Dinosaur

Melanin, and other pigments have recently been shown to preserve over geologic time scales, and are found in several different organisms. This opens up the possibility of inferring colours and colour patterns ranging from invertebrates to feathered dinosaurs and mammals. An emerging discipline is palaeo colour: colour plays an important role in display and camouflage as well as in integumental strengthening and protection, which makes possible the hitherto difficult task of doing inferences about past ecologies, behaviours, and organismal appearance. Several studies and techniques have been presented in the last couple of years that have described ways to characterize pigment patterns. Here, I will review the available methods and the likely applications to understand past ecologies. A golden age of colourized dinosaurs and other animals is now dawning upon us, which may elucidate the nature of ancient predator prey interactions and display structures. Also watch the Video Abstract.

The use of MC-ICP-MS for B isotopic measurements offers some advantages compared with other techniques such as the absence of interferences with atomic masses 10 and 11 and an enhanced speed of data acquisition. We have developed a fast and simple protocol for the separation by ion-exchange resins and concentration of B from natural waters, carbonates, phosphates, and silicates. Normalization of sample isotopic ratios to the NIST reference NBS 951 leads to an external reproducibility of ±0.3δ unit at 95% confidence level. The ionization yield is about 2 ions per 106 atoms of B in the analyzed solution. At least 2 μg of boron is required to obtain the above good-quality external reproducibility.Replicated analyses of Mediterranean seawater provided a δ11B of 40.26±0.29 (n=11). Aragonite-secreting fauna (corals and bivalves) living in tropical seawater have δ11B close to 25‰ that are much higher than calcite-secreting invertebrates such as brachiopods from tropical to high latitudes with δ11B ranging from 16.8‰ to 19.6‰. The first application of this method was to reevaluate the boron isotopic fractionation between calcite and water as a function of pH. We analyzed the calcitic shell of present-day brachiopods living in marine waters (surface down to 450 m) with pH varying from 7.6 to 8.4. By combining our data with those obtained by Sanyal et al. [Paleoceanography 11 (1996) 513] on cultured foraminifera, we derived an isotopic fractionation curve (αcalcite–seawater=0.023X[B(OH)4−]+0.976), resulting in the following relationship between the pH of seawater and the δ11B values of biogenic carbonatesThis equation has a slope equal to that of the experimental clay–water fractionation curve [Palmer et al., 1987, Geochim. Cosmochim. Acta 51 (1987) 2319], which precludes the use of the boron isotope fractionation among calcite–clay pairs as a “paleo-pH meter”.

The necks of the sauropod dinosaurs reached 15 m in length: six times longer than that of the world record giraffe and five times longer than those of all other terrestrial animals. Several anatomical features enabled this extreme elongation, including: absolutely large body size and quadrupedal stance providing a stable platform for a long neck; a small, light head that did not orally process food; cervical vertebrae that were both numerous and individually elongate; an efficient air-sac-based respiratory system; and distinctive cervical architecture. Relevant features of sauropod cervical vertebrae include: pneumatic chambers that enabled the bone to be positioned in a mechanically efficient way within the envelope; and muscular attachments of varying importance to the neural spines, epipophyses and cervical ribs. Other long-necked tetrapods lacked important features of sauropods, preventing the evolution of longer necks: for example, giraffes have relatively small torsos and larg...

The fossil record is our primary window onto the diversification of ancient life, but there are widespread concerns that sampling biases may distort observed palaeodiversity counts. Such concerns have been reinforced by numerous studies that found correlations between measures of sampling intensity and observed diversity. However, correlation does not necessarily mean that sampling controls observed diversity: an alternative view is that both sampling and diversity may be driven by some common factor (e.g. variation in continental flooding driven by sea level). The latter is known as the ‘common cause’ hypothesis. Here, we present quantitative analyses of the relationships between dinosaur diversity, sampling of the dinosaur fossil record, and changes in continental flooding and sea level, providing new insights into terrestrial common cause. Although raw data show significant correlations between continental flooding/sea level and both observed diversity and sampling, these correla...

Sauropodomorph dinosaurs were the dominant terrestrial herbivores of the Late Triassic to Late Jurassic, but the early evolution of herbivory is poorly documented in this clade. In particular, the transition from the relatively simple feeding mechanisms of basal ...

