The brain of Myotragus balearicus, an insular bovid from the Balearics

Abstract

ABSTRACT Myotragus balearicus is the terminal species of a Caprinae lineage that inhabited the Balearic Islands since the Messinian. Myotragus balearicus had a relatively small brain, reported to be half the size of a contemporary bovid of similar size. This study presents a reassessment of its brain size and anatomy. We demonstrate that the brain of M. balearicus is only 17% smaller when compared to Late Miocene taxa. Since the ancestors of M. balearicus were isolated on the Balearics in the Late Miocene, we deduce that the small brain size of M. balearicus is a feature largely retained from its continental ancestor and only partially the result of geographic isolation. The reduction in brain size can be attributed to reduction of the occipital region. We hypothesise that neuroanatomical changes during the evolutionary process of dwarfism were likely influenced by the absence of ecologically relevant predators.