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Early Cretaceous vertebrate assemblages from East Asia and particularly the Jehol Biota of northeastern China flourished during a period of highly debated climatic history. While the unique characters of these continental faunas have been the subject of various speculations about their biogeographic history, little attention has been paid to their possible climatic causes. Here we address this question using the oxygen isotope composition of apatite phosphate (δ ) from various reptile remains recovered from China, Thailand, and Japan. δ values indicate that cold terrestrial climates prevailed at least in this part of Asia during the Barremian—early Albian interval. Estimated mean air temperatures of about 10 ± 4 °C at midlatitudes (∼42 °N) correspond to present day cool temperate climatic conditions. Such low temperatures are in agreement with previous reports of cold marine temperatures during this part of the Early Cretaceous, as well as with the widespread occurrence of the temperate fossil wood genus Xenoxylon and the absence of thermophilic reptiles such as crocodilians in northeastern China. The unique character of the Jehol Biota is thus not only the result of its evolutionary and biogeographical history but is also due to rather cold local climatic conditions linked to the paleolatitudinal position of northeastern China and global icehouse climates that prevailed during this part of the Early Cretaceous.

A chevron bone from an Early Bathonian oolitic limestone in the Ardennes (NE France) is referred to the sauropod dinosaur Cetiosaurus Owen, previously known from the Middle Jurassic of England, on the basis of its rod-like distal end. This is the first well attested occurrence of Cetiosaurus in France. The presence of Cetiosaurus remains in the Bathonian of both Oxfordshire and the Ardennes is explainable by the fact that these regions were situated on the margin of the London-Brabant Massif land area, on which sauropod populations apparently lived. Contrary to the condition in other sauropods in insular environments, there is no evidence of dwarfism in Cetiosaurus from the London-Brabant Massif, probably because this emergent area was connected to the much larger Fenno-Scandian Shield.

Journal en libre accès ; PDF disponible : http://www.mnhn.fr/museum/front/medias/publication/33834_g2011n1a2.pdf; International audience; Les niveaux mésozoïques du bassin de Muang Phalan au Laos ont livré des restes d'organismes continentaux (vertébrés, mollusques, bois). Les bois avaient été rapprochés d'une espèce connue dans le Lias du Danemark, Brachyoxylon rotnaense Mathiesen, alors que les vertébrés indiquaient plutôt le milieu du Crétacé. Une révision du matériel type de B. rotnaense, de celui de son synonyme taxonomique supposé Simplicioxylon hungaricum Andreánszky, des échantillons lao et de matériel nouveau thaïlandais permet de confirmer la synonymie taxonomique, d'infirmer le rapprochement du matériel lao et de l'espèce européenne et enfin de reconnaître une nouvelle espèce regroupant le matériel lao et thaï, décrite ici sous le nom de B. serrae n. sp. Cette nouvelle espèce de Brachyoxylon est caractérisée par la présence, dans la ponctuation radiale, de groupes de ponctuations contiguës très aplaties et de paires de ponctuations opposées dans de longues files unisériées araucariennes. Notre révision permet de lever l'ambiguïté stratigraphique et confirme la singularité biogéographique de la Péninsule indosinienne au Crétacé inférieur.

After more than ten years of Thai-French research, the Thai dinosaur record, from the continental rocks of the Khorat Plateau, is, to date, the best in Southeast Asia. The oldest evidence consists of footprints of small dinosaurs from the Middle to Late Jurassic Phra Wihan Formation. The most varied dinosaur assemblage hitherto found in Thailand comes from the Late Jurassic Sao Khua Formation; it is dominated by sauropods, but also includes various theropods. Large theropod footprints are known from the Early Cretaceous Phu Phan Formation. Theropods and the primitive ceratopsian Psittacosaurus occur in the Aptian-Albian Khok Kruat Formation.

International audience; In order to investigate mid-Cretaceous terrestrial climates of low paleolatitudes, Moroccan, Tunisian and Brazilian vertebrate apatites have been analyzed for their oxygen and carbon isotope compositions of phosphates (delta(18)O(p)) and carbonates (delta(18)O(c), delta(18)C(c)). At each site, coexisting theropod dinosaurs, titanosaurid sauropods, pterosaurs, crocodilians, turtles and fish have distinct delta(18)O(p) and delta(18)C(c) values reflecting their ecologies, diets and foraging environments. Oxygen isotope compositions of surface waters (delta(18)O(w)) estimated from turtle and crocodile delta(18)O(p) values range from -5.0 +/- 1.0 parts per thousand to -2.4 +/- 1.0 parts per thousand, which do not differ from mean annual rainwater values occurring today under inter-tropical sub-arid to arid climates. High water temperatures ranging from 21 +/- 6 degrees C to 34 +/- 2 degrees C deduced from fish delta(18)O(p) values are in agreement with those published for mid-Cretaceous low latitudes. Temporary or seasonal droughts are inferred from high delta(18)O(p) values of lungfish teeth, even though lower reptile delta(18)O(p) values suggest the use of distinct and most likely larger or regularly renewed bodies of water. Environmental conditions of the studied low latitude regions during the Aptian-Cenomanian interval were somewhat similar to those experienced today under semi-arid to arid tropical or equatorial climates, but with higher mean surface temperatures than present-day ones

