Provisional Classification and Key to Living Species of Macaques (Primates: <i>Macac</i><i>a</i>)

TLDR

Nineteen macaque species are divided into four groups—fascicularis, silenus‑sylvanus, sinica, and arctoides—primarily by male genital morphology, with their geographic ranges partly overlapping across groups but largely allopatric within each group. The study provides an artificial key for identifying macaque species based on external morphological characters. The key is constructed from external traits of the recognized species. The key reveals that the silenus‑sylvanus group dispersed earliest, followed by sinica and then fascicularis, and it also highlights shortcomings in Hill’s taxonomic treatment, including classification, key, nomenclature, and range maps.

Abstract

19 recognized species of macaques (Macaca) are allocated to four species groups (fascicularis group, silenus-sylvanus group, sinica group, arctoides group) based primarily on structure of male external genitalia. Geographic ranges of all four species groups are partly sympatric; ranges of species within each group apparently are allopatric. Distribution patterns suggest that the silenus-sylvanus group probably dispersed earliest, the sinica group next, and the fascicularis group most recently; successively more recent dispersals probably contributed to reduction and disjunction of ranges of species groups that dispersed earlier. An artificial key to external characters of recognized species is presented. Deficiencies are noted in Hill's recently published taxonomic treatment of macaques; these criticisms concern Hill's classification, key, nomenclature and range maps.