We report new data on 18 dinosaur footprint localities discovered in the Upper Cretaceous of the Gobi Desert of Mongolia, where we have recognized more than 20 000 footprints of dinosaurs. There are at least four types of dinosaur footprints, attributed to theropod, ornithopod, ankylosaurid and sauropod trackmakers. We have also recognized abundant footprints of unidentified trackmakers from each locality. Coexistence of footprints and many skeletal remains in the same and/or nearby beds is a remarkable feature of these Mongolian sites. Analyses of dinosaur footprints and associated body fossil remains for each locality reveal that even in the same beds, the ichnofauna differ from the fauna reconstructed on the basis of body fossils of dinosaurs. The results demonstrate that dinosaur faunal assemblages reconstructed from body fossil or footprint evidence solely should be considered very carefully.

Fossil vertebrates from the Cabao Formation discovered in the area of Nalut in northwestern Libya include the hybodont shark Priohybodus, the crocodilian Sarcosuchus, an abelisaurid, a baryonichine spinosaurid and a large sauropod with spatulate teeth. The Cabao Formation may be Hauterivian to Barremian in age, although an earlier Berriasian to Valanginian age cannot be excluded. Its dinosaur assemblage is reminiscent of that of the El Rhaz and Tiouraren formations of Niger and strongly differs from both the Cenomanian assemblages of Morocco and Egypt and the Late Aptian to Albian fauna of Tunisia. Fossil vertebrates may be an important tool to establish the stratigraphical framework of the poorly dated Early Cretaceous continental deposits of Africa.

ABSTRACT The Abelisauridae are a family of mainly Cretaceous theropod dinosaurs with a wide distribution across the Gondwanan land masses. Although their presence in Europe was reported twenty-five years ago, it has often been considered as controversial largely because of the incompleteness of the available speci-mens. We report here the discovery of well-preserved abelisaurid material, including a highly diagnostic braincase, at a Late Cretaceous (late Campanian) locality in the Aix-en-Provence Basin, near the eponym city in south-eastern France. A new abelisaurid taxon is erected, Arcovenator escotae gen. nov., sp. nov., on the basis of cranial and postcranial material. A phylogenetic analysis reveals that the new Abelisauridae from Provence is more closely related to taxa from India and Madagascar than to South American forms. Moreover, Genusaurus, Tarascosaurus and the previous Late Cretaceous discoveries are identified as basal abelisaurids. Contrary to previously proposed palaeobiogeographical models of abelisaurid evolution, the presence of the new taxon in Europe suggests that Europe and Africa may have played a major role in abelisaurid dispersal, which apparently involved crossing marine barriers.

Recent work in the Campanian Aguja Formation of Big Bend, Texas, has resulted in the recovery of two frontoparietal domes from a new genus of pachycephalosaur. Texacephale langstoni gen. et sp. nov. is diagnosed by a tall, arched nasal boss, flange-like processes articulating the dome with the peripheral elements, and a low pedicel separating the cerebral fossa from the skull roof. The skull dome is composed largely of the fused frontals and parietals, with limited participation of the peripheral elements, and the supratemporal fenestrae remain open. Phylogenetic analysis indicates that Texacephale langstoni is a basal member of the Pachycephalosauria. The discovery of Texacephale supports previous suggestions that the dinosaur fauna of Texas was distinct from that of contemporary assemblages to the north. The phylogenetic analysis presented here indicates that the Asian pachycephalosaurs form a monophyletic group, deeply nested within the Pachycephalosauridae, and that the basal members of the group are all North American. This finding indicates that pachycephalosaurids originated in North America, rather than Asia, as previously believed. The high diversity of North American pachycephalosaurs and the late appearance of pachycephalosaurs in Asia are consistent with this hypothesis. The biology of Texacephale and other Pachycephalosauridae are also discussed. The morphology of the dome in Texacephale and other pachycephalosaurs supports the hypothesis that pachycephalosaurids engaged in intraspecific combat, while the occurrence of Texacephale and other pachycephalosaurs in nearshore deposits argues that the pachycephalosaurs were not restricted to inland habitats.

Abstract We report new data on 18 dinosaur footprint localities discovered in the Upper Cretaceous of the Gobi Desert of Mongolia, where we have recognized more than 20 000 footprints of dinosaurs. There are at least four types of dinosaur footprints, attributed to ...