Annales de Paleontologie最新文献

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.

We report here three new elasmobranch fossil taxa from Thanetian–Lower Lutetian nearshore marine deposits of northeastern (Matam region) and central-western (Sine-Saloum region) Senegal. These three new taxa represent the oldest species of the enigmatical elasmobranch Odontorhytis, the oldest putative representatives of marine potamotrygonid, and an uncertain dasyatoid genus with the smallest grinding dentition ever described. These new taxa, representing the second Cenozoic elasmobranch remains formally described from Senegal, broaden our understanding of their evolutionary and biogeographic history in the equatorial Eastern Atlantic during this time period. Their occurrences confirm hypothesised stratigraphically correlations between the top of Matam Fm. and the base of Lam Lam Fm., refine the marine connections between these two Senegalese regions, and suggest that these genera were broadly distributed within the shallow marine settings of the equatorial Eastern Atlantic during latest Paleocene–early Middle Eocene.

Lower Devonian strata from the drill cores from Poland have yielded new Heterostraci material. One ventral shield of Toombsaspis (Traquairaspididae, Phialaspidinae) discovered in the Białopole IG-1 drill core, and a fragment of dorsal shield of cf. Paraliliaspis (Cyathaspididae, Anglaspidinae) with the impressions of internal structures from Ciepielów IG-1 are described and provide new information on paleogeographic disparity of these groups.

The Cenomanian Smail Marl Formation in the Bellezma and Aures mountains of northeastern Algeria is well exposed and rich in macroinvertebrates, including cephalopods. Twenty-five ammonite species and two nautiloid species from the Thénièt El Manchar, Djebel Metrassi and Djebel Bouarif sections are described and seven assemblage zones proposed as provisional working units: Mantelliceras mantelli–Sharpeiceras laticlavium Assemblage Zone (lower Cenomanian), Mantelliceras dixoni Assemblage Zone (uppermost lower Cenomanian), Cunningtoniceras inerme Assemblage Zone (lower middle Cenomanian), Acanthoceras rhotomagense and Acanthoceras cf. rhotomagense Assemblage Zone (middle middle Cenomanian), Acanthoceras amphibolum Assemblage Zone (upper middle Cenomanian), Acanthoceras jukesbrownei Assemblage Zone (uppermost middle Cenomanian), and Neolobites vibrayeanus Assemblage Zone (lower upper Cenomanian). The lower Cenomanian Mantelliceras mantelli–Sharpeiceras laticlavium Zone is subdivided into the Submantelliceras aumalense, Sharpeiceras schlueteri and Mantelliceras saxbii subzones. The base of the middle Cenomanian is marked by the disappearance of species of Mantelliceras and the appearance of the scleractinian coral Aspidiscus cristatus (Lamarck, 1801), associated with Cunningtoniceras inerme (Pervinquière, 1907). The middle Cenomanian contains abundant A. cristatus and species of Acanthoceras, i.e., A. cf. rhotomagense (Defrance in Brongniart, 1822), A. jukesbrownei (Spath, 1926) and A. amphibolum Morrow, 1935. An ammonite zonal scheme is then applied to the Cenomanian exposed in the Bellezma-Aures mountains located on the southern Tethys margin in Algeria.