Pendraig milnerae, a new small-sized coelophysoid theropod from the Late Triassic of Wales

Royal Society Open Science

Stephan N. F. Spiekman¹  Susannah C. R. Maidment¹  Nicholas C. Fraser²  Martín D. Ezcurra³  Richard J. Butler³ 

[1] Department of Earth Sciences, Natural History Museum, Cromwell Road, London SW7 5BD, UK;National Museums Scotland, Chambers Street, Edinburgh EH1 1JF, UK;School of Geography, Earth and Environmental Sciences, University of Birmingham, Edgbaston, Birmingham B15 2TT, UK;

关键词: Pendraig;    Coelophysoidea;    Theropoda;    Triassic;    body size evolution;    osteology;   

DOI  :  10.1098/rsos.210915

来源: DOAJ

【 摘 要 】

We describe a new small-bodied coelophysoid theropod dinosaur, Pendraig milnerae gen. et sp. nov, from the Late Triassic fissure fill deposits of Pant-y-ffynnon in southern Wales. The species is represented by the holotype, consisting of an articulated pelvic girdle, sacrum and posterior dorsal vertebrae, and an associated left femur, and by two referred specimens, comprising an isolated dorsal vertebra and a partial left ischium. Our phylogenetic analysis recovers P. milnerae as a non-coelophysid coelophysoid theropod, representing the first-named unambiguous theropod from the Triassic of the UK. Recently, it has been suggested that Pant-y-ffynnon and other nearby Late Triassic to Early Jurassic fissure fill faunas might have been subjected to insular dwarfism. To test this hypothesis for P. milnerae, we performed an ancestral state reconstruction analysis of body size in early neotheropods. Although our results indicate that a reduced body size is autapomorphic for P. milnerae, some other coelophysoid taxa show a similar size reduction, and there is, therefore, ambiguous evidence to indicate that this species was subjected to dwarfism. Our analyses further indicate that, in contrast with averostran-line neotheropods, which increased in body size during the Triassic, coelophysoids underwent a small body size decrease early in their evolution.

【 授权许可】

Unknown