Abstract
Observations on specimens of Ateles paniscus paniscus, A. p. chamek and Ateles fusciceps rufiventris (= A. f. robustus) reveal unreported variations in coat color and lead to expansions of the current taxonomic descriptions of these subspecies. These variants are significant for the correct identification of spider monkeys used in biomedical research and in terms of distribution and spéciation within the genus Ateles.