PithecheirDivision. The name is often attributed to Cuvier 1833 (e.g., Ellerman, 1941; Musser and Carleton, 1993), "which was a vernacular description of ‘Pithecheir melanure’ and has no validity" (Ellerman and Morrison-Scott, 1955:39). Reviewed by Emmons (1993b) in context of describing Bornean Pithecheirops. Pithecheir is an endemic of the Sunda Shelf. Musser and Newcomb (1983) suggested on the basis of cranial and dental traits that Pithecheir is distantly related to Lenothrix, which is supported by molar occlusal patterns (Misonne, 1969) but unsupported by chromosomal data (Yong et al., 1982) and spermatozoal morphology (Breed and Yong, 1986). Chaimanee’s (1998) cladistic analysis of molar traits, however, placed Pithecheir, Lenothrix, and Vandeleuria in the same clade and speculated that it, along with the Palearctic Micromys, may have been the earliest evolutionary cluster to have diverged from the main murine lineage as represented by a Progonomys like ancestor. Ellerman (1949:132) had also indicated a close relationship between Vandeleuria and Pithecheir. Except that it is unquestionably morphologically and phylogenetically most closely related to the Bornean Pithecheirops, alliances to Indomalayan genera other than Lenothrix have yet to be uncovered, and the association of Pithecheir with Lenothrix and Vandeleuria has to be tested by analyses of molecular and additional morphological data. Members of our Pithecheir Division are Sundaic (Lenothrix, Pithecheir and Pithecheirops) or Sulawesian (Eropeplus, Lenomys and Margaretamys) and may prove to be most closely allied to members of the Micromys Division (Micromys, Chiropodomys, Vandeleuria, Haplomys, Vernaya, and Haeromys), which are Palearctic, Indomalayan, and Sulawesian in geographic distributions. Pavlinov et al. (1995a) listed Pithecheir in a Pithecheir Section of a more inclusive Micromys Group.

Present and past distribution and radiation of species in Pithecheir have centered on the Sunda Shelf south of the Isthmus of Kra (10E30' N). In addition to the living species, isolated molars identified as the extinct P. peninsularis were recovered from early and middle Pleistocene cave sediments in peninsular Thailand south of the Isthmus (Chaimanee, 1998).