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2006 (vol. 6)
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Article 5 [2006]: New micropalaeontological studies on the stratotype of the Campanian-Maastrichtian boundary at Tercis (SW France): the gilianelles (microproblematica) extracted through acetolysis, by Gilles Serge ODIN & Alexandre LETHIERS.- Format [HTML] or [PDF
4,212 KB] Reference: [CG2006_A05]
DOI:
10.4267/2042/6697
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Abstract: The Campanian-Maastrichtian stratotype section at Tercis (SW France)
consists mainly of hard calcareous levels. Their treatment using acetolysis
left residues among which for the first time well-preserved free microfossils were obtained
(These levels had been studied previously only through thin sections). Within these residues, a wealth of calcareous shells of unknown affinity (incertae sedis) occur. These
previously undescribed fossils are documented herein with photographs and drawings. Optical observations are synthesised in computer assisted drawings which depict 36
discrete forms. Scanning electron microscopy documented the nannostructures of these tests which
led to the recognition of 30 forms with a common organisation and
nannostructure. These are the microproblematica group called "gilianelles". The remaining six forms of incertae sedis do not
share the same characteristics. According to morphological observations, a planktonic
existence is inferred for most of the incertae sedis. The simple organisation and small size of the gilianelles suggest that they may represent a new Order of Rhizopod
Protozoans. Their stratigraphical distribution has been established in the stratotype section
of the "Grande Carrière" at Tercis (SW France). This distribution
shows an extraordinary rate of turn-over with some taxa having a range of less than 1 Ma.
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Online since December 14, 2006
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Article 4 [2006]: Schmidtites celatus (Obolida, Brachiopoda) from the "Obolus sands" (Upper Cambrian - Lower Ordovician) of Estonia, by Christian C. EMIG.- Format [HTML] or [PDF 801 KB] Reference: [CG2006_A04]
DOI:
10.4267/2042/5837
Lang.:
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Abstract: Large collections of the brachiopod obolid Schmidtites celatus have been gathered from Upper Cambrian-Lower Ordovician strata in four northern Estonian localities. The morphological features and the taxonomic characters of the genus and of the single species representing it are
re-described and illustrated. New diagnoses are proposed based on characters of the shell and morphological traits that permit Schmidtites celatus to be compared with and distinguished from the other obolid genera occurring in the same samples or areas,
i.e. Ungula ingrica, Oepikites, and Obolus apollinis which now includes specimens formerly described as Ungula convexa. Schmidtites celatus differs from them mainly in the arrangement of its musculature.
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Online since September 21, 2006
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Article 3 [2006]: Are the green algae (phylum Viridiplantae) two billion years old?, by Bernard TEYSSÈDRE.- Format [HTML] or [PDF 303 KB] Reference: [CG2006_A03]
DOI:
10.4267/2042/5836
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Abstract: In his book, Life on a young planet,
A.H. Knoll states that the first documented fossils of green algae date back 750 Ma. However, according to B. Teyssèdre's
book, La vie invisible, they are much older.
Using a method which combines paleontology and molecular phylogeny, this paper is an inquiry into the Precambrian fossils of some "acritarchs" and of a
primitive clade of green algae, the Pyramimonadales. A paraphyletic group of unicellular green algae, named "Prasinophyceae", is represented at Thule (Greenland) ca. 1200 Ma by several morphotypes of the
monophyletic Pyramimonadales, including Tasmanites and Pterospermella
that are akin to algae still living today. These two, and others, probably had forerunners going back 1450 / 1550 Ma. Some acritarchs that may
represent Pyramimonadales producing "phycomas" which split open for dehiscence were
confusingly included in the polyphyletic pseudo-taxon "Leiosphaeridia" and are possibly already present at Chuanlinggou, China, ca. 1730 Ma. Many
acritarchs that Timofeev obtained by acid maceration of Russian samples dated between 1800 and 2000 Ma were probably unicellular Chlorophyta which
synthesized algaenans or other biopolymers resistant to acetolysis. Living Prasinophyceae are undoubtedly green algae (Viridiplantae). Thus, if Prasinophyceae fossils go back
certainly to 1200 Ma, probably to 1500 Ma and possibly to 1730 Ma, then the ancestor of green algae (Chlorophyta and Streptophyta) probably separated from the ancestor of red algae (Rhodophyta) as early as 2000 Ma.
