Date of this Version
Chen, K. 2015. Ecology and morphology of the late Miocene musk deer, Longirostromeryx wellsi (Artiodactyla: Moschidae: Blastomerycinae). [M.S. thesis]: Lincoln, University of Nebraska, 145 p.
Longirostromeryx wellsi, one of the latest surviving members of the extinct clade Blastomerycinae (Artiodactyla: Moschidae), possesses highly derived craniodental morphology that deviates from typical musk deer form. Previous work suggests that the unique anatomy of L. wellsi represents adaptations for occupying open savannas. To test this hypothesis I conduct principal components analysis on five postcranial bones of L. wellsi, comparing them to that of several extant ruminant artiodactyls, which are divided among seven habitat categories. These elements are also compared with the postcrania of other blastomerycines. These analyses indicate that L. wellsi anatomy is most similar to that of other blastomerycines, extant musk deer, and artiodactyls that occupy heavy woodland-bushland environments, antithetical to the traditional view that L. wellsi was adapted for open habitats. Slight differences among fossil blastomerycines suggest that early to middle Miocene species were better adapted to densely vegetated habitats than later blastomerycines. Of the late Miocene taxa, Parablastomeryx, typically considered the more primitive form, may have been better suited to open environments than the more derived Longirostromeryx.
The most complete known specimen of Longirostromeryx wellsi, UNSM 125572, is described here. Some features, primarily of the forelimb and proximal hindlimb, show that L. wellsi was not a specialized runner, supporting the closed habitat hypothesis, though other features are indicative of cursorial modification. I propose that these conflicting features represent modification for a unique feeding specialization, appropriate for bushland environments. Overall, this study elaborates the complex ecological story of L. wellsi, including habitat and morphological similarities to other ruminants, with consequences for the evolutionary history of Blastomerycinae as well as paleoenvironmental interpretations of the late Miocene Great Plains.
Advisor: Ross Secord