Cranial Morphology and Anatomy of Two Adult Females of Piliocolobus Gordonorum (udzungwa Red Colobus) (mammalia, Primates: Colobidae)

Taxonomy of the African Red Colobus group is currently unresolved. The single species Procolobus badius has been split into different taxa, but the relationships between the morphotypes are poorly understood, often due to a lack of specimens. One of these taxa, the endangered Piliocolobus gordonorum (Udzungwa Red Colobus) is restricted to the Udzungwa Mountains of southern Tanzania. In this paper, two adult female skulls of P. gordonorum are described comparing morphological features and metrics available from the literature. The two crania are extremely similar, showing very limited differences. The general morphology and metrics show a clear phenotypic affinity to P. badius, with some specific characters (e.g. shape of the occipital foramen, and shape of the mandibular notch) that must be further investigated. Size is only slightly larger than the P. badius mean, and metrics and general anatomy are comparable with this taxon. In contrast, the two skulls display a shorter anterior muzzle and larger neurocranium. Although these data are preliminary and descriptive, they represent a further step in the analysis of this endangered taxon.