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2006 (vol. 6)  

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.

Online since December 14, 2006


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
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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.

Online since September 21, 2006


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.

Online since September 19, 2006


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.

Online since September 8, 2006


Fig. 83 revisited

Online since August 2, 2007


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
Lang.: 

 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.

 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.

Online since May 11, 2006


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
Lang.: 

 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.

Online since May 11, 2006


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.

Online since March 15, 2006


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
Lang.: 

 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.

Online since February 14, 2006


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
Lang.:  

 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.

Online since January 30, 2006


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