Cyrtospirifer tschernyschewi, C. procumbens.

D. G. OSTROW^1,2, S. R. WING¹, M. S. ROY², and P. V. MLADENOV¹

1Department of Marine Science, ²Department of Zoology^, Otago University, Dunedin, New Zealand.

The lack of known effective physical barriers in the marine environment has led to the perception that marine organisms have high dispersal capabilities and correspondingly low inter-population genetic differences. Due to the hydrography of the 14 deep-water fiords on the western coast of New Zealand’s South Island, inhabitants of Fiordland’s marine environment may be limited in their dispersal. Among the unique assemblage of organisms inhabiting the fiords are four species of articulate brachiopods. The most common of these, Terebratella sanguinea, occurs in 12 of the fiords. Larvae of these animals are believed to have a 1-2 day planktonic stage during which dispersal occurs. Dispersal into or out of the fiords may be limited, however, by the weak gravitational estuarine circulation that may prevent passive transport of larvae out of natal areas. In order to test whether genetic differentiation between fiord populations is occurring, we used allozyme electrophoresis to determine the genetic structure of T. sanguinea populations in Fiordland. Six presumptive gene loci coding for 5 enzymes were used. Preliminary data from the northernmost and southernmost fiords inhabited by T.sanguinea indicate that certain "unique" alleles may be present in different fiords. These results are consistent with our hypothesis that fiordic brachiopod populations have differentiated due to an interruption of gene flow.

Miguel V. PARDO ALONSO. Departamento. Geología, Universitat de València, C/ Dr. Moliner, 50. E-46100 Burjassot (Valencia), Spain. (miguel.v.pardo@uv.es)

The presence of some fossils of terebratulids has been cited by Pardo and García-Alcalde (1984) in the Devonian of the southern part of the Central-Iberian Zone. Some of them were named as Globithyris ? sp. in the same paper. New specimens and accurate research have revealed that these examples belong to three new species; this cluster also belongs to a new genus.

At first sight, this group resembles some species of Globithyris. The general shape, external attributes and internal morphology of the ventral valve are similar to this genus. Despite this similarity, the new species show a cardinalium morphology distinguished by the lack of crural plates or septalium, structures that are common among the species of Globithyris.

Certainly the systematic position of the new genus is very close to Globithyris, because of the great resemblance between the two of them; because of that, the new genus ought to be placed in the subfamily Globithyridinae Cloud, 1942. The diagnosis of this subfamily must be emended, in order to include those species with no crural plates or septalium.

The new species are more or less common in the Pragian-Lower Emsian (Lower Devonian) of the Herrera del Duque syncline, and scarce in the Pragian of the Almadén syncline; they have not been found in the rest of the southern part of the Central-Iberian Zone, where the Lower Devonian fossils are very rare. In spite of that, these species can be a good tool for a local biostratigraphy, because they appear in a sequence and do not coincide in the same strata.

This work was supported by the project of "Dirección General de Enseñanza Superior" (Spanish Ministry of Education) PB98/1542 and it is a contribution to the project IGCP 421 "North Gondwana Mid-Palaeozoic Bioevent/Biogeography patterns in relation to crustal dynamics".

Miguel V. PARDO ALONSO¹ and Christian C. EMIG². ¹Department de Geologia, Universitat de València, E-46100 Burjassot Spain.(miguel.V.Pardo@uv.e). ²Centre d'Océanologie, F-13007 Marseille France.

(Christian.Emig@com.univ-mrs.fr).

The present EuroBrachNet (http://www.com.univ-mrs.fr/EuroBrachNet) and World Brach Net (http://www.com.univ-mrs.fr/EuroBrachNet/WBN.htm) home pages, physically located in Marseilles, have as main aim to provide to the brachiopodologist community the following topics: - Bibliography since 1995; - Directory of all the brachiopodologists (and in Europe their geographic location), but all specialists are not listed; - Systematics and taxonomy of the Brachiopoda; - Announcements; - Links to other lophophorate web pages. The EBN & WBN pages are updated as new information reaches the webmaster (presently Christian Emig), mainly that sent in by the brachiopodologists to feed the home pages.