Fossils of vertebrates have been found in great abundance in the continental and marine early Late Cretaceous sediments of Southeastern Morocco for more than 50 years. About 80 vertebrate taxa have so far been recorded from this region, many of which were recognised and diagnosed for the first time based on specimens recovered from these sediments. In this paper, we use published data together with new field data to present an updated overview of Moroccan early Late Cretaceous vertebrate assemblages. The Cretaceous series we have studied encompasses three Formations, the Ifezouane and Aoufous Formations, which are continental and deltaic in origin and are often grouped under the name “Kem Kem beds”, and the Akrabou Formation which is marine in origin. New field observations allow us to place four recognised vertebrate clusters, corresponding to one compound assemblage and three assemblages, within a general temporal framework. In particular, two ammonite bioevents characterise the lower part of the Upper Cenomanian (Calycoceras guerangeri Zone) at the base of the Akrabou Formation and the upper part of the Lower Turonian (Mammites nodosoides Zone), that may extend into the Middle Turonian within the Akrabou Formation, and allow for more accurate dating of the marine sequence in the study area. We are not yet able to distinguish a specific assemblage that characterises the Ifezouane Formation when compared to the similar Aoufous Formation, and as a result we regard the oldest of the four vertebrate “assemblages” in this region to be the compound assemblage of the “Kem Kem beds”. This well-known vertebrate assemblage comprises a mixture of terrestrial (and aerial), freshwater and brackish vertebrates. The archosaur component of this fauna appears to show an intriguingly high proportion of large-bodied carnivorous taxa, which may indicate a peculiar trophic chain, although collecting biases alter this palaeontological signal. A small and restricted assemblage, the OT1 assemblage, possibly corresponds to a specific, localised ecosystem within the Kem Kem beds compound assemblage. Microfossils and facies from the Aoufous Formation, corresponding to the top of the compound assemblage, provide evidence of extremely abiotic conditions (hypersalinity), and thus of great environmental instability. At the base of the Akrabou Formation the first ammonite bioevent, Neolobites, corresponds to the onset of the marine transgression in the early Late Cenomanian while the Agoult assemblage (Late Cenomanian?) contains a variety of small fish species that have Central Tethyan affinities. Finally, the youngest Mammites bioevent in the late Early Turonian corresponds to a deepening of the marine environment: this sequence is isochronous with the Goulmima assemblage, a diverse collection of fish and other marine taxa, and shows affinities with taxa from the South Atlantic, the Central Tethys and the Western Interior seaway of North America, and further highlights the biogeographical importance of these North African Late Cretaceous assemblages.

Warm-Blooded Reptiles?Existing reptiles are not thought to be endothermic, but what about extinct species? Three large extinct swimming reptiles, the ichthyosaurs, plesiosaurs, and mosasaurs, were active predators in the Mesozoic oceans.Bernardet al.(p.1379; see the Perspective byMotani) investigated their metabolism by analyzing the oxygen isotopes in their teeth, compared with fish in deposits from a variety of ocean environments. The data imply that the ichthyosaurs and plesiosaurs, which were both pursuit predators, probably controlled their own temperature. The data for the mosasaurs, which are thought to have hunted by ambush, are more equivocal.

International audience; Spinosaurs were large theropod dinosaurs showing peculiar specializations, including somewhat crocodile-like elongate jaws and conical teeth. Their biology has been much discussed, and a piscivorous diet has been suggested on the basis of,jaw as well as tooth morphology and stomach contents. Although fish eating has been considered plausible, an aquatic or semiaquatic lifestyle has seldom been suggested because of the apparent lack of corresponding adaptations in the postcranial skeleton of spinosaurs, which on the whole is reminiscent of that of other large terrestrial theropods. On the basis of the oxygen isotopic composition of their phosphatic remains compared with those of coexisting terrestrial theropod dinosaurs and semiaquatic crocodilians and turtles, we conclude that spinosaurs had semiaquatic lifestyles, i.e., they spent a large part of their daily time in water, like extant crocodilians or hippopotamuses. This result sheds light on niche partitioning between large predatory dinosaurs, since spinosaurs coexisted with other large theropods such as carcharodontosaurids or tyrannosaurids. The likely ichlhyophagy and aquatic habits of spinosaurids may, have allowed them to coexist with other large theropods by reducing competition for food and territory.

