Romain Vullo

Découverte d’un dépôt paralique à bois fossiles, ambre insectifère et restes d’Iguanodontidae (Dinosauria, Ornithopoda) dans le Cénomanien inférieur de Fouras (Charente-Maritime, Sud-Ouest de la France)

Resume Un gisement paralique inedit, d’âge Cenomanien inferieur, avec du bois fossile, de l’ambre insectifere et des restes de vertebres, a ete decouvert sur l’estran de la presqu’ile de Fouras (Charente-Maritime, France), a la suite d’une tempete qui a temporairement ote du littoral les nappages de cordons sableux et de vasieres. L’assemblage de bois fossiles contient trois taxons de coniferes ( Agathoxylon , Podocarpoxylon , Brachyoxylon ) et un Ginkgoxylon . Les insectes de l’ambre correspondent a des Dipteres, des Hymenopteres et des Homopteres. Les restes de vertebres sont principalement representes par des carapaces de tortues terrestres (Solemydidae), des vertebres de serpents ( Simoliophis ) et des ossements de dinosaures, appartenant probablement au genre Iguanodon . Pour citer cet article : D. Neraudeau et al., C. R. Palevol 2 (2003).

Un faciès de type falun dans le Cénomanien basal de Charente-Maritime (France)

Resume Des depots calcareo-sableux et coquilliers non consolides du Cenomanien basal charentais (SO France), riches en mollusques, en echinodermes et en microrestes de vertebres, sont definis comme un exemple remarquable de faluns cretaces. Une description lithologique de ces faluns cenomaniens est proposee pour deux gisements de reference (Archingeay et Cadeuil, Charente-Maritime) et l’inventaire de leur faune caracteristique est detaille, notamment pour les mollusques, les echinodermes et les vertebres. Les caracteristiques lithologiques et faunistiques de ces faluns cenomaniens sont ensuite interpretees en termes paleogeographiques et paleoclimatiques.

The oldest modern therian mammal from Europe and its bearing on stem marsupial paleobiogeography

We report the discovery of mammalian tribosphenic teeth from the basal Cenomanian of southwestern France that we refer to a new primitive marsupial-like form identified as a basal taxon of Marsupialiformes, a new clade recognized here to include the crown group Marsupialia and primitive stem lineages more closely related to Marsupialia than to Deltatheroida. Arcantiodelphys marchandi gen et sp nov. shares several significant marsupial-like features (s.l.) with marsupialiform taxa known from the North American Mid-Cretaceous. Among marsupialiforms, it shows a closer resemblance to Dakotadens. This resemblance, which is plesiomorphic within “tribotherians,” makes Arcantiodelphys one of the most archaic known Marsupialiformes. Moreover, Arcantiodelphys is characterized by an original and precocious crushing specialization. Both the plesiomorphic and autapomorphic characteristics of Arcantiodelphys among Marsupialiformes might be explained by an Eastern origin from Asian stem metatherians, with some in situ European evolution. In addition, the presence of a mammal with North American affinities in western Europe during the early Late Cretaceous provides further evidence of a large Euramerican biogeographical province at this age or slightly before. Concerning the paleobiogeographical history of the first stem marsupialiforms during the Albian–Cenomanian interval, 2 possible dispersal routes from an Asian metatherian ancestry can be proposed: Asia to Europe via North America and Asia to North America via Europe. The main significance of the Archingeay-Les Nouillers mammal discovery is that it indicates that the beginning of the stem marsupialiforms history involved not only North America but also Europe, and that this early history in Europe remains virtually unknown.

DINOSAUR TEETH FROM THE CENOMANIAN OF CHARENTES, WESTERN FRANCE: EVIDENCE FOR A MIXED LAURASIAN-GONDWANAN ASSEMBLAGE

Abstract The teeth of six dinosaur taxa (Carcharodontosauridae indet., Dromaeosauridae indet., Troodontidae indet., Brachiosauridae indet., Iguanodontoidea indet., and Nodosauridae indet.) are identified and described from the early Cenomanian of the Charentes region, western France. The composition and paleoecology of this coastal, insular fauna is discussed. The Charentes dinosaur assemblage shares affinities with Asiamerican and Gondwanan faunas. This clarifies and highlights the role of the European islands in the paleobiogeography of Cretaceous dinosaurs.

Amber, plant and vertebrate fossils from the Lower Cenomanian paralic facies of Aix Island (Charente-Maritime, SW France)

ABSTRACT Lower Cenomanian paralic facies outcrop widely on Aix Island (Charente-Maritime, France). Since the beginning of the 19th century, there has been repeated GEODIVERSITAS 2009 31 (1) mentions of abundant fossil wood and amber from this locality, with particular focus on the wood when amber remained poorly studied. New investigations beginning 8 years ago have led to the discovery of additional fossil material, including vertebrate remains and the first fossil amber inclusions. This paper provides a sedimentological, stratigraphical and palaeontological description of the local Lower Cenomanian section, and the fossil assemblages are discussed in a wider palaeoenvironmental context.

