Annales de Paleontologie最新文献

Whereas Middle Jurassic gastropods are very well known in Europe and other regions of the world, these faunas have been much less studied from northern Africa and most contributions available in literature have been based on relatively well-preserved material. Except a little lower Bajocian fauna from the Central High Atlas (Morocco) described at the turn of the 21th century, nothing is known about the Middle Jurassic gastropods of the southwestern Tethyan margin. The present paper aims to update the systematics of two vetigastropod species: Obornella cf. granulata (Sowerby, 1818) and Ambercyclus ornatus (Sowerby, 1819) recently found in the upper Bajocian succession of the Ksour Mountains (Tniet el Klakh Formation) at western Saharan Atlas (northern Algeria). The new Ambercyclus material found in well-preserved conditions confirms the absence of umbilicus in Ambercyclus; thus, we emend the original generic diagnosis. The specimens of Obornella cf. granulata and Ambercyclus ornatus represent the first occurrence of both genera and species in the upper Bajocian marine deposits of the western Saharan Atlas, and provide new taxonomic and palaeobiogeographic information about Middle Jurassic vetigastropods in Algeria.

A new species of Archiaciidae, A. ramitaensis nov. sp., has been discovered in the late Cenomanian deposits of Syria. The species is described and compared to other Archiacia species previously known. The palaeobiogeographical distribution of archiaciids and their palaeoecological affinities are discussed.

The collection of Mesozoïc turtles conserved in the Museum of Le Havre is revised, being enhanced after the destruction which occurred during the World War II. The new purchases, including two new Jurassic (Lower Kimmeridgian) taxa of the family Plesiochelyidae, from the Cap de la Hève and Bléville respectively, are compared to the previously described turtle and now destroyed remains of the Le Havre area. On the one hand, Globochelus lennieri n. g., n. sp., from the basal Kimmeridgian Baylei biozone is the oldest plesiochelyid species named from the Upper Jurassic, that we dedicate to Lennier, in tribute to his works about geology and fossils from Le Havre. On the other hand, Tropidemys langii, from the Cymodoce biozone, is a form from the European Kimmeridgian whose presence in the Normandy region was doubted. The stratigraphic series of Le Havre, from Lennier and recent works, the sedimentology of the fossiliferous layers and the petrography of the calcareous matrix are examined, showing a littoral platform environment. The Le Havre fossil turtle record including destroyed species is reconsidered: notably the Lower Kimmeridgian plesiochelyid Plesiochelys dollfusii (Lennier), this species being clearly distinctive in the genus, and the early Cretaceous « Palaeochelys » novemcostatus Valenciennes, attibuted to a pre-employed genus but which is here confirmed as a Chelonioidea as, perhaps, “Pelobatochelys sp?”. The morphology of the shell of each plesiochelyid genus is compared. Some species previously attributed to Thalassemys are integrated in plesiochelyid genera.

The aim of the present contribution is to describe a partial fossil skull belonging to the catfish genus Sorubim. The specimen originates from the Late Miocene Ituzaingó Formation, at Paraná locality, Entre Ríos Province, Argentina. The material described here (MACN Pv-14224) was determined just to genus because the living species of Sorubim are morphologically similar. Presence of Sorubim is in concordance with the hypothesis indicating that most extant pimelodid genera were already present by the Late Miocene. Present finding constitutes the first fossil record for the genus.

The paleobiogeographic range of Eofavartia Merle, 2002 (Gastropoda: Muricidae) was until now restricted to the Eocene (Ypresian to Priabonian) of the North Atlantic Ocean and the genus seemed to become extinct after the Priabonian. The description of E. dharmai nov. sp. from the Middle Miocene from Java (Indonesia) reveals the persistence of Eofavartia during the Neogene in the Indo-Pacific region. In addition, the critical reexamination of three South Australian species previously attributed to Murexiella and Subpterynotus respectively: M. perculta Vokes, 1985 (Lower Miocene), S. antecedens (Ludbrook 1958) (Pliocene) and S. tatei (Verco 1895) (Recent) shows closer morphological affinities to E. dharmai nov. sp. and the European and North American Paleogene species of Eofavartia. The generic reassignment to Eofavartia expands the range of the genus to include South Australia. The extant E. tatei represents the last member of the genus, and is herein considered a relict species of Eofavartia.

Adequate values of environmental parameters are crucial for the long-term preservation of the fossils in a palaeontological collection. In particular, incorrect or fluctuating temperature (T) and relative humidity (RH) can affect glued or repaired materials, induce the proliferation of mould, provoke mechanical breakage, recrystallization or mineral decay. From April 2015 to March 2017, six hygrothermometers were incorporated in selected microenvironments of the Palaeontological Collection at the Facultad de Ciencias, Universidad de la República at Montevideo, Uruguay. The main aim of this study was to test the buffering effect of different enclosures compared to the ambient environmental parameters (AMB). The selected storage units were a mobile rack of shelves (C1), a cardboard box inside C1 (C2), a lidded plastic polypropylene box inside C1 (C3), a drawer in a non sealed cabinet (P), and a drawer inside a tightly sealing cabinet (G1). Maximum and minimum values of T and RH were manually gathered on a weekly basis. Linear graphs and statistical analysis (i.e. mean values, standard deviation and Kruskall-Wallis non-parametric variance analysis) were used to compare the measurements obtained. Regarding both T and RH, the more extreme values and fluctuation of these parameters were achieved in the ambient. With respect to T, all enclosures protected from Tmax variations as lower Tmax were recorded inside enclosures. With respect to RH, only C3 and G1 showed significantly lower values of RHmax than ambient values. Additionally, C3 and G1 showed an almost constant amplitude between maximum and minimum values which indicates that specimens were less exposed to fluctuations in RH. The results herein obtained show that to minimize the impact of environmental instability, it is safer for specimens to substitute cardboard by plastic containers, and closed storage units are better than open ones. In addition, sealed containers and cabinets protect the specimens from other agents of deterioration such as dust and pests.