Un tibia-fibula de pterosaure est decrit en provenance de schistes argileux toarciens ("Marne de Flize") a proximite de la ville de Charleville-Mezieres (Ardennes, NE de la France). La morphologie de cet element, en particulier la fibula reduite partiellement fusionnee au tibia, suggere qu'il appartient au rhamphorhynchide Dorygnathus, bien represente dans les Posidonienschiefer d'Allemagne et aussi signale dans le Toarcien de Nancy (Est de la France).

Sauropods were a very successful group of dinosaurs during the Jurassic and Cretaceous periods, but their earlier history is poorly known. Until now, the earliest reported sauropod bones were from the Early Jurassic1,2,3, and the only tentative evidence of earlier sauropods was in the form of controversial footprints4,5. Here we report the discovery of an incomplete sauropod skeleton from the Late Triassic period of Thailand, which provides the first osteological evidence of pre-Jurassic sauropods. This dinosaur is markedly different from prosauropods and substantiates theoretical predictions that there was a fairly long period of sauropod evolution during the Triassic.

International audience; An isolated dinosaur vertebra from the marine deposits of the Maastrichtian type area, near the city of Maastricht (The Netherlands), collected during the 19th century and kept in the palaeontological collection of the Museum für Naturkunde in Berlin, is described as a caudal vertebra of a hadrosaurid ornithopod. Although it cannot be identified with greater accuracy, this specimen is an addition to the still scanty, but growing, record of non-avian dinosaurs from the Maastrichtian type area. This record is heavily dominated by hadrosaurs, which probably reflects a real abundance of this group of dinosaurs in the Late Maastrichtian of Europe.

A review of the main Late Cretaceous dinosaur localities of Europe shows that stratigraphic correlations are often problematic. Dinosaur occurrences in marine sediments in the Netherlands, Belgium, France and Crimea are usually well dated, but remains from such sites are often incomplete and difficult to identify with satisfactory accuracy. Dinosaur localities in nonmarine series in Portugal, Spain, France and Transylvania yield better material, but precise dating is often difficult. The Muthmannsdorf fauna of Austria is an exception, the dinosaur-bearing beds being intercalated in the essentially marine Gosau Beds; an early Campanian age can thus be deduced. Available evidence suggests that the main Late Cretaceous dinosaur localities of Europe range in age from early Campanian to late Maastrichtian. To judge from comparison with the North American record, some evolution must have occurred during this fairly long time span. Preliminary observations suggest that evolutionary changes are traceable within the Campanian to Maastrichtian dinosaur communities of Europe.

A paleomagnetic study of rocks from the northern foot of the Tien Shan and the southern border of the Dzungar Basin, east of Urumqi (44.2°N, 86.0°E), spanning ages from middle Jurassic to early Tertiary was carried out to constrain the tectonic evolution in central Asia since Mesozoic time. Five middle Jurassic sites reveal a remagnetized direction close to the present Earth field in geographic coordinates: D = 6.6°, I = 72.6° (α_(95) = 7.4°). Thirteen out of 17 upper Jurassic and lower Cretaceous sites yield a characteristic direction (stratigraphic coordinates) of D = 12.7°, I = 48.6° (α_(95) = 5.5°). Nine of 16 upper Cretaceous and lower Tertiary sites provide a characteristic direction of D = 12.5°, I = 51.3° (α_(95) = 6.9°). The latter two directions pass fold and reversal tests. The pole positions are close to each other and to the Besse and Courtillot [1989, 1990] Eurasian apparent polar wander path, for ages ranging from 130 to 70 Ma. However, the difference in paleolatitudes amounts to about 5.9° ± 3.7°, which could indicate significant continental shortening in the Altai Mountains and perhaps further north, subsequent to India-Asia collision. The pole positions from the Dzungar Basin are close to those found for the Tarim [Li et al., 1988a], leading to an insignificant paleolatitude difference (3.0° ± 6.9°), but showing a larger difference in declination (8.6° ± 8.7°). These paleomagnetic results are compatible with a model of heterogeneous deformation in the western part of the collision zone between India and Siberia. A significant shortening in the Altai, a slight counterclockwise rotation of the Dzungar block, the westward-increasing shortening in the Tien Shan with attendant clockwise rotation of the Tarim block are all consistent with this model, in which Tibet, the Tien Shan and the Altai undergo differential strain along strike in a relay fashion, with the total India-Siberia convergence remaining approximately constant.

