Annales de Paleontologie最新文献

The study of the coral biodiversity of the Upper Oligocene sedimentary series (Lower Coralline Limestone, Chattian) of Malta permitted the identification of 25 scleractinian genera represented by 41 species. Three new species are proposed: Miophora naxxarensis n. sp., Nerthastraea maltensis n. sp. and Gyrosmilia maltensis n. sp. Observations made in various Oligocene sites in Malta, especially around Naxxar and Tal Bajjada, allow to establish a suite of coral associations which may vary spatially and vertically. The identified scleractinian associations can be represented by different types of coral assemblages and bioconstructions: isolated colonies, coral beds of varying density but of large spatial extent, more cohesive coral banks (coral carpets) or patch reefs forming morphologies with gentle lateral slopes. The colonial morphologies are closely linked to these different types of bioconstructions. These coral constructions have been established and developed in shallow marine areas. The coral biodiversity of the Oligocene of Malta fits well in the evolution of the Cenozoic reef phenomenon whose development reached its peak in the Oligocene with great coral richness in the Chattian in the Mediterranean area.

Due to an impact of a bolide at the K/Pg boundary, the planktonic foraminifera have suffered sever mass extinction. However, no small Benthic Foraminifera species have documented mass extinction at the K/Pg boundary. Nevertheless, many species showed disturbance. The Maastrichtian assemblages may be different from those of the lower Paleogene by their species content, diversity and frequencies. At Oued Es Smara and Oued Abiod sections, the small benthic foraminifera indicate lower bathyal environment, and manifest significant faunal turnover. Until the uppermost Maastrichtian, their assemblages are highly diversified, with 77 species and 76 species respectively at Oued Es Smara and Oued Abiod sections. These are dominated by endobenthic morphotypes. At the K/Pg boundary, although 33 species (42,85%) (Oued Es Smara section) and 27 species (35,52%) (Oued Abiod section) of them seem to disappear, but only few species have really extinct such as Arenobulimina obesa. Nevertheless, the majority of species persist elsewhere at the Danian (e.g., Pseudoglandulina manifesta, Cibicioides proprius, Clavulinoides amorpha, Coryphostoma plaitum, Pullenia coryelli). At the lower Danian, the survivor Maastrichtian species are of 58% (Oued Es Smara) and 65% (Oued Abiod). Throughout the Parasubbotina pseudobulloides subzone, 4 others species were progressively disappeared. They are oligotrophic and low oxygen tolerant. About the Masstrichtian species, at the two studied sections (e.g. Gaudryina inflata and Tritaxia midwayensis) they seem to be more trophic exigent. Consequently, the benthic Foraminifera did not suffer massive extinction at the K/Pg boundary, but their assemblages underwent a significant faunal turnover which reflects important environmental changes. These changes are compatible with the catastrophic scenario induced by the large asteroid impact.

During the Triassic in Europe, the Germanic Basin extended from England in the west to the eastern border of Poland in the east. Although cephalopods are common in some Middle Triassic (Muschelkalk) horizons, there still persists a gap in the palaeontological record of the eastern part of the Germanic Basin, notably in the lowermost parts of the Lower Muschelkalk, spanning the latest Olenekian-Aegean interval. The present contribution attempts to fill this gap by presenting the first ammonoid (ceratitid Beneckeia sp.) and nautiloids (Germanonautilus cf. dolomiticus and G. cf. salinarius) from the Lower Gogolin Beds (Upper Silesia, Poland). These Germanonautilus are the oldest nautiloids found in the entire Germanic Basin.

This article focuses on some new material of currently called Miotragocerus/Tragoportax complex of species, collected from Nagri type locality, early Late Miocene (10.039 to 9.969 Ma) of the Siwalik Group of Pakistan. Along with the material description, the issues regarding the taxonomic status of Tragoportax, Miotragocerus, Sivaceros and Helicoportax are briefly discussed on the basis of preliminary results of ongoing thorough research on the Siwalik bovids. Furthermore, the priority of Graecoryx over Miotragocerus, the synonymy of Sivaceros with Graecoryx, the distinction between Tragoportax and Graecoryx, and some hypotheses have been laid down for future work, based on the morphological study.

