|Scientific Name:||Ateles marginatus (É. Geoffroy, 1809)|
Ateles belzebuth ssp. marginatus (É. Geoffroy, 1809)
|Taxonomic Notes:||The taxonomy of the spider monkeys is based on Kellogg and Goldman (1944) and Hill (1962). The forms hybridus, chamek and marginatus are listed as distinct species and A. fusciceps robustus Allen, 1914 is considered a junior synonym of A. f. rufiventris Sclater, 1871 following Heltne and Kunkel (1975) (see Rylands et al. 2000).
Froehlich et al. (1991), and Medeiros (1994; Medeiros et al. 1997) argued that A. paniscus is a distinct form with no subspecies. De Boer and Bruijn (1990) indicated that chamek should be considered a full species, and likewise Sampaio et al. (1993) argued that the forms paniscus and chamek should be considered distinct species on the basis of the genetic distance between them. Ateles chamek was found to be closer to belzebuth than to paniscus (see also Nieves et al. 2005).
M.G.M. van Roosmalen reported (5 August 2003) an undescribed species of spider monkey within the supposed range of A. marginatus. It "occurs in the most south-eastern limit of the genus' distribution and inhabits the dry savanna forests and cerradão of northern Mato Grosso. Its western limit is the Rio Teles Pires and eastern limit is the Rio Culuene, a headwater tributary of the Rio Xingú. Its distribution is disjunct with that of Ateles marginatus along the lower and middle Rio Xingú, Pará, west as far as the Rio Tapajós and east as far as the left bank of the lower Rio Tocantins." It differs from A. marginatus by "the dark chestnut brown black fur, the pink instead of pitch-black muzzle and circumocular rings, and larger white whiskers and triangular blaze." According to van Roosmalen, it can be seen along the headwater effluents of the Rio Xingú, such as the Rios Culuene, Curisevo, Batoví, Ronuro, and Von den Steinen.
|Red List Category & Criteria:||Endangered A2cd+3cd ver 3.1|
|Assessor(s):||Mittermeier, R.A., Boubli, J.-P. & Di Fiore, A.|
|Reviewer(s):||Mittermeier, R.A. & Rylands, A.B. (Primate Red List Authority)|
Listed as Endangered as there is reason to believe the species has declined by at least 50% over the past 45 years (three generations) due primarily to hunting and habitat loss. Over the coming 45 years, this decline is likely to reach similar proportions due to expanding soy bean agriculture.
|Previously published Red List assessments:|
|Range Description:||Ateles marginatus is endemic to the Brazilian Amazon, occurring between the Rio Tapajós (right bank) and its tributary, the Rio Teles Pires (right bank) and the Rio Xingu (left bank), south of the Rio Amazonas (Kellogg and Goldman 1944; Ravetta 2005). This is the least known of the Amazonian spider monkeys.|
Native:Brazil (Mato Grosso, Pará)
|Range Map:||Click here to open the map viewer and explore range.|
|Population:||There are no published population densities available.|
|Current Population Trend:||Decreasing|
|Habitat and Ecology:||Occurs in primary lowland rain forest.|
Spider monkeys travel and forage in the upper levels of the forest. They spend much time in the canopy and also use the middle and lower strata but are rarely seen in the understorey. In accordance with their use of the highest levels of the forest, they are highly suspensory. When travelling they spend more time hanging from branches, moving by brachiation and arm swinging, and climbing than they do walking or running on all fours. They are highly frugivorous and feed largely on the mature, soft parts of a very wide variety of fruits, which comprise 83% of their diet and are found mainly in the emergent trees and upper part of the forest canopy (Van Roosmalen and Klein 1988). They also eat young leaves and flowers (both especially at times of fruit shortage during the beginning of the dry season), and besides such as young seeds, floral buds, pseudobulbs, aerial roots, bark, decaying wood, and honey, and very occasionally small insects such as termites and caterpillars. They play a significant role as seed dispersers. Van Roosmalen (1985; Van Roosmalen and Klein 1988) found that A. paniscus was dispersing the seeds of at least 138 species (93.5% of all fruits species used) through their ingestion and subsequent defecation (endozoochory). A further 10 species were being dispersed by the monkeys carrying them off some distance from the tree before dropping them (exozoochory). In only 23 species were the seeds being ruined or eaten (seed predation).
Spider monkeys live in groups of up to 20-30 individuals (for review see Van Roosmalen and Klein 1988). However, they are very rarely all seen together, and nearly always to be found travelling, feeding and resting small in groups of varying size and composition (most usually 2-4), the only persistent association being that of a mother and her offspring (McFarland Symington 1990). Group members will also travel on their own. Each female in the group has a “core area” of the group’s home range which she uses most. Ateles are rarely seen in association with other primates and mostly they are occasional and ephemeral, resulting from the simultaneous occupation of fruiting trees.
Spider monkeys apparently reach sexual maturity at 4-5 years of age (Klein 1971; Eisenberg 1973, 1976). They give birth to single offspring after a long gestation period of 226-232 days, with a minimum theoretical interbirth interval in captivity of 17.5 months, but in the wild probably as long as 28-30 months (Eisenberg 1973, 1976). Late maturation and long inter-birth intervals make it difficult for them to recover from hunting and other threats.
|Major Threat(s):||Although it occurs south as far as the north of the state of Mato Grosso, its range is relatively small, cut by major highways such as the Transamazon and the Cuiabá-Santarém, and in many parts subject to active and widespread deforestation (especially in the south), and, as in all spider monkeys, A. marginatus is particularly susceptible to hunting. Accelerated expansion of the agricultural frontier in northern Mato Grosso, with the ongoing establishment of enormous areas of soy bean plantations accompanying the paving of the Cuiabá-Santarém highway are additional and major threats.|
This species occurs in a number of national forests in Brazil, including Tapajós National Forest (545,000 ha), Xingu National Forest (252,790 ha), Alatmira National Forest (689,012 ha), Itaituba I National Forest (220,034 ha), and Itaituba II National Forest (440,500 ha). More strictly protected areas are needed for the conservation of this species.
Surveys are currently ongoing throughout the range of the species (Ravetta 2005; A. L. Ravetta pers. comm.).
It is listed on Appendix II of CITES.
|Citation:||Mittermeier, R.A., Boubli, J.-P. & Di Fiore, A. 2008. Ateles marginatus. The IUCN Red List of Threatened Species 2008: e.T2282A9390334.Downloaded on 22 February 2018.|