Maxillae and associated gnathodental specimens of Nacholapithecus kerioi, a large-bodied hominoid from Nachola, northern Kenya

Abstract

The middle Miocene large-bodied hominoid from Nachola, initially attributed to Kenyapithecus, was recently transferred to a new genus and species Nacholapithecus kerioi. The hypodigm of N. kerioi consists of numerous maxillae, mandibles, and isolated teeth, as well as a number of postcranial bones. A detailed description of the previously discovered postcranial material has already been presented. This article aims to give a detailed description of maxillary specimens (including some mandibular fragments associated with them) of N. kerioi collected by the Japan–Kenya Joint Project team during the field seasons of 1982, 1984, and 1986. The maxillary specimens of N. kerioi retain a set of primitive catarrhine features, such as a relatively shallow palate, low position of the anterior zygomatic root, and the lack of enlarged premolars. Yet, compared to the Early Miocene Proconsul, N. kerioi is derived in having a moderately elongated subnasal clivus that appears to have overlapped the hard palate.