Annales de Paleontologie最新文献

The Ouarsenis Massif belongs to the Algerian Tell domain, which is considered as the eastern part of the Maghrebian Tethys former margin. The Berriasian-Valanginian Oued Fodda Formation outcropping in the Kef Aïn El Hadjela section, at the foot of the great peak of the Ouarsenis Massif, is composed of marls and laminated and bioturbated limestone alternations. The marl facies reveals diverse microfauna, including crinoids. These latter are represented by: Isocrinida [isocrinids Balanocrinus cf. gillieroni (de Loriol), Percevalicrinus aldingeri Klikushin, Isocrinus? lissajouxi (de Loriol)], Cyrtocrinida [cyrtocrinids (Phyllocrinus sp., Hemibrachiocrinus sp.)], and Roveacrinida gen. indet. sp. indet. [roveacrinids]. All these, with exception of roveacrinids and phyllocrinids, are noted for the first time from Algeria and African continent (southern margin of Tethys in the Maghreb). Knowledge on Cretaceous crinoids formerly described from Algeria is presented. It is also shown that crinoid assemblage and associated invertebrates are typical for relatively shallow, distal depositional setting situated below storm wave base.

Apart from the few works carried out in the North Tethyan basins, the palynological study of Mesozoic outcrops is still rare. Thus, the present study devoted to the Zahra Marls Formation (upper Bajocian) of the Rhar Roubane Mountains (northwestern Algeria), allowed us for the first time to inventory 44 different taxa. The palynological assemblages studied are strongly dominated by trilete spores (17 genera and 26 species), the most abundant of which are Concavissimisporites variverrucatus, Cyathidites australis and Cyathidites minor. Pollen grains are relatively frequent (10 genera and 16 species), while acritarchs and algae are represented by only two taxa (Micrhystridium sp. and Botryococcus sp.). In addition, the sporopollinic spectra dominated by the terrestrial elements are represented mainly by the spores of Pteridophyta and Bryophyta and gymnosperm pollen.

Ediacaran-Cambrian bioturbation on bedding planes provides physical and chemical data about the environmental conditions and biological activities of early metazoans. We propose a quantitative method to estimate horizontal disruption of the substrate using bedding-plane trace fossils from Brioverian deposits. This methodology provides the first quantitative analysis of the trace fossil assemblage from the Armorican Massif (Brittany, NW of France). The Ediacaran-Cambrian transition within the Brioverian series is characterized by the abundance of simple and horizontal trace fossils such as Helminthopsis, Helminthoidichnites, and Palaeophycus as well as rare Gordia and Spirodesmos. Recent U-Pb dating has been carried out on detrital zircon grains from the upper Brioverian series suggesting a late Ediacaran to Fortunian age of the fossiliferous deposits (ca. 550 to 530 Ma). With Arc-Gis software, we use a semi-quantitative approach to estimate the relative 2D bioturbation rate recorded on bedding planes. The dataset is used to discuss the feeding strategies and how the seafloor ecospace was colonized by the early bilaterian metazoans. This approach combines new values such as: the length of a trace fossil, the surface of a trace, the cumulative length, and the cumulative surfaces from all of the ichnofossils recorded on the same slate surface, to finally suggest that the bioturbation rate of the microbial grazers impacted the use of the seafloor ecospaces and feeding strategies through the biomats.

