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First record of a basal neoceratopsian dinosaur from the Late Cretaceous of Kazakhstan

100%

Averianov A., Sues H. D.

Acta Palaeontologica Polonica

2009

tom 54

nr 3

553-556

The oldest known ceratopsians come from the Late Jurassic of China (Zhao et al. 1999; Xu et al. 2006). During the Early Cretaceous, the basal ceratopsian Psittacosaurus was among the most common dinosaurs in Asia but more derived basal neoceratopsians were quite rare on that continent (Xu et al. 2002; Makovicky and Norell 2006). Basal neoceratopsians became more abundant in the Late Cretaceous of Mongolia and China, although they are not known in this region from the latest Cretaceous (You and Dodson 2004; Alifanov 2008). In contrast, basal neoceratopsians are rare during the Early Cretaceous in North America but became common and diverse during the Campanian and Maastrichtian (You and Dodson 2004; Chinnery and Horner 2007). Little is known about the evolutionary history of this group in more inland regions of what are now Kazakhstan and adjoining countries. Asiaceratops documents the presence of basal neoceratopsians in the Cenomanian of Uzbekistan (Nessov et al. 1989). Here we report on the first record of a basal neoceratopsian in the Late Cretaceous of Kazakhstan, based on two cranial bones from the Turonian Zhirkindek Formation in the northeastern Aral Sea region.

Redescription of neoceratopsian dinosaur Archaeoceratops and early evolution of Neoceratopsia

80%

You H., Dodson P.

Acta Palaeontologica Polonica

2003

tom 48

nr 2

Archaeoceratops oshimai Dong and Azuma, 1997 is a basal neoceratopsian from the late Early Cretaceous of Mazongshan area, Gansu Province, northwest China. Here we provide a detailed description on Archaeoceratops oshimai based on both the holotype, which consists of a well preserved, nearly complete skull, partial vertebral column, and partial pelvis, and the paratype, which consists of a partial vertebral column including a nearly complete tail, a partial pelvis, fragmentary hind limb bones, and a complete pes. Cladistic analysis shows that Archaeoceratopsis the sister group to all currently known Late Cretaceous Neoceratopsia, and Late Cretaceous Neoceratopsia diverged into two clades: the Asian Protoceratopsidae and the North American Ceratopsoidea, indicating a dual evolution for the two major groups of horned dinosaurs in two landmasses of Late Cretaceous. A suite of derived features characterizes Ceratopsoidea, such as a round−shaped external naris, a long caudolateral process of the rostral bone, and ventrally curved premaxillary ventral edge.

Ograniczanie wyników

2 Acta Palaeontologica Polonica

1 Averianov A.

1 Dodson P.

1 Sues H. D.

1 You H.

1 2009

1 2003

Wyniki wyszukiwania

First record of a basal neoceratopsian dinosaur from the Late Cretaceous of Kazakhstan

Redescription of neoceratopsian dinosaur Archaeoceratops and early evolution of Neoceratopsia