For several years, palaeoecological research has been conducted on micritic limestones of late Kimmeridgian age in the southern Jura Mountains. The sedimentary environment is that of a lagoon with an irregular bottom, which was repeatedly exposed. Between two stages of lime deposition, a microbial mat grew over the muddy surface, giving cohesion to the sediment, restraining erosion and preserving fossil remains and reptile tracks. Various structures at the microbial mat surface can be observed : crescentic wavy, radial wavy, torn, petee and mixed structures. They imply the presence of desiccation periods and a slight bottom slope leading to a downward sliding of the microbial mat. Such features may also be generalised to explain superficial microbial structures of other shallow carbonate-mud environnements.

Resume Les affinites des dinosaures theropodes du Cretace superieur d'Europe sont discutees; la plupart des restes sont constitues de dents isolees ou d'ossements peu diagnostiques: Megalosaurus pannoniensis Seeley , M. lonzeensis Dollo et M. hungaricus Nopcsa sont des nomina dubia; il est recommande de les considerer comme des Theropoda indetermines. Trois pieces europeennes seulement sont determinables: elles sont rapportees a la famille des Abelisaurides. Tarascosaurus salluvicus nov. gen., nov. sp.., est le premier dinosaure decrit du Cretace superieur (Campanien inferieur) du Synclinal du Beausset. Il est compare a d'autres theropodes d'Europe et d'Amerique du Sud et rapporte aux Abelisaurides.

Teeth from the Early Cretaceous Napai Formation of Fusui County, Guangxi Zhuang Autonomous Region (South China), initially described as the sauropterygian Sinopliosaurus fusuiensis, are redescribed as belonging to a spinosaurid theropod closely allied to Siamosaurus suteethorni, from the Early Cretaceous of Thailand. This identification extends to China the geographical range of Asian spinosaurs, previously reported from Thailand and Japan.

Hitherto unpublished crocodylian remains, including four skull fragments, from the lignite-bearing localities of Valdonne and Fuveau (Santonian–Campanian), south-eastern France, are described. They complement the original material of ‘Crocodilus affuvelensis’ described by Matheron (1869) and Repelin (1930). Based on overlapping specimens, available elements of the rostrum, the palate, the skull table, the mandible and the pterygoid can be shown to belong to a single taxon, for which a reconstruction is proposed. Designation of a neotype has been proposed to the ICZN committee. A new genus, Massaliasuchus, is proposed here to designate the crocodylian originally described as Crocodilus affuvelensis. This crocodylian presents affinities with basal alligatoroids and complements the picture of crocodylian diversity during the Late Cretaceous in the European archipelago. Massaliasuchus affuvelensis is compared with other European taxa and with basal alligatoroids from North America. The putative basal position of Massaliasuchus as well as its early geological age suggest that the geographical origin of the Alligatoroidea is still uncertain. © 2008 The Linnean Society of London, Zoological Journal of the Linnean Society, 2008, 152, 567–580.

Tong Haiyan, Claude Julien, Suteethorn Varavudh, Naksri Wilailuck, Buffetaut Éric. Turtle assemblages of the Khorat Group (Late Jurassic-Early Cretaceous) of NE Thailand and their palaeobiogeographical significance. In: Documents des Laboratoires de Géologie, Lyon, n°164, 2008. Mid-Mesozoic life and environments. Cognac (France), June 24th-28th 2008. p. 85.

Since the early beginnings of the scientific investigation of the diversity of the living world, some four hundred years ago, a large number of species have become extinct, in all parts of the world, because of human intervention, and there is widespread concern about a devastating amplification of this trend in the near future. Extinction, however, is of course not a recent phenomenon linked to human activities. The main achievement of early palaeontologists, at the beginning of the nineteenth century, was to demonstrate beyond all doubt the reality of extinction without human intervention, during the geological past (Buffetaut, 1987). The complete extinction of species had long been considered an impossibility, mainly on religious grounds (it contradicted the concept of the plenitude and perfection of divine creation). Accumulating fossil evidence led scientists such as Blumenbach and Cuvier to the inescapable conclusion that countless species had disappeared in the course of geological time, well before the appearance of man. It thus seems that any reflexion on future extinctions should also take the past record of extinctions into account, for the simple reason that it may be impossible to find an analogue to the current wave of extinctions within the time span covered by human history. The "philosophical" justification of such

A critical analysis of the fossil vertebrate record across the Cretaceous-Tertiary boundary shows that the available evidence is far less accurate than that concerning invertebrates and microfossils. Far-reaching conclusions have been drawn from generalisations about vertebrate extinctions in the continental realm based on the local record from western North America, but little is known about patterns of terminal Cretaceous vertebrate extinctions in other parts of the world, and even the western North American record is ambiguous. Despite this unsatisfactory record, it clearly appears that terminal Cretaceous vertebrate extinctions were highly selective, with some groups (e.g. dinosaurs) becoming completely extinct, whereas others seem to be virtually unaffected. This argues against devastating catastrophes of the kind postulated by some recent impact scenarios. However, the survival of groups known to be sensitive to climatic deterioration (such as crocodilians and other non-dinosaurian reptiles) indicates that alternative hypotheses involving gradual but fairly important climatic changes on a world-wide scale are not convincing either. The pattern of extinction and survival among vertebrates across the Cretaceous-Tertiary boundary may be explained as a consequence of the disruption of some food chains following a crisis in the plant kingdom, which itself may have been the result of the atmospheric consequences of unusual extraterrestrial or internal events.

