Phitheciidae Author Russell A. Mittermeier Author Anthony B. Rylands Author Don E. Wilson text 2013 2013-03-31 Lynx Edicions Barcelona Handbook of the Mammals of the World – Volume 3 Primates 432 483 book chapter 69154 10.5281/zenodo.6632289 4420304b-d31c-468a-a431-2145caa8e2c0 978-84-96553-89-7 6632289 36. Equatorial Saki Pithecia aequatorialis French: Saki d’Equateur / German: Aquatorialsaki / Spanish: Saki ecuatoriano Taxonomy. Pithecia aequatorialis Hershkovitz, 1987 , Santa Luisa, lower Rio Nanay, Loreto department, Peru. Altitude ¢.160 m. The taxonomy of Pithecia followed hereis that proposed by Hershkovitz in 1987. A taxonomic revision currently being undertaken by L. K. Marsh will provide a broader and more accurate understanding of the diversity and distributions of the sakis. Monotypic. Distribution. E Ecuador and N Peru, S of the lower Rio Napo and the Rio Curaray (a right bank affluent of the Napo), W as far the Rio Tigre and its right bank affluent the Rio Corrientes, and E to the Rio Amazonas. Current understanding of the distribution of P. aequatorialis , following the 1987 review of P. Hershkovitz, has it extending NW to the Andes in Ecuador, but an ongoing revision of the systematics of this genus indicates that this is not the case, and the distribution is undoubtedly smaller and possibly restricted to Peru. Descriptive notes. Head-body 39.4-44 cm (males, n = 2) and 39.2-40.5 cm (females, n = 4), tail 45-47.4 cm (males, n = 2) and 44.8-44.9 cm (females, n = 4); weights unknown but probably similar to that of other Amazonian species at ¢.3 kg. Male and female Equatorial Sakis are dichromatic. They have distinctive long, shaggy black hairs, with stippled white throughout, and thick tails. Distinct among sakis, male Equatorial Sakis have a characteristic white horseshoe circling their faces, with very bright orange and extensive ruffs. Females are grayish but have loose white shaggy faces, which distinguishes them from females of other species of sakis, and buffy to light orange ruffs. Both sexes of Equatorial Sakis have white hands and feet. Males are slightly larger than females. Habitat. [.owland Amazonian terra firma rainforest and seasonally flooded white-water forest (varzea). Food and Feeding. There is no information available for this species. Breeding. There is no information available for this species. Activity patterns. There is no information available for this species. Movements, Home range and Social organization. Mean group sizes of Equatorial Sakis have been recorded at 3-4-3-6 individuals, with 2-8 individuals, mostly containing a single adult pair, but groups sometimes also contain supernumerary adults of either sex. Population surveys in a number of localities in Peru resulted in density estimates of 7-8 ind/ km? near Rio Itaya, 5-6 ind/km® near Rio Tigre, and 5-9 ind/km” near Rio Curaray. Status and Conservation. CITES Appendix II. Classified as Least Concern on The [UCN Red List. The Equatorial Saki has a large geographic distribution. Population surveys indicate that it is quite common, and there is no reason to believe it is threatened. Bibliography. Anderson (1997), Aquino & Encarnacion (1994b), Aquino et al. (2009), Hershkovitz (1979b, 1987a), Heymann, Encarnacion & Canaquin (2002), Johns (1991), de Luna et al. (2010), Marsh (2006), Marsh & Veiga (2008b), Norconk (2011), Norconk & Setz (2013), Tirira (2007).