Geoffroy's Spider Monkey - Taxonomy

Taxonomy

Geoffroy's spider monkey belongs to the New World monkey family Atelidae, which contains the spider monkeys, woolly monkeys, muriquis and howler monkeys. It is a member of the subfamily Atelinae, which includes the spider monkeys, woolly monkeys and muriquis, and of the genus Ateles, which contains all the spider monkeys. The genus name Ateles means "imperfect", a reference to the vestigial thumb. The species name geoffroyi is in honor of French naturalist Étienne Geoffroy Saint-Hilaire.

At least five subspecies of this monkey are recognized:

• Nicaraguan spider monkey, Ateles geoffroyi geoffroyi
• Hooded spider monkey, A. g. grisescens
• Ornate spider monkey, A. g. ornatus
• Mexican spider monkey, A. g. vellerosus
• Yucatan spider monkey, A. g. yucatanensis

Some authorities also recognize A. g. azuerensis and A. g. frontatus as valid subspecies. The black-headed spider monkey, Ateles fusciceps, is considered by authorities such as Groves (1989) and Rylands et al. (2006) to be a separate species from Geoffroy's spider monkey. Other authorities, including Froelich (1991), Collins and Dubach (2001) and Nieves (2005), condider A. fusciceps to be synonymous with A. geoffroyi. Under this treatment, the two subspecies of the black-headed spider monkey represent additional subspecies of Geoffroy's spider monkey, A. g. fusciceps and A. g. rufiventris.

Agreement over the number of spider monkey species is not universal. Kellogg and Goldman (1944) based their classification on fur color, and Groves (1989) based his on fur color and geographic distribution. Kellogg and Goldman differentiated Geoffroy's spider monkey from other species by its dark black head, hands and wrists. Recent studies use mitochondrial DNA to help differentiate species. Such studies by Collins and Daubach (2000, 2001, 2006) indicate the Geoffroy's spider monkey is more closely related to the white-fronted spider monkey, A. belzebuth, and the brown spider monkey, A. hybridus, than it is to the red-faced spider monkey, A. paniscus. According to these studies, A. paniscus branched off from the other spider monkeys approximately 3.27 million years ago and the spider monkeys branched off from the woolly monkeys and muiriquis 3.59 million years ago. Older studies by Porter, et al. indicate the howler monkeys are believed to have branched off from the other Atelides over 10 million years ago.