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New hadrosaurid dinosaurs from the uppermost Cretaceous of northeastern China

100%

Godefroit P., Shulin H., Tingxiang Y., Lauters P.

Acta Palaeontologica Polonica

2008

tom 53

nr 1

Several hundred disarticulated dinosaur bones have been recovered from a large quarry at Wulaga (Heilongjiang Province, China), in the Upper Cretaceous (Maastrichtian) Yuliangze Formation. The Wulaga quarry can be regarded as a monodominant bonebed: more than 80% of the bones belong to a new lambeosaurine hadrosaurid, Sahaliyania elunchunorum gen. et sp. nov. This taxon is characterised by long and slender paroccipital processes, a prominent lateral depression on the dorsal surface of the frontal, a quadratojugal notch that is displaced ventrally on the quadrate, and a prepubic blade that is asymmetrically expanded, with an important emphasis to the dorsal side. Phylogenetic analysis shows that Sahaliyania is a derived lambeosaurine that forms a monophyletic group with the corythosaur and parasauroloph clades. Nevertheless, the exact position of Sahaliyania within this clade cannot be resolved on the basis of the available material. Besides Sahaliyania, other isolated bones display a typical hadrosaurine morphology and are referred to Wulagasaurus dongi gen. et sp. nov., a new taxon characterised by the maxilla pierced by a single foramen below the jugal process, a very slender dentary not pierced by foramina, and by the deltopectoral crest (on the humerus) oriented cranially. Phylogenetic analysis indicates that Wulagasaurus is the most basal hadrosaurine known to date. Phylogeographic data suggests that the hadrosaurines, and thus all hadrosaurids, are of Asian origin, which implies a relatively long ghost lineage of approximately 13 million years for basal hadrosaurines in Asia.

Osteology and relationships of Olorotitan arharensis, a hollow−crested hadrosaurid dinosaur from the latest Cretaceous of Far Eastern Russia

88%

Godefroit P., Bolotsky Y. L., Bolotsky I. Y.

Acta Palaeontologica Polonica

2012

tom 57

nr 3

The holotype of Olorotitan arharensis from the Maastrichtian Udurchukan Formation in Kundur, Far Eastern Russia, is the most complete dinosaur discovered in Russia and one of the best preserved lambeosaurines outside western North America. This taxon is diagnosed by following autapomorphies: large helmet−like hollow crest higher than the rest of the skull and extending caudally well beyond the level of the occiput; very high postorbital process of jugal (ratio height of postorbital process/length of jugal = 1); rostral portion of the jugal shorter than in other lambeosaurines, with a perfectly straight rostral margin; very asymmetrical maxilla in lateral view, with ventral margin distinctly downturned; very elongated neck composed of 18 cervical vertebrae; tibia as high as the femur; shorter cnemial crest, about one fifth of tibia length. A phylogenetic analysis, based on 118 cranial, dental, and postcranial characters, indicates that Olorotitan is a member of the Corythosaurini clade, and is the sister taxon of Corythosaurus casuarius, Hypacrosaurus stebingeri, and Hypacrosaurus altispinus. The high diversity and mosaic distribution of Maastrichtian hadrosaurid faunas in the Amur−Heilongjiang region are the result of a complex palaeogeographical history and imply that many independent hadrosaurid lineages dispersed readily between western America and eastern Asia at the end of the Cretaceous.

Ograniczanie wyników

2 Acta Palaeontologica Polonica

2 Godefroit P.

1 Bolotsky I. Y.

1 Bolotsky Y. L.

1 Lauters P.

1 Shulin H.

1 Tingxiang Y.

1 2012

1 2008

Wyniki wyszukiwania

New hadrosaurid dinosaurs from the uppermost Cretaceous of northeastern China

Osteology and relationships of Olorotitan arharensis, a hollow−crested hadrosaurid dinosaur from the latest Cretaceous of Far Eastern Russia