All six known specimens of the early hominid Sahelanthropus tchadensis come from Toros-Menalla site 266 (TM 266), a single locality in the Djurab Desert, northern Chad, central Africa. Here we present a preliminary analysis of the palaeontological and palaeoecological context of these finds. The rich fauna from TM 266 includes a significant aquatic component such as fish, crocodiles and amphibious mammals, alongside animals associated with gallery forest and savannah, such as primates, rodents, elephants, equids and bovids. The fauna suggests a biochronological age between 6 and 7 million years. Taken together with the sedimentological evidence, the fauna suggests that S. tchadensis lived close to a lake, but not far from a sandy desert, perhaps the oldest record of desert conditions in the Neogene of northern central Africa.
A new hadrosaurid dinosaur, Arenysaurus ardevoli gen. et sp. nov., from the Late Maastrichtian of Aren (Huesca, South-central Pyrenees) is described on the basis of a partial, articulated skull, mandibular remains and postcranial elements, including vertebrae, girdle and limb bones. Arenysaurus is characterized by having a very prominent frontal dome; nearly vertical prequadratic (squamosal) and jugal (postorbital) processes, and deltopectoral crest of the humerus oriented anteriorly. Moreover, it possesses a unique combination of characters: short frontal (length/width approximately 0.5); midline ridge of parietal at level of the postorbitalsquamosal bar; parietal excluded from the occiput; squamosal low above the cotyloid cavity. A phylogenetical analysis indicates that Arenysaurus is a rather basal member of Lambeosaurinae and the sister-taxon to Amurosaurus and the Corythosaurini-
Six new dinosaurs sites have been found close to the Cretaceous/Tertiary boundary in Arén (south-central Pyrenees, Huesca, Spain) in coastal and non-marine deposits of the Arén and Tremp Formations. The sites contain articulated remains (skull elements, vertebrae, hind-limb bones) and isolated teeth and bones of hadrosaurids, three types of theropod teeth, one sauropod, at least seven types of eggshells (six ornithoid types and one Megaloolithidae probably from a sauropod), remains of other vertebrates, and four charophyte species. The fossil-bearing rocks have been correlated with marine sediments containing planktonic foraminifera from the uppermost Maastrichtian Abathomphalus mayaroensis Biozone. These rich and diversified dinosaur assemblages enable more accurate dating of the faunal changes that took place during the Maastrichtian in Europe and support the hypothesis of a sudden dinosaur extinction at the Cretaceous/Tertiary boundary.
Academic Press
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