Four caudal vertebrae from the Cyprina brongniarti zone (Lower Portlandian) of Ville-en-Blaisons (Haute-Marne, eastern France) are described and referred to a sauropod dinosaur belonging either to the Camarasauridae or to the Brachiosauridae. The bones were found in a shallow marine limestone and were probably derived from a floating carcass.

International audience; Oxygen isotope compositions of phosphate (δ18Op) were measured in tooth enamel from captive and wild individuals of 8 crocodilian species. A rough linear correlation is observed between the δ18Op of all the studied species and the oxygen isotope composition of ambient water (δ18Ow). Differences in mean air temperature, diet and physiology could contribute significantly to the large scatter of δ18Op values. The combination of these parameters results in a fractionation equation for which the slope (0.82) is lower than that expected (≥1) from predictive model equations that assume temperature and diet as fixed parameters. Taking into account large uncertainties, the observed oxygen isotope fractionation between phosphate and ambient water does not statistically differ from that formerly established for aquatic turtles. Case studies show that δ18Op values of fossil crocodile tooth enamel can be used to discriminate between marine and freshwater living environments within a precision of about ±2‰ only.

A malformed embryonic or neonate choristoderan reptile from the Lower Cretaceous Yixian Formation of northeastern China is described. The tiny skeleton exhibits two heads and two necks, with bifurcation at the level of the pectoral girdle. In a fossil, this is the first occurrence of the malformation known as axial bifurcation, which is well known in living reptiles.

International audience; The much debated question of dinosaur thermophysiology has not yet been conclusively solved despite numerous attempts. We used the temperature-dependent oxygen isotope fractionation between vertebrate body water (δ18Obody water) and phosphatic tissues (δ18Op) to compare the thermophysiology of dinosaurs with that of non-dinosaurian ectothermic reptiles. Present-day δ18Op values of vertebrate apatites show that ectotherms have higher δ18Op values than endotherms at high latitudes due to their lower body temperature, and conversely lower δ18Op values than endotherms at low latitudes. Using a data set of 80 new and 49 published δ18Op values, we observed similar and systematic differences in δ18Op values (Δ18O) between four groups of Cretaceous dinosaurs (theropods, sauropods, ornithopods and ceratopsians) and associated fresh water crocodiles and turtles. Expressed in terms of body temperatures (Tb), these Δ18O values indicate that dinosaurs maintained rather constant Tb in the range of endotherms whatever ambient temperatures were. This implies that high metabolic rates were widespread among Cretaceous dinosaurs belonging to widely different taxonomic groups and suggest that endothermy may be a synapomorphy of dinosaurs, or may have been acquired convergently in the studied taxa.

The global devastation of ecosystems as a consequence of a meteorite impact 65 million years ago is clearly detectable in palaeontological and geological records all over the globe. Here we compare and contrast the consequences of the impact expressed in the vegetation, vertebrate fossil record and geological signatures left by the devastation, including information from new proximal KT boundary exposures and new palynological data. The geological evidence of the Chicxulub impact crater shows that the target rock was composed by higher percentages of anhydrite (sulfur source) than carbonates. Atmospheric radiative transfer models suggest that the vaporized target rock rapidly converted into sulfuric acid H2SO4 aerosols where it was injected in the stratosphere by the force of the impact and globally distributed. It took at least 10 years for the H2SO4 to dissipate, making the Earth’s atmosphere opaque to sunlight, leading to a reduction of solar transmission to 10–20% of normal for that period.

International audience; The discovery of a new elasmobranch assemblage from the Lower Cretaceous of Thailand allows expansion of the faunal list and refinement of our knowledge of the dental morphological features of some previously described taxa. The root morphology of Thaiodus is now known and a more complete description of the dentition of the genus Heteroptychodus, known formerly by a single tooth from Japan, is given. A new genus and species, Acrorhizodus khoratensis, characterized by teeth of very special morphology is described. Besides these taxa, some teeth of a genus probably close to Hybodus, but with more bulbous teeth, are present. Owing to the sedimentological characters of the deposits and the associated fauna (dinosaurs), it is probable that this elasmobranch fauna lived in a freshwater or brackish environment. The simultaneous occurrence of teeth of Heteroptychodus in Thailand and Japan favours the existence of a large continental area in south-east Asia during the Early Cretaceous.

