Callitrichiade 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 262 346 book chapter 3265 10.5281/zenodo.5730714 4631fcfb-1c02-43ca-add6-eba909339b4a 5730714 8 . Rondon’s Marmoset Mico rondoni French: Ouistiti de Rondon / German: Rondonia-Seidenaffchen / Spanish: Titi de Rondon Taxonomy. Mico rondoni Ferrari et al., 2010 , Cachoeira Samuel (now the Samuel Hydroelectric reservoir) on the Rio Jamari, a right bank tributary of the Rio Madeira, municipality of Candeias do Jamari, Rondonia State , Brazil (08° 45° S, 63° 28° W) . Mico rondoni was first described in 1985 as an isolated population of M. emiliae , which otherwise occurs in southern Mato Grosso State but it is now considered a distinct species. Monotypic. Distribution. Brazilian Amazon,restricted to the Rio Mamoré to the W, Rio Madeira to the N, Rio Ji-Parana to the E, and the Serra dos Pacaas Novos to the S. Descriptive notes. Head-body 20-24 cm, tail 29-5-33 cm; weight 326-9 g (range 250-390 g, n = 6). Rondon’s Marmoset has an overall silvery-pale gray color and blackish hairs on the forehead and sides of the face (lighter and denser closer to the ears and sides of the neck). It has a distinct whitish patch that contrasts with the crown and is restricted to the center of the forehead; blackish crown pelage extends to the back of the head and laterally to the front of the ear. The lower back and proximal parts of the legs are grayish-brown, darkening to almost black at the base ofthe tail, with hairs that are reddish-brown basally, darkening abruptly in the medial band, and then lighter toward the apex. Pelage of the legs darkens gradually to reddish-brown on the shin and blackish on the ankle. Hands and feet are dark. Habitat. Tall evergreen terra firma rainforest in the southern Amazon forest. As is true of all marmosets, Rondon’s Marmosets prefer dense understories, successional forest around tree falls, and areas disturbed by human activities. Food and Feeding. Rondon’s Marmoset eats small fruits, nectar, gums, and small animal prey. It has an enlarged and complex cecum, believed to relate to the consumption of plant exudates (gums). 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. Rondon’s Marmoset is sympatric throughout its range with the slightly smaller Weddell’s Saddle-back Tamarin (Sagu:nus weddelli ). They travel together ¢.40% of the time, with Weddell’s Saddle-back Tamarin moving and foraging at heights of ¢.6 m above the ground, and Rondon’s Marmoset active at higher levels, generally c.11 m above the ground. Fruit parts of their diets undoubtedly overlap, but each has different foraging strategies for small animal prey; Weddell’s Saddle-back Tamarins forage at lower levels in specific sites (e.g. holes and crevices), whereas Rondon’s Marmosets do more foliage gleaning and looking along branches for exposed insects higher up in the lower canopy. A major dietary difference between the two species, however,is the adaptation of Rondon’s Marmoset, and other like species of Mico , to gum feeding by gouging tree trunks, branches, and vines to stimulate gum flow. Weddell’s Saddle-back Tamarins eat the abundant gums exuded from bean pods of the emergent leguminous Parkia pendula and also eat gum from the holes that Rondon’s Marmosets gouge. Rondon’s Marmosets also eat gum from the bean pods. To what extent this interaction may have negative consequences for the marmosets is not known. Status and Conservation. CITES Appendix II. Classified as Vulnerable on The IUCN Red List. Major threats to Rondon’s Marmoset include forest destruction from the major colonization program in Rondonia since 1980s and dam construction. It is rarer than Weddell’s Saddle-back Tamarin and is rare or absent in much of its geographic distribution where there is extensive deforestation, especially along the BR-364 Interstate Highway. This rarity may be because of sympatry and competition with Weddell’s Saddle-back Tamarin. Despite the apparent ability of Rondon’s Marmosets to tolerate habitat disturbance, it may be vulnerable to effects of human colonization, and it may in fact be the most threatened species of Mico . Faunal rescue for the Samuel Hydroelectric Dam on the Rio Jamari resulted in the discovery of Rondon’s Marmoset, and two more dams are being built on the Rio Madeira upriver within its distribution. Bibliography. Ferrari (2004), Ferrari & Martins (1992), Ferrari et al. (2010), Hershkovitz (1977), Lopes & Ferrari (1994), Nagamachi et al. (1996, 1997, 1999), Martins et al. (1987), Nagamachi et al. (1994), Rylands et al. (1993, 2009), Sena et al. (2002), Vivo (1985, 1991).