Eucritta melanolimnetes from the Early Carboniferous of Scotland, a stem tetrapod showing a mosaic of characteristics

Abstract

The stem tetrapod Eucritta melanolimnetes is described in full from five specimens. The animal is compared in detail with the contemporary and superficially similar temnospondyl Balanerpeton woodi, and with baphetids (=loxommatids). Growth of Eucritta skulls approaches isometry, and lies on the same trajectory as skulls belonging to the genus Baphetes. The function of the temporal embayment is discussed; it was probably not associated with an air-borne hearing device. The axial skeleton of Eucritta was ossified in larger specimens. Ribs in Eucritta gain expanded distal ends with growth, and the animal probably breathed by buccal pumping. An updated cladistic analysis is presented, incorporating data from a fifth specimen. Eucritta remains as a probable basal baphetid, but the sister group to the baphetids remains uncertain.