In the central High Atlas, the Toarcian Stage is represented by a marl and marly limestone series of variable thickness. Two sections have been studied: Amellago (500 m) and Aït Athmane (100 m). Ammonites from the two sections allowed to characterize the Polymorphum, Levisoni, Bifrons, Gradata, and Speciosum zones. The Polymorphum Zone provided, among others: Dactylioceras (Eodactylites) mirabile, D. (E.) pseudocommune, Dactylioceras (Orthodactylites) aff. crosbeyi and Neolioceratoides aff. hoffmanni; the Levisoni Zone provided a rich ammonite fauna composed of, Calliphylloceras nilssoni, Dactylioceras (Orthodactylites) cf. semiannulatum, Eleganticeras exaratum, Harpoceras falciferum, H. pseudoserpentinum, H. serpentinum, H. subplanatum, Hildaites cf. forte, H. levisoni, H. cf. serpentiniformis, H. cf. subserpentinus, H. striatus, H. wrighti, Lytoceras siemensi, Lytoceras sp., Maconiceras soloniacense, Phylloceras sp., Polyplectus pluricostatum et Polyplectus sp.; the Bifrons Zone provided Eleganticeras sp., Harpoceras subplanatum?, Hildoceras bifrons, H. lusitanicum, H. semipolitum, H. sublevisoni, Hildoceras sp., Porpoceras gr. vortex – verticosum; the Gradata Zone was characterized by Pseudocrassiceras bayani, P. frantzi, Pseudocrassiceras sp., Pseudocrassiceras sp. indet.; and the Speciosum Zone provided an Hammatoceras aff. insigne. These species have been described and illustrated for the first time for the central High Atlas. Most of them are common to several basins of the north Tethyan margin and the Subboreal Domain of NW Europe.

The genus Subpterynotus Olsson and Harbison, 1953 was until very recently a composite genus in which several species, now attributed to Eofavartia Merle, 2002 and Exquisitor Merle, Garrigues and Pointier, 2022, were included. Its revision clarified its distribution in the geological record and the description of two new species, S. eocaenicus nov. sp. from the Bartonian of the Paris Basin and S. mainotensis nov. sp. from the Aquitanian of the Aquitaine Basin, increases our knowledge on the palaeobiogeography of the genus. Subpterynotus eocaenicus nov. sp. extends the First Appearance Datum (FAD) of the genus in the middle Eocene (early Bartonian) of Europe, whereas before it was known only in the upper Eocene (Priabonian). Subpterynotus mainotensis demonstrates the persistence of the genus in the Miocene (Aquitanian) of Europe. As no Subpterynotus is known on tropical western Atlantic coast of America prior to the Burdigalian (Chipola Formation, Florida, USA), its presence suggests an east-west dispersal. The palaeobiogeographic scenario of Subpterynotus is compared to those of Eofavartia Merle, 2002 and Exquisitor Merle, Garrigues and Pointier, 2022, which are also thermophilic taxa. It differs from that of Eofavartia which has a west-east dispersion towards Indo-Pacific and that of Exquisitor whose area is restricted to the Miocene European-West African (tropical) Province for the extinct species and to the south of the Mediterranean-Moroccan Province for the extant Atlantic species.

Since its first description in 1960, the brachyuran crab genus Pleolobites was restricted to the Eocene (Ypresian) strata of Ivory Coast. Here, we report newly collected specimens that indicate its presence in the Paleocene (Thanetian) of Togo. This monotypic genus has been classified within various higher taxa, including Portunidae, Macropipidae, and Carcinidae, depending on the concurrent classification of portunoid crabs. Through the re-examination of the type material of Pleolobites erinaceus, the most recent assignment of Pleolobites within the subfamily Polybiinae of the family Carcinidae is disputed herein. Nevertheless, we refrain from assigning Pleolobites to any family and opine for its placement as Portunoidea incertae sedis. Additionally, the crab genus Rhachiosoma, morphologically similar to Pleolobites, is also removed from Polybiinae and placed in Portunoidea incertae sedis. It is further argued that Palaeoxanthopsis, Paraverrucoides, Parazanthopsis, and Verrucoides currently classified within the family Palaeoxanthopsidae of the superfamily Carpilioidea show striking similarities with Pleolobites and Rhachiosoma, including the morphology of dorsal carapace, thoracic sternum and pleon. Additionally, chelipeds with a spiny propodal margin and multi-lobed serial finger-teeth, otherwise characteristic for Portunoidea are found in Parazanthopsis and Palaeoxanthopsis. It remains to be investigated whether these resemblances are the result of evolutionary convergence or close phylogenetic relationships. add a blank line