While Late Cretaceous ophiuroids are relatively well known in Europe, these faunas have been much less studied in North Africa. With the exception of some Tunisian assemblages preliminary described at the turn of the 21st century, nothing is known about the Cretaceous brittle stars of the southwestern Tethyan margin. The present paper seeks to bring the first data about hitherto unknown ophiuroids recently found in the early upper Cenomanian succession of the eastern side of the Preafrican trough (Menaguir section, Algeria). This “community” of brittle stars comprises at least eight species. Most of them are probably new, but have not been formally named here. These are representatives of the families Hemieuryalidae, Amphiuridae, Ophiodermatidae, Ophiacanthidae, Ophiopezidae and probably also Ophiomyxidae and Ophiobyrsidae. Almost all vertebrae are zygospondylous; no streptospondylous vertebrae indicate the absence of the order Euryalida here. Most of the ophiuroids belong to the orders Amphilepidida and Ophiacanthida. Ophiotitanos serrata, Ophiomyxa? aff. jekerica, Ophiojagtus? sp. and some other taxa resembling ophiuroid assemblages from the Late Cretaceous of central, western and northern Europe. With respect to the late Cenomanian age, the depth of the sea and the taxonomic composition, there are some similarities with ophiuroids of the Bohemian Cretaceous Basin. The mid-ramp subtidal facies suggests that brittle stars lived here in a warm, euphotic and probably shallow sea.

Abundant, though moderately well-preserved, specimens of Pagetia sp. are recorded along with the ptychopariid Xingrenaspis dardapurensis from a new stratigraphic level which lies above the Oryctocephalus salteri biozone in the Spiti region (Himalaya). This occurrence of Pagetia in a higher stratigraphic level (higher than the Oryctocephalus salteri biozone) from the Spiti region helps in understanding the distribution of this taxon in the Cambrian of the Kashmir and Spiti regions of the Himalaya. A Pagetia-Xingrenaspis association from the Kashmir region is already known, the present discovery of a similar association in the Spiti region enables the Wuliuan (Miaolingian) biostratigraphic correlation between the Kashmir and the Spiti regions. The record of the taxon Pagetia from a higher stratigraphic level in the Spiti region contradicts the previous assumption that the Pagetia bearing level in Kashmir is equivalent to the Pagetia-Oryctocephalus indicus (O. indicus biozone, Hayden horizon 2) in the lowest part of the Wuliuan in the Spiti region.

The first plant microfossil assemblage from the Si Ka Formation of the Song Cau Group, northern Vietnam is reported. It is composed of cryptospores in dyads and tetrads, trilete spores, tubular remains consisting of an association of smooth, banded, and externally thickened tubes, and cuticle-like fragments. The biostratigraphic assemblage of sporomorphs indicates a late Silurian (late Ludfordian) to Early Devonian (early Lochkovian) age. Further comparison with coeval reports using the characteristic features of the assemblage confines their age to the late Ludlow (late Ludfordian) to early Přídolí. This report presents the oldest spore assemblage from Vietnam and contributes to a broader understanding of its paleo-landscape during the late Silurian.

The Rectogordius (Foraminifera) abundance zone is described in the east of the Shishtu village in the Ozbak Kuh Mountain. The samples were collected in the Zaladou Formation., which is 60 m thick and composed of shales, sandstones, sandy limestones, microconglomerate, bioclastic limestones, coral limestone and fusulinid limestones. The Rectogordius abundance zone was found in sandy bioclastic limestone. It displays two species and three subspecies of this foraminifer, including Rectogordius iranicus, R. iranicus gadukensis, R. minimus and R. minimus shishtuensis n. subsp., R. iranicus ozbakensis n. subsp. The age of this abundance zone is considered to be Gzhelian, due to the distribution of Rectogordius in Central Iran (Ozbak Kuh; Zaladou Formation), central and eastern Alborz (Emarat Fm.), Sanandaj-Sirjan zone (Vazhnan Formation), as well as in the Donets, Arctic Canada, Afghanistan, and the Carnic Alps. The genus Rectogordius is possibly restricted to the northern Paleotethys margin, northern Cimmerian margin, shelf of the Uralian Ocean as far as the northernmost part of North America. Two new subspecies Rectogordius minimus shishtuensis n. subsp. and Rectogordius iranicus ozbakensis n. subsp. are described.