International audience; Two sauropod teeth from an Early Cretaceous (Neocomian) fluviodeltaic sandstone near Jezzine (Southern Lebanon) are the first nonavian dinosaur remains to be reported from Lebanon. Their distinctive character places them within Brachiosauridae. The sauropod teeth from Lebanon are a significant addition to the very scanty dinosaur record from the Levant, which hitherto consisted mainly of very poorly preserved and not easily identifiable specimens. The Basal Cretaceous Sandstone of Lebanon, thus, appears to be a potentially important source of fossil vertebrate material.

International audience; Abundant well-preserved jellyfish impressions are described from the Cerin Lagerstätte (Ain, eastern France). The enclosing sediments are lithographic limestones deposited in a Late Kimmeridgian lagoon lying on an emergent reef complex. Two new taxa of Scyphozoa are proposed: Paraurelia cerinensis gen. et sp. nov. (abundant) and Paraurelia sp. A (rare), and two new taxa of Cubozoa: Bipedalia cerinensis gen. et sp. nov. (rare) and Paracarybdea lithographica gen. et sp. nov. (very rare). Rapid covering by a microbial mat helped the preservation of the animals. Many specimens of Paraurelia cerinensis are deformed by slippage down the palaeoslope, which characterizes the margin of the lagoon. Their resultant morphology and their orientation clearly indicate the downslope direction. Tentacles of Bipedalia cerinensis and Paracarybdea lithographica are also orientated according to the palaeoslope. The jellyfish were probably dead individuals occasionally introduced into the Cerin lagoon. However, another hypothesis may be considered with reference to the model of the present-day jellyfish lakes in Palau (Caroline Islands, Western Pacific). Jellyfish could have lived in the more oxygenated upper layer of water of the Cerin lagoon that allowed pelagic life. This situation could have corresponded to short periods of easier communication between the open sea and the lagoon. Jellyfish are only found in the lower beds of the lithographic limestones and their distribution illustrates the supposed evolution of the Cerin lagoon. Initially, it was deep, mainly flooded, with possibly autochthonous jellyfish and allochthonous animals indicating clear marine influence. Later, the lagoon shallowed and its sediments often emerged with marginal marine burrows and plants indicating increasing terrestrial influence.

International audience; Isolated teeth of five hybodont taxa (Hybodus sp., Parvodus sp., Lonchidion khoratensis nov. sp., Isanodus paladeji nov. gen., nov. sp., Heteroptychodus steinmanni) are described from the freshwater Sao Khua Formation of Thailand (Lower Cretaceous). This Early Cretaceous fauna appears less endemic, with some European affinities, than the hybodont fauna found in Thailand in the more recent Aptian/Albian Khok Kruat Formation. Teeth of Isanodus paladeji (Lonchidiidae) and Heteroptychodus steinmanni (Ptychodontidae) share an unusual ornamentation pattern suggesting that the origin of the family Ptychodontidae is nested among Asian Lonchidiidae.

