AUTHOR=Mann Arjan , Dudgeon Thomas W. , Henrici Amy C. , Berman David S , Pierce Stephanie E. 

TITLE=Digit and Ungual Morphology Suggest Adaptations for Scansoriality in the Late Carboniferous Eureptile Anthracodromeus longipes

JOURNAL=Frontiers in Earth Science

VOLUME=9

YEAR=2021

URL=https://www.frontiersin.org/journals/earth-science/articles/10.3389/feart.2021.675337

DOI=10.3389/feart.2021.675337

ISSN=2296-6463

ABSTRACT=<p>A new skeleton of the exceedingly rare, late Carboniferous eureptile <italic>Anthracodromeus longipes</italic> (<xref ref-type="bibr" rid="B4">Carroll and Baird, 1972</xref>), reveals the presence of a reduced phalangeal count in the manus and pedes and uniquely recurved unguals. With these data, we quantitatively evaluate the locomotor ecology of <italic>Anthracodromeus</italic> using morphometric analyses of the phalangeal proportions, ungual curvature, and ungual shape. Our findings indicate that the anatomy of <italic>Anthracodromeus</italic> likely facilitated scansorial clinging to some degree <italic>via</italic> distally recurved unguals and increased surface area of the large manus and pes. This suggests that <italic>Anthracodromeus</italic> was among the earliest amniotes to show climbing abilities, pushing back the origins of scansoriality by at least 17 million years. It further suggests that scansoriality arose soon after the origin of amniotes, allowing them to exploit a wide range of novel terrestrial niches.</p>