WELL PRESERVED AUDITORY OSSICLES IN A JUVENILE SPECIMEN OF NIMRAVUS BRACHYOPS

The auditory ossicles are an amplification system that is used by terrestrial vertebrates. The number of ossicles is variable among the vertebrate groups, however the presence of three auditory ossicles (malleus, incus, and stapes) is one of the defining characteristics of the Class Mammalia. There is considerable variability in form across the orders of mammals, and in extant species they can be used to differentiate organisms.

This study reports the presence of well-preserved auditory ossicles in a specimen of juvenile Nimravus brachyops (F:AM 99259) from the White River chronofauna. As the ossicles are preserved in situ, the malleus is the one that can be most easily examined. Based upon the morphology of the muscular process, the lateral process, and the head of the malleus, this specimen most closely resembles the malleus of modern felids and is less like modern pantherines, or other members of the Carnivora. The taxonomic, phylogenetic, and functional implications of this information are still being studied.