Since the 19th century, the Campanian and Maastrichtian continental deposits of southern France have yielded numerous dinosaur remains [Le Loeuff, 1991; 1998; Buffetaut et al., 1997; Laurent et al., 1991; Allain and Suberbiola, 2003]. The ornithopod remains that have not been referred to the hadrosaurids have been systematically attributed to Rhabdodon [Buffetaut and Le Loeuff, 1991; Buffetaut et al., 1996; Garcia et al., 1999; Pincemaille-Quillévéré, 2002]. This genus, initially named by Matheron [1869] after its discovery in the lower Maastrichtian of La Nerthe (Bouches-du-Rhône), belongs to the Euornithopoda [sensu Sereno, 1999]. Rhabdodon represents the most common element of the dinosaur assemblages from the late Cretaceous of southern France [e.g. Allain and Suberbiola, 2003]. Nevertheless, since the localities have only provided some fragmentary material [Pincemaille-Quillévéré, 2002], the global morphology of this dinosaur and its phylogenetic placement within the euornithopods are still debated. The cranial morphology of Rhabdodon is particularly poorly understood due to the rarity of cranial remains preserved in the localities of southern France [Matheron, 1869; Garcia et al., 1999; Buffetaut et al., 1999; Pincemaille-Quillévéré, 2002]. Buffetaut et al. [1999] first mentioned the discovery of a braincase (M4) referred to Rhabdodon, at Massecaps, a locality close to the village of Cruzy (Hérault, France). More recently, a new braincase (MN25) has been discovered at Montplô Nord, another locality close to Cruzy (specimens M4 and MN25 are conserved in the Museum of Cruzy). Both these localities have revealed a diverse and abundant vertebrate fauna suggesting a late Campanian to early Maastrichtian age [Buffetaut et al., 1999]. These braincases are described here in an attempt to detect potential autapomorphic characters in Rhabdodon, and compared to a more complete braincase of Tenontosaurus, an euornithopod from the Lower Cretaceous of North America, considered as the sister group of Rhabdodon [Weishampel et al., 1998; 2003; Garcia et al., 1999; Pincemaille-Quillévéré, 2002], in order to determine the potential differences and synapomorphies between the occiputs of the two genera. Finally, the braincases from Cruzy are compared to those of the other euornithopods described in the literature. Specimen M4 (figs. 1–4) is incomplete but exceptionally well preserved. This braincase belongs to a juvenile individual, as shown by the numerous visible suture lines between the different cranial elements. Specimen MN25 (fig. 5) is badly deformed and attributable to an adult individual. Until now, all the ornithopods from the Upper Cretaceous of southern France have been referred either to hadrosaurs or to Rhabdodon. The Hadrosauridae show a low nuchal crest and their exoccipitals meet and form a bar on the dorsal border of the foramen magnum, excluding the supraoccipital from this border. Specimens M4 and MN25 do not present any nuchal crest and the supraoccipital participates in the dorsal border of the foramen magnum. Both braincases M4 and MN25 are therefore attributable to Rhabdodon. Specimens M4 and MN25 have been compared to the occiput of a juvenile Tenontosaurus tilletti (fig. 6 : MCZ 4205, conserved in the Museum of Comparative Zoology, Harvard University). This reveals that Tenontosaurus and Rhabdodon share numerous characters : (1) the exoccipitals form the lateral borders of the foramen magnum, its ventral border being occupied by the basioccipital; (2) the occipital condyle is partly constituted by the exoccipitals, and in the same proportions; (3) the supraoccipital is rostrally oriented; (4) the suture line located between the prootic and the laterosphenoid shows the same outline; (5) the cresta prootica starts within the paroccipital process and extends onto the opisthotic; (6) the cresta prootica is transversal and non-horizontal; (7) the distribution of the cranial nerves is homologuous along the lateral surface of the braincase. Nevertheless, the braincase of Tenontosaurus differs from that of Rhabdodon in several significant respects : (1) the exoccipitals are dorsally connected, excluding the supraoccipital from the dorsal border of the foramen magnum; (2) two small dorsal humps are present at the level of the suture of the exoccipitals; (3) the supraoccipital is excluded from the dorsal border of the foramen magnum, which gives it a triangular shape; (4) the paroccipital processes are short, laterally flattened, and wing-shaped, and are more mediodorsally oriented than in Rhabdodon; (5) the cresta prootica follows a concave line and ends up on the prootic, at the level of the opening of the trigeminal nerve; (6) the external curve of the laterosphenoids is stronger; (7) the suture between the basioccipital and the opisthotic is very clear. The first of these unshared characters suggests that Rhabdodon belongs to Norman’s [1984] ‘hypsilophodontoid’ clade and Tenontosaurus to the more evolved ‘iguanodontoid’ clade. The fusion of the exoccipitals on the dorsal border of the foramen magnum, together with other cranial adaptations, may have reduced the stress caused by a more elaborate mastication. Rhabdodon appears to have had a more primitive type of mastication. The strip formed by the reunion of the exoccipitals is less expanded dorsoventrally in Tenontosaurus tilletti than in the ‘iguanodontoid’ and ‘hadrosauroid’ clades. Tenontosaurus may therefore represent an intermediate group between the ‘hypsilophodontoid’ and ‘iguanodontoid’ clades.

It has been suggested that the eruption of the Deccan Trapps has contributed to the events of the Cretaceous-Tertiary transition as a possible cause of Iridium enrichment and/or other physicochemical disturbances. However, no precise chronological framework was available for the emplacement of these Trapps, which form one of the largest known occurrences of continental basalt flows. A joint Indian-French project, still under way, is providing more accurate informations about the chronology of the Deccan Trapps and its possible implications for Cretaceous-Tertiary boundary events.

International audience; We report on very small fossil eggs from the Lower Cretaceous of Thailand, one of them containing a theropod embryo, which display a remarkable mosaic of characters. While the surficial ornamentation is typical of non-avian saurischian dinosaurs, the three-layered prismatic structure of the eggshell is currently known only in extant and fossil eggs associated with birds. These eggs, about the size of a goldfinch's, mirror at the reproductive level the retention of small body size that was paramount in the transition from non-avian theropods to birds. The egglayer may have been a small feathered theropod similar to those recently found in China.

International audience; The last European fossil occurrence of a coelacanth is from the Mid-Cretaceous of the English Chalk (Turonian, 90 million years ago). Here, we report the discovery of a coelacanth from Late Cretaceous non-marine rocks in southern France. It consists of a left angular bone showing structures that imply close phylogenetic affinities with some extinct Mawsoniidae. The closest relatives are otherwise known from Cretaceous continental deposits of southern continents and suggest that the dispersal of freshwater organisms from Africa to Europe occurred in the Late Cretaceous.

