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Article: A redescription of Orovenator mayorum (Sauropsida, Diapsida) using high‐resolution μCT, and the consequences for early amniote phylogeny

Papers in Palaeontology - Volume 5 Issue 2 - Cover
Publication: Palaeontology
Volume: 5
Part: 2
Publication Date: May 2019
Page(s): 197 239
Author(s): David P. Ford, and Roger B. J. Benson
DOI: 10.1002/spp2.1236
Addition Information

How to Cite

FORD, D.P., BENSON, R.B.J. 2019. A redescription of Orovenator mayorum (Sauropsida, Diapsida) using high‐resolution μCT, and the consequences for early amniote phylogeny . Papers in Palaeontology, 5, 2, 197-239. DOI: /doi/10.1002/spp2.1236

Author Information

  • David P. Ford - Department of Earth Sciences University of Oxford South Parks Road Oxford OX1 3AN UK
  • Roger B. J. Benson - Department of Earth Sciences University of Oxford South Parks Road Oxford OX1 3AN UK

Publication History

  • Issue published online: 03 May 2019
  • Manuscript Accepted: 11 June 2018
  • Manuscript Received: 01 February 2018

Funded By

NERC. Grant Number: NE/L0021612/1

Online Version Hosted By

Wiley Online Library
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Abstract

The earliest known neodiapsid Orovenator mayorum from the lower Permian of Oklahoma is redescribed using high‐resolution μCT, revealing remarkable details of the skull anatomy. Our findings are relevant to both palaeoecology (suggesting burrowing and nocturnality) and phylogeny. Orovenator and other sauropsids share at least 16 character states with varanopids, many of which were not recognized by previous studies. These include a rounded subnarial shelf of the premaxilla, a posterodorsal extension of the external naris, the asymmetrical bifurcation of the anterior vomer, and a prominent dorsomedial shelf of the surangular. This exceptional degree of similarity between Orovenator and varanopids (a nominally synapsid clade) questions our current understanding of relationships among early amniotes. We test this by including Orovenator in a phylogenetic data matrix used in an earlier study to differentiate between early diapsids and synapsids, and find a monophyletic clade of Orovenator + varanopids within Diapsida. Recent phylogenetic research on early amniote evolution has focused on resolving intra‐clade affiliations rather than the interrelationships of major taxonomic groups. Nevertheless, the relative incompleteness of existing phylogenetic character lists for early amniotes can only be remedied by detailed cross‐clade assessment. We therefore suggest that early amniote relationships require further scrutiny before we can confidently accept or reject our new phylogenetic hypothesis.

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