Fossils ofCebupithecia were discovered in the "Monkey Beds" of theHonda Group, that has been dated to theLaventan, about 13.5 million years ago.Cebupithecia had a dental formula of 2:1:3:3 on the lower jaw. Theincisors of this species were procumbant, suggesting a close relation toPithecia.[3] and thecanines had a stout appearance. Themolars were flat withcusps having little contours.[2]Cebupithecia had an estimated average body mass around 1,602 g (3.532 lb).[4]Cebupithecia had a relatively longer talar neck and a higher, more squared-shaped talar body. In these features,Cebupithecia is more likecebines oraotins than pitheciines, but its overall pattern is unlike any living platyrrhine group or any of the known fossils.[5]
Cebupithecia also exhibits a relatively large medial protuberance, which is smoothed, another resemblance to aotins. The significance of these characteristics is difficult to interpret.Cebupithecia may be the most primitive known pitheciine, retaining shared primitive resemblances with aotins and cebines. Alternatively, its unusual morphology could reflect a unique, derived (for pitheciines) locomotor pattern. The talar features that distinguishCebupithecia from other pitheciines indicate that leaping was relatively more frequent, as is also indicated by other postcranial features. The locomotor behavior ofCebupithecia has been reconstructed as frequentquadrupedalism and leaping,[5] or more relying on vertical clinging and leaping rather than quadrupedal locomotion, much like members of the extant genusPithecia, to which the genus is related.[2][6]
Later research suggests thatCebupithecia may have employed its tail differently from most nonprehensile-tailed platyrrhines living today, behaviors thatpossibly involved tail-bracing or twisting during hindlimb (pedal grasping) suspensory behaviors. Such behaviors may serve as a preadaptive model for the full-fledged evolution of below-branch tail suspension and prehensility seen in other New World primates.[7]
The evolutionary split betweenPitheciidae, of whichCebupithecia, andCallicebus, includingMiocallicebus, also found in the Honda Group, has been placed at 15.2 million years ago.[8]