Three turtle shells from the Middle Jurassic Xintiangou Formation of Yunyang (Chongqing, China) are described and assigned to Xinjiangchelyidae (Testudines: Eucryptodira). This is the first report of turtle remains from the Xintiangou Formation, Sichuan Basin and represents the oldest known Xinjiangchelyidae. The assemblage includes two taxa, Protoxinjiangchelys sp. and Xinjiangchelyidae indet. This discovery extends the stratigraphical distribution of Xinjiangchelyidae and improves our knowledge about the early evolution of that family. It demonstrates that by the Middle Jurassic, at the time of deposition of the Xintiangou Formation, the group was already diversified in the Sichuan Basin.

A new crocodylomorph tooth assemblage from the Lower Member of the Douiret Formation (uppermost Jurassic–lowermost Cretaceous) in southeastern Tunisia is described. These teeth have been grouped into five morphotypes based on their diagnostic morphological features. The sample includes teeth, which have not been reported until now, such as non-Machimosaurini teleosauroid teeth, and labiolingually compressed tooth crowns with cutting edges devoid of serrations. Certain minor morphometric differences have been interpreted as ontogenetic or being possibly related to the position of the teeth in the jaws. Three trophic entities have subsequently been defined on the basis of the morphological characteristics of the teeth, and a possible niche partitioning between at least three crocodylomorph taxa is highlighted for the first time in the Tataouine Basin. On the other hand, the stratigraphic context of the Douiret Formation is thoroughly discussed in order to show how stratigraphic uncertainties could significantly impact previous attempts at reconstructing the macroevolutionary history of Crocodylomorpha. The latter should be treated with caution when the stratigraphic context of the fossil bearing formation remains a subject of debate.

Our understanding of early metriorhynchid evolution, the highly specialised pelagic clade of Mesozoic crocodylomorphs, is hampered by the paucity of basal metriorhynchoids and how poorly preserved most of these fossils are. This means the transition from a ‘gharial-like’ body-plan to a ‘pseudo-dolphin-like’ one, which characterises metriorhynchoid evolution, is still poorly understood. Herein the Middle Jurassic taxon Teleidosaurus calvadosii (J.A. Eudes-Deslongchamps, 1866) is re-evaluated. The holotype of T. calvadosii was destroyed during World War Two, as were all referred specimens. All that survived are plaster casts of the holotype. However, a recently discovered specimen from the middle Bathonian of Ecouché, Normandy, France is herein referred to T. calvadosii. This specimen preserves the antorbital region, an incomplete mandible and one cervical vertebra. This specimen is designated as neotype of T. calvadosii. The new specimen allows to re-evaluate the anatomy of T. calvadosii, in particular the antorbital fenestra, which has been misunderstood. Moreover, a comparison is made between the French Middle Jurassic metriorhynchoids Teleidosaurus and Eoneustes. Both genera appear as valid and E. bathonicus is considered to be a nomen dubium.

The Agadir Basin (Moroccan Atlantic margin) is characterized by its fossil richness, including organic-walled microfossils. The palynological analysis of the middle Cretaceous succession from the Tamzargout section and EGA.1 well reveals the presence of well-preserved and diverse assemblage, rich in dinoflagellate cysts. The assemblages contain stratigraphic marker taxa and show significant chronostratigraphic events. Based on these bioevents and on the comparison with different palaeogeographic domains, a determination of age was proposed. The biogeographic characteristics of most cosmopolitan taxa in this study confirm the establishment of new oceanic communication related to the opening of the equatorial Atlantic. The Albian-Cenomanian transition has been recognized only in EGA.1 well, whereas the Aptian-Albian transition, the early-mid Albian and the mid-late Albian have been defined in both the section and the well. The recorded associations are comparable to those of neighboring deposits and those of the Tethyian and Atlantic domains. The vertical distribution of the organic matter in the sediments of the Agadir Basin and the compilation of all palaeoenvironmental proxies allowed identifying an Albian transgression with specific palaeoenvironments in each interval. Neritic marine environments alternated with short phases of continental and oceanic influence is deduced for the late Aptian-early Cenomanian in this basin. The late Aptian-early to mid Albian recorded an outer neritic palaeoenvironment under oceanic influence; the mid to late Albian showed littoral conditions during a regressive phase fluctuating to middle to outer neritic environment; finally the late Albian-early Cenomanian transition was characterized by a middle neritic palaeoenvironment under coastal influence.