The early evolution of feathers: fossil evidence from Cretaceous amber of France

The developmental stages of feathers are of major importance in the evolution of body covering and the origin of avian flight. Until now, there were significant gaps in knowledge of early morphologies in theoretical stages of feathers as well as in palaeontological material. Here we report fossil evidence of an intermediate and critical stage in the incremental evolution of feathers which has been predicted by developmental theories but hitherto undocumented by evidence from both the recent and the fossil records. Seven feathers have been found in an Early Cretaceous (Late Albian, ca 100 Myr) amber of western France, which display a flattened shaft composed by the still distinct and incompletely fused bases of the barbs forming two irregular vanes. Considering their remarkably primitive features, and since recent discoveries have yielded feathers of modern type in some derived theropod dinosaurs, the Albian feathers from France might have been derived either from an early bird or from a non-avian dinosaur.

A Cretaceous eutriconodont and integument evolution in early mammals

The Mesozoic era (252–66 million years ago), known as the domain of dinosaurs, witnessed a remarkable ecomorphological diversity of early mammals. The key mammalian characteristics originated during this period and were prerequisite for their evolutionary success after extinction of the non-avian dinosaurs 66 million years ago. Many ecomorphotypes familiar to modern mammal fauna evolved independently early in mammalian evolutionary history. Here we report a 125-million-year-old eutriconodontan mammal from Spain with extraordinary preservation of skin and pelage that extends the record of key mammalian integumentary features into the Mesozoic era. The new mammalian specimen exhibits such typical mammalian features as pelage, mane, pinna, and a variety of skin structures: keratinous dermal scutes, protospines composed of hair-like tubules, and compound follicles with primary and secondary hairs. The skin structures of this new Mesozoic mammal encompass the same combination of integumentary features as those evolved independently in other crown Mammalia, with similarly broad structural variations as in extant mammals. Soft tissues in the thorax and abdomen (alveolar lungs and liver) suggest the presence of a muscular diaphragm. The eutriconodont has molariform tooth replacement, ossified Meckel’s cartilage of the middle ear, and specialized xenarthrous articulations of posterior dorsal vertebrae, convergent with extant xenarthran mammals, which strengthened the vertebral column for locomotion.

Taxonomic Composition and Trophic Structure of the Continental Bony Fish Assemblage from the Early Late Cretaceous of Southeastern Morocco

The mid-Cretaceous vertebrate assemblage from south-eastern Morocco is one of the most diversified continental vertebrate assemblages of this time worldwide. The bony fish component (coelacanths, lungfishes and ray-finned fishes) is represented by relatively complete specimens and, mostly, by fragmentary elements scattered along 250 kilometres of outcrops. Here we revisit the bony fish assemblage by studying both isolated remains collected during several fieldtrips and more complete material kept in public collections. The assemblage comprises several lungfish taxa, with the first mention of the occurrence of Arganodus tiguidiensis, and possibly two mawsoniid coelacanths. A large bichir cf. Bawitius, is recorded and corresponds to cranial elements initially referred to ‘Stromerichthys’ from coeval deposits in Egypt. The ginglymodians were diversified with a large ‘Lepidotes’ plus two obaichthyids and a gar. We confirm here that this gar belongs to a genus distinctive from Recent gars, contrary to what was suggested recently. Teleosteans comprise a poorly known ichthyodectiform, a notopterid, a probable osteoglossomorph and a large tselfatiiform, whose cranial anatomy is detailed. The body size and trophic level for each taxon are estimated on the basis of comparison with extant closely related taxa. We plotted the average body size versus average trophic level for the Kem Kem assemblage, together with extant marine and freshwater assemblages. The Kem Kem assemblage is characterized by taxa of proportionally large body size, and by a higher average trophic level than the trophic level of the extant compared freshwater ecosystems, but lower than for the extant marine ecosystems. These results should be regarded with caution because they rest on a reconstructed assemblage known mostly by fragmentary remains. They reinforce, however, the ecological oddities already noticed for this mid-Cretaceous vertebrate ecosystem in North Africa.

Anuran and Squamate Remains from the Cenomanian (Late Cretaceous) of Charentes, Western France

ABSTRACT New remains of an anuran and various squamate reptiles have been recovered from Cenomanian paralic deposits of Charentes (southwestern France). Remains are not abundant, yet they make up one of the most diverse Cenomanian assemblages and the most diverse one from Europe. Nine or 10 taxa are present. Precise taxonomic assignment of most of them is not always possible, even at family level; however, the mosasauroid Carentonosaurus mineaui, the snake Simoliophis rochebrunei, as well as a possible dolichosaurid lizard are identified. At least two taxa are new, but they cannot be named on the basis of the available material. Among the fossils are an anuran and terrestrial lizards that rank among the very scarce ones from the Cenomanian. In addition, three distinct snakes are among the oldest ones. The faunas from the Cenomanian of Charentes are mixtures of terrestrial and predominantly marine taxa.

Mammalian hairs in Early Cretaceous amber

Two mammalian hairs have been found in association with an empty puparium in a ∼100-million-year-old amber (Early Cretaceous) from France. Although hair is known to be an ancestral, ubiquitous feature in the crown Mammalia, the structure of Mesozoic hair has never been described. In contrast to fur and hair of some Jurassic and Cretaceous mammals preserved as carbonized filaments, the exceptional preservation of the fossils described here allows for the study of the cuticular structure. Results show the oldest direct evidence of hair with a modern scale pattern. This discovery implies that the morphology of hair cuticula may have remained unchanged throughout most of mammalian evolution. The association of these hairs with a possible fly puparium provides paleoecological information and indicates peculiar taphonomic conditions.