The largely Kimmeridgian-Tithonian (Late Jurassic) aptychus Lamellaptychus rectecostatus (Peters, 1854) is considered to represent the jaw apparatus of the ammonite superfamily Haploceratoidea (Family Oppeliidae). However, here, from the Ogrodzieniec quarry (southern Poland), we present its unusual allochthonous occurrence embedded in a perisphinctid, Perisphinctes (Kranosphinctes) sp., and co-occurring with a late early Oxfordian Cordatum Subzone (Cordatum Zone) ammonite assemblage. The assemblage includes Cardioceras (Cardioceras) cf. cordatum (Sowerby), Neocampylites delmontanus (Oppel), Lissoceratoides erato (d’Orbigny), Bukowskites distortus (Bukowski), Trimarginites cf. arolicus (Oppel), Glochiceras sp., Holcophylloceras zignodianum (d’Orbigny) and Euaspidoceras (Euaspidoceras) perarmatum (Sowerby).

Biostratigraphy of the Tirgan and Taft formations (Lower Cretaceous successions) from the Kopet-Dagh Basin (NE Iran) and Yazd Block (Central Iran) has been described using the benthic foraminifera and colomiellids, which calibrated with the stable isotope records. They have demonstrated that ages at the base and top of the formations are diachrone, and these successions start in the Berriasian? or the lower Valanginian and end in the upper Aptian or the Albian. Evidence for this diachrony in ages has been provided by geometry of the Tirgan and Taft formations, showing explicit onlap patterns for the deposits. Furthermore, comments have been recently published on some benthic foraminifera and age models of the Tirgan and Taft formations by Schlagintweit (2021). Here, we explain about accuracy of the palaeontology of these species and demonstrate that discussion on the age models is wrongly addressed.

During the 20^th century, the first dinosaur tracks of the Causses Basin were identified at Saint-Laurent-de-Trèves, in the Parc National des Cévennes (southern France). A recent excavation reveals a new theropod tracksite in the Hettangian deposits from Le Mazel, 2 km from the historical tracksite at Saint-Laurent-de-Trèves. The tracks are here described combining a biometric approach and 3D imaging photogrammetry. The main track-bearing surface bears 64 in situ tridactyl footprints preserved as concave epireliefs. Two morphotypes were identified, a “Grallatorid” morphotype and a “Kayentapus” morphotype. Footprints belonging to the first morphotype are closely similar to Grallator lescurei, Grallator minusculus, and Grallator sauclierensis. This study shows the difficulty to distinguish quite similar tridactyl tracks from an ichnotaxonomic point of view and highlights the importance of detailed biometric comparisons. Tracks are preserved in a brown to yellowish dolomudstone showing abundant cryptalgal laminites and mud cracks. These deposits were accrued in shallow environments such as intertidal and supratidal zones of a tidal flat.

Calissounemys matheroni gen. et sp. nov. (Testudines) is described on the basis of a skull and shell elements from the Upper Cretaceous of Var, southern France. This new taxon is assigned to the family Compsemydidae and characterized by a thick-boned, robust skull, a shallow temporal emargination, a crista supraoccipitalis not extending beyond the posterior edge of the skull roof, large nasals meeting along the midline for their full length; frontals retracted from the orbital margin, absence of a cheek emargination, a large jugal forming a substantial part of the orbital margin, absence of a secondary palate and an uneven upper triturating surface; and the shell with vertebral 1 clearly wider than vertebrals 2-3, with the lateral margins strongly divergent towards the anterior border and wider than long vertebrals 2-3. This find increases the diversity of the Late Cretaceous turtle fauna from southern France, and fills a stratigraphical gap in the fossil record of Compsemydidae between the Early Cretaceous and the Paleocene in Europe.