Kuseracolobus, 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 : 15

Kuseracolobus , new genus

TYPE SPECIES: Kuseracolobus aramisi , new species .

GENERIC DIAGNOSIS: A genus of colobine monkey with a broad interorbital area, as is typical for colobines, but distinguishing it from Libypithecus , Nasalis , and Rhinocolobus (especially considering size). The projection of the lower face anterior to the zygomatic arches in K. aramisi is generally similar, in proportion to overall cranial size, to that of Cercopithecoides , Mesopithecus , Trachypithecus , and the undescribed colobine from Leadu ( NME AL2–34, which is associated with a partial skeleton; see Delson, 1994: 40). In comparison to Colobus , the lower face of K. aramisi is less projecting, and it is distinctly less so than in the longfaced genera Paracolobus , Rhinocolobus , Dolichopithecus , and Nasalis . In profile, the maxillary alveolar margin completely lacks the airorhynchous shape of Semnopithecus .

As is typical for most colobines, the mandibular symphysis lacks a median mental fo­ ramen. This distinguishes the genus from both Rhinocolobus (at least as known from the Shungura and Koobi Fora Formations) and Cercopithecoides , which possess one. In lateral view, the symphysis is deep with a vertical profile. The corpus is quite deep and robust overall and it deepens posteriorly. In its depth and robusticity, the corpus is very different from the Leadu colobine, Procolobus , Cercopithecoides , Semnopithecus , Pygathrix , and Presbytis . It is more like Colobus , Paracolobus , and Rhinocolobus , but is not as deep as the corpora of the last two genera. It is further differentiated from Paracolobus and Rhinocolobus by the presence of larger prominentia laterales, similar to Nasalis (including N. ( Simias )). The gonial region is expanded, separating it from the Leadu colobine, Cercopithecoides , and Procolobus , but far less so than in Paracolobus mutiwa .

In the dentition, the I1 crown does not flare in anterior view, so that the apex is not significantly wider than the base. This is distinct from the flaring I 1 in Procolobus . The P3 protocone is not reduced, as in Cercopithecoides , Colobus , and Rhinocolobus . The distal lophid of the m3 is typically narrower than the mesial, as is typical for the Presbytina and likely primitive for the Colobinae (Szalay and Delson, 1979). Three individuals out of 30 in the K. aramisi sample show hypolophids that are wider than their protolophids, and most are near to even. Most of the m3 hypolophids are wider relative to their protolophids than those of Mesopithecus .

ETYMOLOGY: Named after the Middle Awash locality of Kuseralee Dora (‘‘Place of the Kusera tree’’ in the Afar language).