Pliopapio, FROST, 2001

FROST, STEPHEN R., 2001, New Early Pliocene Cercopithecidae (Mammalia: Primates) from Aramis, Middle Awash Valley, Ethiopia, American Museum Novitates 3350, pp. 1-36 : 2-3

Pliopapio , new genus

TYPE SPECIES: Pliopapio alemui , new species .

GENERIC DIAGNOSIS: A genus of African papionin, distinguished from Parapapio , Lophocebus , and Cercocebus by the presence of a clear anteorbital drop, although this is not as distinct as in most Papio and Mandrillus . In this aspect, its profile is most similar to that of Macaca , but Pliopapio has a relatively longer muzzle. It is different from Papio (Papio) , Gorgopithecus , Lophocebus , Cercocebus , and Mandrillus in that the muzzle lacks postcanine and suborbital fossae. The absence of maxillary ridges distinguishes it from Papio , Theropithecus (Omopithecus) and Mandrillus . The muzzle dorsum is saddle­shaped and rounded in paracoronal section. In these aspects it is similar to Theropithecus oswaldi (sensu Leakey, 1993, as is used throughout this paper), but is unlike the flattened dorsum and squared paracoronal section found in Papio (including Dinopithecus) and Mandrillus . Relative to neurocranial breadth, the rostrum is narrow in comparison with those of all known African papionins, although it is in the lowest end of variation

for Papio , Mandrillus , and Macaca . Crushing in the anterior portion may contribute to this impression, but cannot account for it entirely.

Unlike those in Parapapio , Cercocebus , and Lophocebus , the cranial vault is separat­ ed from the brow ridges by a distinct ophryonic groove. The temporal lines in the holotype male remain widely separated and do not form a sagittal crest, as opposed to the situation in Theropithecus , Gorgopithecus , Papio (Dinopithecus) , and Paradolichopithecus .

While the mandibular symphysis is shallower and more sloping in profile than that of most papionins, it is shorter and more rounded than that of Parapapio ado (from Laetoli and Kanapoi) or the papionin from Lothagam. In these latter taxa the symphysis is even longer and more sloping, with the incisive alveolar process projecting more anteriorly, producing a more procumbent incisor row. Corpus fossae are absent, distinguishing it from most Papio (Papio) (P. h. kindae females have very slight fossae, and some P. izodi lack them), Gorgopithecus , Theropithecus (Omopithecus) , Mandrillus , and Lophocebus .

The molars are higher crowned, more straight­sided, and less flaring on average than those of Papio , Macaca , Mandrillus , and Lophocebus , and far less so than those of Cercocebus . As in most papionins, but unlike Mandrillus and Cercocebus , the premolars are not particularly large relative to the molars. The mandibular incisors are nearly vertically implanted, whereas those of Parapapio ado from Laetoli and Kanapoi are more procumbent.

ETYMOLOGY: The name refers to the Pliocene age of the taxon and its papionin status.