Callistomys pictus
Creators: name: Don E. Wilson
name: Thomas E. Lacher, Jr
name: Russell A. Mittermeier
Publisher: name: Lynx Edicions
Year: 2016
Subjects: Biodiversity
Taxonomy
Animalia
Chordata
Mammalia
Rodentia
Echimyidae
Callistomys
Callistomys pictus

description: 29.
Painted Tree-rat
Callistomys pictus
French: Rat-épineux coloré / German: Schwarzweile Baumratte / Spanish: Rata arboricola pintada
Taxonomy. Nelomys pictus Pictet, 1843,
“Bahia.” Restricted by J. Moojen in 1952 to probably from Fazenda Almada in the region north of the city of Ilhéus, Bahia, Brazil.
This species is monotypic.
Distribution. SE Brazil, in coastal Atlantic Forest near [1héus and Itabuna, Bahia State.
Descriptive notes. Head-body 250-295 mm, tail 273-325 mm; weight up to 480 g. The Painted Tree-rat is large, softfurred, and arboreal, with striking black (or brown) and white pelage pattern. Fur is dense and long, with hairs of uneven length. Guard hairs are soft and slender, lacking spines or bristles. Underfur is dense, long, and wavy. Dorsal hairs are brownish at their bases, with black or white tips; black-tipped hairs cover crown of head, shoulders, and dorsum. White-tipped hairs cover neck, shoulders, and flanks. Robusttail is 109-111% of head-body length, densely covered with short black hairs for most of its length but with terminal partsilky white above and golden yellow below. Ears are small and inconspicuous. Forefeet and hindfeet are short, stout, and broad, with elongated toes and stout claws. There are two pairs of lateral mammae. Cranially, jugals are expanded dorso-ventrally; lateral jugal fossa is wide and diffuse anteriorly, not coming to sharp point, with anterior edge offossa positioned above dP*, anteriorto line extending from posterior border of ascending maxillary process of zygomatic arch. Superior zygomatic root of maxillary is expanded posteriorly. Tympanic auditory bullae are inflated, and large auditory meatus is positioned at end of strongly developed auditory tube. Angular process of mandible is strongly projected ventrally with respect to inferior projection of symphysis, such that an angle drawn between ventral posterior tip of angular process and occlusal plane of tooth row, with apex at anterior edge of occlusal surface of P, is greater than 30°. All cheekteeth have three roots; upper and lower cheekteeth are high crowned; P4 and M1 are unilaterally hypsodont (lingual side of crown higher than labial side, crown curved outward); P4-M3 are tetralophodont, with three labial folds and one lingual fold; hypoflexi and mesoflexi are deep, with P4 completely divided byjoined hypoflexus-metaflexus into two, U-shaped lophs, with no mure; M'~* have narrow mure connecting protocone and hypocone. Hypoflexids of dP—M, are set at a strong oblique angle, medial end offlexid extend farther anterior then labial end. Lower premolars are tetralophodont; anteroconid and protoconid united, enclosing anteroexternal flexid as slit-like fossetid; anterior one-half of tooth approximates triangle with its axis slightly tipped anterolabially; and hypoflexids and metaflexids do notjoin (P, is not divided by a continuous flexid). Lower incisorsare robust and strongly curved. Chromosomal complementis 2n = 42 and FN = 76.
Habitat. [Lowland evergreen forest in Atlantic Forest. The Painted Tree-rat can occur in disturbed habitats like cacao plantations.
Food and Feeding. Based on field observations and interviews with local people, the Painted Tree-rat is primarily herbivorous, consuming leaves even from cacao trees in plantations.
Breeding. There is no information available for this species.
Activity patterns. The Painted Tree-rat is primarily arboreal and nocturnal.
Movements, Home range and Social organization. There is no information available for this species.
Status and Conservation. Classified as Endangered on The IUCN Red List. The Painted Treerat has a highly restricted distribution (15,000 km?®) within what is now severely fragmented habitat in Atlantic Forest. It is known from only 13 specimens in museum collections and from the subfossil record of Lagoa Santa, Minas Gerais State, Brazil. Its population has presumably suffered continuous decline. Based on interviews with local people, the Painted Tree-rat was apparently abundant in the past and is now very difficult to locate. Some uncertain records suggest that it may occur in secondary or other highly degraded forest patches. As a rainforest species occurring near human habitation, the Painted Tree-rat has likely been severely affected by deforestation and hunting and is not known to occur in any protected areas. The Painted Tree-rat would clearly benefit from hunting restrictions, habitat restoration, and a captive breeding program with the goal of eventual reintroduction. Additional studies into distribution, habitat, abundance, ecology, and conservation threats to the Painted Tree-rat are needed.
Bibliography. Eisenberg & Redford (1999), Emmons (1990, 1997a, 2005), Emmons & Vucetich (1998), Moojen (1952b), Patton et al. (2015), Pictet (1841, 1843), Tate (1935), Vaz (2002), Ventura et al. (2008), Waterhouse (1848), Woods & Kilpatrick (2005).
description: Published as part of Don E. Wilson, Thomas E. Lacher, Jr & Russell A. Mittermeier, 2016, Echimyidae, pp. 552-604 in Handbook of the Mammals of the World – Volume 6 Lagomorphs and Rodents I, Barcelona :Lynx Edicions on page 566, DOI: 10.5281/zenodo.6623649