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Online since September 19, 2006
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Memoir 2 [2006]: Illustrated glossary of terms used in foraminiferal research, by Lukas HOTTINGER.- Format [HTML]
or [ PDF
Text 739 KB + PDF
Figs. 2-27 8,827 KB + PDF
Figs. 28-46 7,391 KB + PDF
Figs. 47-68 6,805 KB + PDF
Figs. 69-83 6,454 KB] Reference: [CG2006_M02]
DOI:
10.4267/2042/5832
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Summary: An illustrated
glossary of terms used in the analysis of the shells of recent and fossil
foraminifera supplemented by a rigorous selection of terms that facilitate an
understanding of their biology and their use in ecology and biostratigraphy. The
glossary includes some 650 entries illustrated by 83 - often composite –
figures many of which are stereographs or 3D models. A taxonomic index lists the
140 taxa illustrated.
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Online since September 8, 2006
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Fig. 83 revisited
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Online since August 2, 2007
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Memoir 1 [2006]: The Deshayesitidae STOYANOV, 1949 (Ammonoidea) of the Aptian historical stratotype region at Cassis-La Bédoule (SE France), by Pierre ROPOLO, Michel MOULLADE, Roland GONNET, Gabriel CONTE & Guy TRONCHETTI.- Format [HTML] or [PDF 15,159 KB] Reference: [CG2006_M01]
DOI:
10.4267/2042/4744
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Abstract:
One of the significant results of the multidisciplinary investigations carried out during recent years in the Lower Aptian historical stratotype of the Cassis-La Bédoule region (South-Eastern France) was a proposal to update the local Upper Barremian/Lower Aptian ammonite biozonation in order to be more consistent with the standard Mediterranean zonal subdivisions. So the lower and upper boundaries of the Lower Aptian (= Bedoulian substage of most French authors) as well as the boundaries of four biozones (Paradeshayesites tuarkyricus, P. weissi, Deshayesites deshayesi, Dufrenoyia furcata
zones) and two subzones (Roloboceras hambrovi and Paradeshayesites grandis
subzones) were identified and formally defined in the stratotype. However, to support this zonal
scheme additional descriptions and illustrations of the ammonites collected bed by bed in the several sections studied were still required. In this paper we describe the members of the most significant ammonite family found in the Lower Aptian of Cassis-La Bédoule, i.e. the Deshayesitidae, and delimit precisely their stratigraphic positions. As regards zonation, we have replaced the index ammonite of the earliest Bedoulian Zone, i.e. Paradeshayesites tuarkyricus (BOGDANOVA,
1983), by Paradeshayesites oglanlensis (BOGDANOVA, 1983), and re-established the Pseudocrioceras waagenoides Zone as a subzone.
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Corrigendum: There is an error in the labeling of Plate 8 in the above Memoir.
Consequently, the above plate caption:
Fig. 2.- Deshayesites evolvens LUPPOV, 1952 (Abm311), Les Fourniers
section, bed 115. P. weissi Zone.
Fig. 3.- Deshayesites sp. gr. spathi/normani CASEY, 1964
(ABR340), Les Fourniers section, bed 111. P. weissi Zone.
Should read as follows:
Fig. 2.- Deshayesites sp. gr. spathi/normani CASEY, 1964 (ABR340), Les Fourniers
section, bed 111. P. weissi Zone.
Fig. 3.- Deshayesites evolvens LUPPOV, 1952 (Abm311), Les Fourniers section, bed
115. P. weissi Zone.
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Online since May 11, 2006
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Letter 2 [2006]: Ankylosaurid (Dinosauria: Thyreophora) osteoderms from the Upper Cretaceous Cerro del Pueblo Formation of Coahuila, Mexico, by Héctor E. RIVERA-SYLVA & Belinda ESPINOSA-CHÁVEZ.- Format [HTML] or [PDF 617 KB] Reference: [CG2006_L02]
DOI:
10.4267/2042/4741
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Abstract: Ankylosaurian dinosaur osteoderms have been discovered in the southeastern part of the State of Coahuila, Mexico, in the township of General Cepeda, in the locality known as El Palmar. The osteoderms were collected from rocks that had been correlated to the Cerro del Pueblo Formation (Late Cretaceous: Campanian) of the Difunta Group. The fossil material includes four dermal scutes and three associated fragments that at present cannot be identified. This is the first description of ostoederms and ankylosaurian material from Coahuila.
