A New Basal Neoceratopsian Dinosaur from the Middle Cretaceous of Jilin Province,China

A new basal neoceratopsian dinosaur, Helioceratops brachygnathus gen. et sp. nov., is described from the Quantou Formation （late Early Cretaceous or early Late Cretaceous） in the Liufangzi locality （Jilin province, China）. Helioceratops differs from other basal neoceratopsians with its deep dentary ramus, its steeply-inclined ventral predentary facet, its heterogeneous dentary crowns, and by the denticles and secondary ridges asymmetrically distributed on either side of the primary ridge on its dentary teeth. Along with Auroraceratops and Yamaceratops, Helioceratops represents one of the most derived non-coronosaurian neoceratopsians. The palaeogeographical distribution of basal neoceratopsians appears limited to northern China and southern Mongolia in the current state of our knowledge. It is therefore probable that this region constituted the birthplace for more advanced, Late Cretaceous Coronosanria.

Recent advances on study of hadrosaurid dinosaurs in Heilongjiang(Amur) River area between China and Russia

Four main dinosaur-bearing sites have been investigated in latest Cretaceous deposits from the Amur/Heilongjiang Region ： Jiayin and Wulaga in China （ Yuliangze Formation）, Blagoveschensk and Kundur in Russia （Udurchukan Formation）. More than 90% of the bones discovered in these localities belong to hollow-crested lambeosaurine hadrosaurids： Charonosaurus fiayinensis at Jiayin, Amurosaurus riabinini at Blagoveschensk, Olorotitan arharensis at Kundur, and Sahaliyania elunchunorum at Wulaga. Flat-headed hadrosaurine hadrosaurids are much less numerous, but appear well diversified as well： Kerberosaurus manakini at Blagoveschensk, Wulagasaurus dongi at Wulaga, and a new genus at Kundur. Theropods are represented by shed teeth and isolated bones; isolated scutes and teeth discovered at Kundur are tentatively attributed to nodosaurids. Palynological studies suggest that these sites are probably synchronous with the Lancian＇ vertebrate localities of western North America, which represent the youngest dinosaur faunas in this area. However, the latest Cretaceous dinosaur assemblages are completely different in the Amur/Heilongjiang region （lambeosaurines abundant, ceratopsids absent） and in western North America （ceratopsids abundant, lainbeosaurines extremely rare or absent）. This probably reflects some kind of geographical barrier between both areas by Maastrichtian time rather than strong differences in palaeoecological conditions.