Skeletal morphology and locomotor adaptation inProlimnocyon atavus, an early Eocene hyaenodontid creodont

Abstract

ABSTRACT Analysis of a recently discovered partial skeleton of Prolimnocyon atavus, an early Eocene creodont (Hyaenodontidae, Limnocyoninae), from the Willwood Formation of the Bighorn Basin, Wyoming, demonstrates that its postcranial skeletal anatomy was most similar to that of extant scansorial procyonid, viverrid, and mustelid Carnivora. Its anatomical traits (including reduced greater tuberosity, prominent and sharp deltopectoral crest, well-developed entepicondyle and brachial flange, ovoid radial head and gently concave, laterally oriented radial notch, moderately deep, laterally compressed ungual phalanges, medially projecting lesser trochanter, flattened talar trochlea with high lateral rim, helical proximal cuboid facet) are commonly associated with joint mobility and abducted limb posture which, in extant mammals, are characteristic of scansorial and ambulatory locomotion. These features resemble those of some early Eocene proviverrine hyaenodontids and, to a lesser extent, miacid Carnivora, but...