A new hominoid species from the middle Miocene site of Paşalar, Turkey.

A new species of fossil hominoid is described from the middle Miocene deposits at Paşalar, Turkey. It is the less common of the two Paşalar species discussed by Martin and Andrews (1993), making up approximately 10% of the individuals in the Paşalar hominoid sample according to analyses of the minimum number of individuals. To the diagnostic features of I(1) described by Alpagut et al. (1990) and Martin and Andrews (1993) can now be added further diagnostic features of all the anterior teeth, as well as both upper premolars and P(3). These include discrete, nonmetric features and metric differences at all the noted tooth positions. Attempts to distinguish the upper and lower molars of the two species have so far been unsuccessful, with the possible exception of M(3). The morphology of the new species is similar in most respects to that of Kenyapithecus wickeri from Fort Ternan, especially concerning maxillary morphology. They share robust and moderately deep maxillary alveolar processes, a restricted maxillary sinus with an elevated and uncomplicated floor, lacking the compartmentalization evident to varying degrees in many other taxa, and a zygomatic process that originates and turns laterally fairly high above the alveolar margin. There are also a number of distinctive similarities in the dentition, particularly for I(1), C(1), P(4) and P(3). The I(1) morphology in particular, with greatly hypertrophied lingual marginal ridges bounding a uniformly thickened basal crown area, is distinctive among Miocene hominoids. All of these similarities serve to reinforce the differences noted by others between the derived morphology of K. wickeri and the more primitive morphology of Equatorius africanus from Maboko and Kipsaramon. The new species differs from K. wickeri in morphological details of most of the anterior and premolar teeth that are known for both species, despite the general morphological similarity, and in the size of I(1) versus I(2). One striking feature of the new species is a relatively large incisive fossa, although it cannot be determined if this is associated with an open palatine fenestra, as in many early Miocene hominoids, or a minimally overlapping palate and nasoalveolar clivus, as in some middle and late Miocene hominoids.