Alouatta discolor
Creators: name: Russell A. Mittermeier
name: Anthony B. Rylands
name: Don E. Wilson
Publisher: name: Lynx Edicions
Year: 2013
Subjects: Biodiversity
Taxonomy
Animalia
Chordata
Mammalia
Primates
Atelidae
Alouatta
Alouatta discolor

description: 7.
Spix’s Howler
Alouatta discolor
French: Hurleur de Spix / German: Spix-Brullaffe / Spanish: Mono aullador de Spix Other common names: Spix's Red-handed Howler
Taxonomy. Mycetes discolor Spix, 1823,
Forte Curupa (= Gurupa), Para, Brazil.
The type locality is on the southern bank of the Rio Amazonas, not on the island of Gurupa, which is occupied by A. macconnelli. Formerly believed to be a subspecies of A. belzebul. Although C. P. Groves in 2001 considered A. discolor to be a synonym of A. belzebul, R. Gregorin in 2006 concluded it was a distinct species based on the morphology of the cranium and hyoid apparatus and pelage color and patterns. On the left bank of the Rio Santa Helena, it is sympatric with A. seniculus puruensis. Monotypic.
Distribution. Lower Amazonian Brazil S of the Rio Amazonas, from the right bank of the rios Tapajos and Juruena to the rios Xingu and Iriri; its distribution extends E of the Rio Xingu near its mouth to Gurupa I, and S at least as far as the left bank of the Rio Santa Helena (left bank tributary of the Rio Teles Pires in Mato Grosso State), and the Serra do Cachimbo in Para State.
Descriptive notes. Head—body 57-91-5 cm (males) and 46-5-57 cm (females), tail 65— 67-5 cm (males) and 60-5-65 cm (females); weight 6-5-8 kg (males) and 4-8-6-2 kg (females). General color of Spix’s Howler varies from dark brown to black, but a dorsal band, hands, feet, and tip of the tail are rufous-chestnut or mahogany red. The dorsal band is absent or week in young individuals. Spix’s Howlers have distinctly long lateral hairs.
Habitat. Tall terra firma forest, igapo (seasonally flooded forest along clear or black rivers), palm swamps, and secondary forest.
Food and Feeding. The diet of Spix’s Howler was studied by L. Pinto at Paranaita, Rio Santa Helena, Mato Grosso, for one year (1999-2000). The group of 7-9 individuals used 197 individual plants and ate soil from seven arboreal termitaria. Plant food sources comprised 67 species in 24 families; 17 species of Fabaceae accounted for 37% of the feeding records. An additional 17 species were Moraceae, including Ficus (four species), Brosimum, Castilla, Helicostylis, Maquira, and Pseudolmedia, and accounted for 29% of the plant feeding records and 38% of the fruit feeding records. Spix’s Howlers ate flowers, particularly from three species of Bignoniaceae (62% of the records). Ripe fruits were predominant in the diet in all months but one, and their contribution to the diet was similar between wet and dry seasons. Most fruits were available for one or two months. Fruits of Dialium guianense (Fabaceae) were eaten for six months, and they provided 26% of the fruit part of the diet and 15-5% of the overall diet. Fruits of this species were abundant in the dry season and made up most of the diet at that time. Young and mature leaves of Acacia ct. polyphylla were eaten in every month, contributing 0-4-21-2% to the monthly diet. The annual diet was 55% ripe fruit and some unripe fruit (0-6%), 19-8% young leaves, 5-7% flowers, 5% mature leaves, 4-4% bark, 3-2% decaying wood, 2:3% live wood, 0-5% soil from termitaria, and small amounts of twigs, petioles, and orchid pseudobulbs. Compared with the diets of other howlers, Spix’s Howler has one of the highest rates of frugivory.
Breeding. L. Pinto observed copulations of Spix’s Howlers with an average duration of 40 seconds, preceded by the male offering to groom the female. She reported three births in April, August, and September 2000. One of births occurred in a tall tree with its canopy covered with vines.
Activity patterns. In the study at Paranaita, the daily activity budget over the year was 587% resting, 20% feeding, 14-2% traveling, 4% moving around in trees, and 3-1% engaged in social interactions and other activities. Spix’s Howlers tend to retire to their sleeping trees earlier in the wet season. Most sleeping trees had a canopy covered with tangles of vines, where the individuals could be well hidden.
Movements, Home range and Social organization. Groups of Spix’s Howlers are unimale-multifemale or multimale-multifemale, with 2-9 individuals. The group of 7-9 individuals studied in Paranaita initially had an adult male, two adult females, one subadult male, one subadult female, and two female infants. In the course of 13 months, in addition to changes in ages of some members, three infants were born and the subadult male emigrated. The home range of this group was 69 ha, mostly in terra firma forest but also including areas of Euterpe palm swamp and igapo. Seasonal migration was observed during peak fruiting in igapo during the flood season (January—April). Daily movements of this group were 176-1425 m, with an average of 761 m/day throughout the year and with no seasonal variation.
Status and Conservation. CITES Appendix II. Classified as Vulnerable on The IUCN Red List. There is only one study of the Spix’s Howler in the wild. Hunting and deforestation are occurring throughoutits distribution, and it is particularly threatened by the advancing agricultural frontier along the Santarém-Cuiaba Highway, where the land is logged, deforested, and turned into cattle ranches and industrial plantations (e.g. soy bean). Tapajos, Itaituba I, Itaituba II, and Altamira national forests are within its distribution, but they are notstrictly protected.
Bibliography. Auricchio (1995), Bonvicino et al. (1989), Gregorin (2006), Gregorin et al. (2008), Groves (2001), Langguth et al. (1987), Pinto (2002), Pinto & Setz (2000, 2003, 2004).
description: Published as part of Russell A. Mittermeier, Anthony B. Rylands & Don E. Wilson, 2013, Atelidae, pp. 484-549 in Handbook of the Mammals of the World – Volume 3 Primates, Barcelona :Lynx Edicions on page 528, DOI: 10.5281/zenodo.5727205