The development of those Web sites is under study to increase relationships within the brachiopodologist community. For that, several services may be proposed through RedIRIS, the Spanish Academic and Research Network (http://www.rediris.es). The basic tools will be a list server which is a simple and fast way to interchange any information, as well as the BSCW (Basic Support for Co-operative Work) and web-based file management software.

On the other hand, based on co-operation with all brachiopodologists, we suggest offering:-

- A multilingual dictionary of morphological and anatomical terms in Brachiopoda, available on WBN site, to facilitate translation of the usual "technical" words in, at least, the following languages: French, Spanish, German, Italian, and Portuguese, the English terms will be based on the glossary, published in the vol. 1 of the Treatise on Invertebrate Paleontology, Part H (1997). Collaboration with colleagues speaking these languages is highly desirable.

- Several web pages popularising "what is a brachiopod" and our research as brachiopodologist, for students, general public, and palaeontologist amateurs.

- Setting-up a database about brachiopod systematics and taxonomy. This project should develop the task done previously by Rex Doescher. The database will be located in RedIRIS, including images and other multimedia materials. It is emphasised that such a database may be complementary to the Treatise, and continuously updated!

The World Brach Net should become the "official" structure of our scientific community working on or dealing with Brachiopoda linking all the members and acting as its window. The development of the net depends directly upon the need expression and the use of the web pages made and fed by our scientific community. Feel free to contact by email the authors of this abstract.

L.S. PECK, K. MEIDLINGER¹ and P.A. TYLER¹. British Antarctic Survey, High Cross, Madingley Road, Cambridge, CB3 0ET, UK. ¹Southampton Oceanography Centre, Waterfront Campus, European Way, Southampton, SO14 3ZH, UK.

Larvae of the Antarctic brachiopod Liothyrella uva (Broderip 1833) were cultured from the gastrula stage at 18 days post-fertilisation to settlement at 65 days post-fertilisation. L. uva broods its larvae and releases them over a wide range of developmental stages from early gastrula to larvae competent to settle. Developmental times were obtained from the time taken for larvae released at early developmental stages to reach later developmental stages. On settlement mantle reversal was observed, and 4 bundles of mantle setae observed. This was prior to any evidence of calcification of the shell. Laboratory trials showed more larvae settling on conspecific shells than other available substrata (rock, tile, glass or plastic). Some larvae took many days to settle, whereas on a few occasions settlement was observed within minutes of release, and in these cases larvae settled mainly around the outer edges of the parental shell. Settlement numbers were too few to assess any effects of rugosity or shell shape. Field trials found more larval settlement on live conspecifics than dead shells. Field trials also found larval settlement occurring in the mid to late austral summer. L. uva is a species which, in caves and large crevices, occurs in a continuous pavement several layers thick, at densities over 500 m^-2, being reminiscent of brachiopod assemblages from previous epochs. These settlement characteristics would facilitate the production of such assemblages.

Alberto PÉREZ-HUERTA. Departamento de Geología, Universidad de Oviedo, Oviedo, Spain.

In spite of their potential for biostratigraphic correlation of Cambrian sequences in the Cantabrian Zone, brachiopods were commonly ignored in favour of trilobites and archaeocyathans. However, preliminary survey of the Zone has proved that brachiopods are reasonably diverse and abundant and show promise for at least regional correlation within the platform environments. Careful re-investigation of old collections and study of new specimens recollected in classical localities showed that about seven species and a few assemblages could be recognized. The publication of Volumes 2 and 3 of the Revised Edition of the Treatise on Invertebrate Paleontology, Part H (Brachiopoda), with the description and distribution of most Cambrian taxa, will greatly help the systematic and phylogenetic study of these brachiopods. The preliminary results, presented here in much abbreviated form, were obtained in the frame of a wider project. The main objective of this project is to document all ‘articulate’ and ‘inarticulate’ Cambrian brachiopods from the Cantabrian Zone (North of Spain), to discuss their morphology, systematic position and phylogenetic relationships, and make preliminary comments on their biostratigraphic and paleobiogeographic significance.