A dentary bone containing several teeth, from the Middle Jurassic (Bathonian) of northwestern Madagascar is described as the type of a new sauropod dinosaur taxon, Archaeodontosaurus descouensi, n.g., n.sp. This taxon is characterised by the unusual combination of a dentary with a deep anterior part, as in advanced sauropods, and teeth with large serrations and a convex lingual side, which resemble the teeth of prosauropods. A more common pattern in early sauropods is the combination of a low, prosauropod-like dentary and spoon-shaped, sauropod-like teeth. Although the condition in Archaeodontosaurus descouensi strongly suggests that basal sauropods had prosauropod-like teeth, what is known of the jaw and dentition in various early and middle Jurassic sauropods indicates mosaic evolution along different paths during the early diversification of the group. Archaeodontosaurus descouensi differs from Jurassic sauropod material from Madagascar, previously described as Bothriospondylus and Lapparentosaurus, which needs revision. It appears that at least two distinct sauropods, with different tooth morphologies, are present in the Middle Jurassic of Madagascar.

International audience; Published reports of amber predating the Aptian are rare and mention only amber pieces the size of millimetric marbles. Mid Cretaceous amber records, however, show a dramatic increase in number as well as in the size of the pieces, a phenomenon which is still poorly understood. The discovery of the first Jurassic deposit with comparatively large centimetric sized pieces of amber, in southern Thailand, is significant. Taphonomy and palaeobotany indicate a dense forest surrounding a coastal lake dominated by the resin-producing Agathoxylon tree. Since the palaeoecology of other amber-producing Jurassic and Cretaceous deposits is very similar a new hypothesis needs to be sought to explain the mid Cretaceous amber boom. It is suggested here that it was the result of a geological or taphonomic bias because coastal lacustrine environments are much better preserved after the Aptian on a worldwide scale.

International audience; A vertebra collected from the Jurassic non-marine Khlong Min Formation of southern Thailand is referred to the family Euhelopodidae, a group of sauropod dinosaurs that apparently was endemic to eastern Asia during the Jurassic and Early Cretaceous, at a time when that part of the world was isolated from other land masses. The occurrence of a euhelopodid in the Jurassic of the Shan–Thai Block supports the idea of a collision of the Shan–Thai Block with the Indochina Block, thus establishing connections with ‘mainland Asia', early in the Mesozoic, probably before the Jurassic.

International audience; Il est montré qu'une vertèbre provenant de l'Albien de Mesnil-Saint-Père (Aube, E du Bassin de Paris), précédemment identifiée comme une première caudale d'un dinosaure sauropode, est en fait une vertèbre dorsale d'un grand pliosaure. Le spécimen évoque des vertèbres de l'Albien d'Angleterre et de l'Est de la France qui ont été attribuées au pliosaure Polyptychodon, taxon qui a besoin d'être révisé.–––The "sauropod" from the Albian of Mesnil-Saint-Père (Aube, France): a pliosaur, not a dinosaur.- A vertebra from the Albian of Mesnil-Saint-Père (Aube, eastern Paris Basin), previously identified as the first caudal of a sauropod dinosaur, is shown to be a dorsal vertebra of a large pliosaur. The specimen resembles vertebrae from the Albian of England and eastern France that have been referred to the pliosaur Polyptychodon, a taxon in need of revision.

A remarkable specimen has been discovered of an Early Cretaceous pterosaur that has a tooth embedded in one of its cervical vertebrae: the tooth has been identified as one from a spinosaurid theropod dinosaur. This fossil is direct evidence that spinosaurs included items other than fish in their diet.

International audience; Latitudinal variations in model biogenic apatite d18O values were calculated using fractionation equations of vertebrates and weighted rainfall y18O values along with mean annual air temperatures provided by IAEA–WMO meteorological stations. The reference equation obtained was used to compute a continental temperature gradient for the Late Campanian–Middle Maastrichtian interval by using published and new d18O values of phosphate from vertebrates. Samples are mainly tooth enamel from crocodilians and dinosaurs that lived at paleolatitudes ranging from 83 ± 4 °N (Alaska) to 32 ± 3 °S (Madagascar). The temperature gradient was less steep (0.4 ± 0.1 °C/°latitude) than the present-day one (0.6 °C/°latitude) with temperatures that decreased from about 30 °C near the equator to about -5 °C at the poles. Above 30° of paleolatitude, air temperatures were higher than at present. The validity of these results is discussed by comparison with climatic criteria inferred from paleontological, paleobotanical and sedimentological data. The latitudinal distribution of oxygen isotope compositions of continental vertebrates is potentially a powerful tool for quantifying Mesozoic terrestrial climates.