A new phylogeny of cerapodan dinosaurs

ABSTRACT

This work attempts at providing a revised framework for ornithischian phylogeny, based on an exhaustive data compilation of already published analyses, a critical re-evaluation of osteological characters and an in-depth checking of characters scoring to fix mistakes that have accumulated in previous analyses; we have also included recently described basal ornithischians, marginocephalians and ornithopods. ‘Heterodontosaurids’ are recovered as a paraphyletic group of basal Marginocephalia that progressively lead to the dome-headed ‘true’ pachycephalosaurs. ‘Heterodontosaurids’ consequently fall within Pachycephalosauria sensu Sereno, 1998. The reconfiguration of basal cerapodan relationships pulls the origins of ornithopods to the earliest stages of the Jurassic. Based on the present analysis, we also discuss ornithopod relationships, with a particular focus on basal Iguanodontia. Tenontosaurus is found as the basalmost iguanodontian. The monophyly of Rhabdodontomorpha in a position more derived than Tenontosaurus is supported by the present analysis.

KEYWORDS:

• Phylogeny
• Cerapoda
• Marginocephalia
• Pachycephalosauria
• Ornithopoda
• basal iguanodontia

Acknowledgments

We are grateful to Catherine Forster, Phil Senter, Matthew Herne, Fernando Escaso for their helpful answers to questions concerning material in their care. Special thanks go to Matthew Herne and Fidel Torcida Fernández-Baldor for sharing important photographs and to Miguel Moreno for his invaluable advices on how to proceed with phylogenetic methods. We are particularly grateful to Matt Baron for his careful revision of an earlier version of this paper. More personally, we thank all the people who helped directly or indirectly, and who provided unconditional support, help and accommodation facilities through the long years of data matrix construction and revision (Ferrán and Alba, Cope and Silvia, Fidel, Geoffroy and his family, first author’s family). Financial support has been partially provided by the Spanish Ministerio de Ciencia e Innovación and the European Regional Development Fund (CGL2017-85038-P), by the Agencia Nacional de Promoción Científica y Técnica (PICT 2016-0491), by the Universidad Nacional de Río Negro (PI 40-A-737).

Disclosure statement

No potential conflict of interest was reported by the authors.

Supplementary material

Supplemental data for this article can be accessed here.

Additional information

Funding

This work was supported by the Ministerio de Ciencia e Innovación and the European Regional Development Fund [CGL2017-85038-P]; the Agencia Nacional de Promoción Científica y Técnica [PICT 2016-0491].