Small-bodied ornithischian dinosaurs from the Middle Jurassic of Sichuan, China

Barrett, P. J. and Butler, R. J. and Knoll, F. (2005) Small-bodied ornithischian dinosaurs from the Middle Jurassic of Sichuan, China. Journal of Vertebrate Paleontology, 25 (4). pp. 823-834. DOI https://doi.org/10.1671/0272-4634(2005)025[0823:SODFTM]2.0.CO;2

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Abstract

Three taxa of small-bodied ornithischian dinosaurs have been described from the Middle Jurassic (Lower Shaximiao Formation: ?Bajocian) locality of Dashanpu, Sichuan Province, People's Republic of China. The taxonomy of these animals (Yandusaurus multidens, Xiaosaurus dashanpensis, and Agilisaurus louderbacki) has become highly confused, with many conflicting opinions regarding the validity of each species and the possible synonymies that might exist between them and other ornithischian taxa from both China and North America. Following re-examination of the relevant material, we propose that all three of the Dashanpu small ornithischians represent valid taxa, each of which can be diagnosed on the basis of at least one autapomorphy. In addition, these taxa can be distinguished from each other by a large number of cranial, dental, and postcranial character states. We demonstrate that "Yandusaurus" multidens is not congeneric with either Y. hongheensis or any other taxon, and therefore propose the new generic name Hexinlusaurus for the reception of the species "Y." multidens. Consideration of the character states present in Hexinlusaurus, Agilisaurus, and Xiaosaurus shows that these taxa are not basal euornithopods ("hypsilophodontids"), as had been suggested by the majority of previous authors, but represent more basal ornithischians. Hexinlusaurus and Agilisaurus can be regarded as Genasauria incertae sedis, whereas Xiaosaurus can only be recognized as Ornithischia incertae sedis on the basis of current data.

Item Type:	Article
Uncontrolled Keywords:	2006 AREP IA48 IA50 2005 P
Subjects:	04 - Palaeobiology
Divisions:	04 - Palaeobiology
Journal or Publication Title:	Journal of Vertebrate Paleontology
Volume:	25
Page Range:	pp. 823-834
Identification Number:	https://doi.org/10.1671/0272-4634(2005)025[0823:SODFTM]2.0.CO;2
Depositing User:	Sarah Humbert
Date Deposited:	19 Oct 2011 15:29
Last Modified:	23 Jul 2013 09:58
URI:	http://eprints.esc.cam.ac.uk/id/eprint/1577

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