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Online since May 11, 2006
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Article 2 [2006]: Decastronema kotori gen. nov., comb. nov.: a mat-forming cyanobacterium on Cretaceous carbonate platforms and its modern counterparts, by Stjepko GOLUBIC, Rajka RADOIČIĆ & Lee SEONG-JOO.- Format [HTML] or [PDF 1,061 KB] Reference: [CG2006_A02]
DOI:
10.4267/2042/4674
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Abstract: The fossil renamed here was first
described in 1959 as Aeolisaccus
kotori Radoičić, a new species of a
problematic fossil worm, Aeolisaccus
Elliott. In 1975 De Castro
recognized the true relationships of this microbial fossil: a cyanobacterium
related closely to the modern genus Scytonema. The fossil is common in
the sediments of the Mesozoic carbonate platforms of southern Europe. This
contribution confirmed De Castro's interpretation,
determined, using the high resolution of the SEM, the extent to which these
fossils have preserved their original architecture, and investigated their
presumed modern counterparts among the abundant mat-forming species of Scytonema
on the intertidal flats of Andros Island, a part of the Bahama carbonate
platform. The systematic affinities of the fossil and the environments it
inhabited were reconstructed by comparing the morphology of the fossils to that
of their modern counterparts, along with their respective sedimentary contexts.
Based on these comparisons, we conclude that the organism lived in a peritidal
environment and was buried and fossilized in the shallow waters of an ancient
carbonate platform. A formal transfer of the fossil to a new genus of fossil
cyanobacteria thereby designated as Decastronema gen. nov. is proposed,
honoring the contribution of Prof. Piero De Castro
to paleontology.
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Online since March 15, 2006
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Article 1 [2006]: Microbiofacies analysis of Cambrian offshore carbonates from Sardinia (Italy): environment reconstruction and development of a drowning carbonate platform, by Olaf ELICKI.- Format [HTML] or [PDF 1,558 KB] or [PDF 1,592 KB - A3-sized pages 10-11] Reference: [CG2006_A01]
DOI:
10.4267/2042/4567
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Abstract:
The Campo Pisano Formation of southwestern Sardinia is represented by an
offshore carbonate succession spanning the latest Early to late Middle Cambrian.
Paleogeographically, the fauna is characteristic of western Perigondwana, and
indicates faunal relations to France, Spain, and Turkey. Microfaunal
paleoecology reflects drowning of an isolated carbonate platform at tropical
latitudes. Sessile epibenthic filter feeders dominate at the base, succeeded
upward by sessile, epibenthic, suspension feeders. Upsection, a shift in the
ratio of faunal groups indicates increasing replacement by mobile epibenthos.
Autochthonous faunal elements decline near the top where allochthonous taxa
become important. In the basal portion of the formation the faunal succession
indicates relatively shallow neritic habitats with a moderate influx of
suspended sediment, followed by a period of slightly deeper neritic conditions.
Probably a shallow bathyal environment was established at the transition to the
overlying siliciclastic Cabitza Formation. The bathymetric and ecofacies changes
in the Campo Pisano Formation are interpreted as having been caused by a
discontinuous rise in eustatic sea-level, probably accompanied by subsidence due
to tensional tectonics. The depositional environment was that of a distal
open-marine shelf or ramp without strong relief. This interpretation is
supported by the lack of significant lateral changes in the fossil assemblages,
and an upward deepening of facies. The applied micropaleoecological approach is
proven a powerful tool in regional stratigraphy and in the reconstruction of
sedimentary realms in the Mediterranean Cambrian, particularly when
high-resolution biostratigraphic data and diagnostic sedimentary characteristics
are sparse.
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Online since February 14, 2006
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Letter 1 [2006]: The Gargasian (Middle Aptian) of La Tuilière - St-Saturnin-lès-Apt (area of the Aptian historical stratotype, Vaucluse, SE France): geographic setting and outcrop correlation, by Michel MOULLADE, Guy TRONCHETTI, Christine BALME & Georges KOUYOUMONTZAKIS.- Format [HTML] or [PDF 553 KB] Reference: [CG2006_L01]
DOI:
10.4267/2042/4564
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Abstract: A stratonomic and micropaleontological analysis of the Aptian marls cropping out in the La Tuilière area near
Saint-Saturnin-lès-Apt (Vaucluse, SE France), enabled us to reconstitute a continuous succession almost 120 m thick, that includes the upper terms of the Lower Aptian
(Bedoulian) and the lower part of the Middle Aptian (Gargasian). These levels had never before been observed with such continuity in the Gargas region, the Aptian historical
stratotype.
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Online since January 30, 2006
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