Plesiopithecus is an extinct genus of early strepsirrhine primate from the late Eocene. Anatomy Originally described from the right mandible (lower jaw), its confusing anatomy resulted in it being classified as an ape—its name translates "near ape". Plesiopithecus teras, the only species so far identified, was discovered in 1992 by Elwyn L. Simons in Egypt at the base of the Jebel Qatrani Formation at Fayum in quarry L-41. Within two years, a more complete, crushed skull was found, demonstrating that it was a strepsirrhine primate. It is thought to be a close relative of lemuriforms (extant strepsirrhines), and a sister group to either lorisoids or all lemuriforms. Plesiopithecus was a medium-sized strepsirrhine primate, with large orbits, a high muzzle, and a skull exhibiting klinorhynchy (a marked angle between the palate and the basicranium, or the lower region of the braincase). Its large orbits indicate that it was nocturnal, and its teeth suggest that it bored holes in wood in search of soft-bodied insects, just like the aye-aye. Etymology The genus name Plesiopithecus derives from the Greek root plesi- (πλησίος, plēsios), meaning "near", and the Greek word πίθηκος (pithekos), meaning "trickster", which has historically been used to mean "ape". The species name derives from the Greek word τερασ (teras), meaning "wonderful or amazing animal". Evolutionary history Although Plesiopithecus is now clearly recognized as being related to lemuriforms (extant strepsirrhine primates), its phylogenetic relations among the fossil primates are unclear. Phylogenetic analyses using 359 morphological traits place it as a sister group of lemuriforms, along with other Eocene African sister taxa, the djebelemurids, which include Djebelemur and 'Anchomomys' milleri. This Afro-Arabian clade, which includes crown lemuriforms and possibly the disputed azibiids, excludes the Holarctic adapiforms and may be descended from an early Asian branch of adapiforms such as a primitive branch of cercamoniines predating Donrussellia (one of the oldest European adapiforms). A general consensus places Plesiopithecus at the base of the lemuriform clade, possibly closer to the lemuriforms than the djebelemurids. Due to its combination of the lack of a toothcomb (a specialized dental structure found in most lemuriforms) and a front dentition that is enlarged and procumbent, Plesiopithecus has been considered a possible relative of the aye-aye (Daubentonia madagascariensis), suggesting a possible close relationship. This close relationship between Plesiopithecus and the aye-aye within the lemur radiation was recovered by Gunnell et al. (2018), suggesting that lemur evolution involved two dispersal events