Mesomys hispidus
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
Mesomys
Mesomys hispidus

description: 61.
Ferreira’s Spiny Tree-rat
Mesomys hispidus
French: Rat-épineux arboricole / German: Amazonas-Stachelratte / Spanish: Rata arboricola de Ferreira
Other common names: Spiny Tree-rat
Taxonomy. Echimys hispidus Desmarest, 1817,
“Amérique méridionale.” Restricted by G. H. H. Tate in 1939 to “Borba, Rio Madeira, Brazil.”
Mesomys hispidus includes ecaudatus, named byJ. A. Wagner in 1845, ferrugineus named by A. Gunther in 1877, and spicatus named by O. Thomas in 1924. This highly variable and geographically widespread speciesis subdivided into at least six reciprocally monophyletic mtDNA clades that differ in certain morphological attributes. A thorough evaluation of character variation is thus likely to elevate several of these geographical units to species status, some of which may correspond to currently available names now regarded as synonyms, while others will need formal description. Monotypic.
Distribution. Amazon Basin from S & E Colombia, S Venezuela, E Ecuador, E Peru, and N Bolivia, E through Brazil to Rio Tapajos (S of the Amazon River), but to the Atlantic seaboard in Amapa State and the Guianas N ofthis river.
Descriptive notes. Head-body 171-186 mm, tail 160-192 mm; weight up to 160 g. Sizes of Ferreira’s Spiny Tree-rats vary substantially, being smaller in the Guianan part of its distribution (mean headbody 161 mm) and becoming much larger in western Amazonia (head-body 178-186 mm). Otherwise, Ferreira’s Spiny Tree-rat is characterized overall by spiny dorsal fur and long, moderately hairy tail that terminates in short hairy tuft 5-21 mm in length. Upper parts are uniform pale to medium brown, with mid-back often streaked with black. Pelage consists of very conspicuous short, wide, flat, but flexible spines from shoulder to rump, each with pale tip. Eyes are large, and eye shine is moderately bright yellow. Vibrissae are long and fine, reaching posteriorly to shoulders. Tail is robust, uniformly brown, and thinly covered with long, red-brown hairs that do not hide scales. Under parts are uniformly pinkish orange, contrasting sharply with color of sides. Hindfeet are short and broad, each digit has sharp and strongly curved claw, and soles are pink and have large plantar pads. Skulls ofall species of Mesomys are similar to that of the Tuft-tailed Spiny Tree-rat (Lonchothrix emiliae), with short and robust but proportionally narrower rostrum, parallel-sided nasal bones, and low-crowned, rounded cheekteeth with lateral folds that isolate into fossettes with wear. Skull of Ferreira’s Spiny Tree-rat is very similar to that of the Hidden Spiny Tree-rat (M. occultus), except that it has proportionally shorter rostrum and palate, longer and narrower incisive foramina that have an absolutely longer premaxillary septum, and dP*~ M* with more strongly developed fourth fold. Chromosomal complementis 2n = 60 and FN = 116.
Habitat. Submontane and lowland Amazonian rainforests and montane forest on the eastern Andean slopes in Peru, more commonly in upland flooded forest than in the varzea seasonally flooded plain in Rio Jurua region in Brazil, and semideciduous forest in Bolivia, from sea level to elevations of ¢.1000 m. Nearly 97% of all captures atsites along the Rio Jurud were in canopy traps, only 3% were trapped on the ground. Thus, Ferreira’s Spiny Tree-rat is predominantly an arboreal specialist that lives in a variety of forest types, including natural and human-disturbed habitats where some arboreal components remain. It may also be common near fallen logs and in villages close to forests where individuals can be found in house rafters.
Food and Feeding. Stomach contents of Ferreira’s Spiny Tree-rats include insects, plant materials, and fruit pulp. Intestines are proportionally shorter than those of the echimyid bamboo specialists (Dactylomys) or Atlantic Forest herbivores (Phyllomys).
Breeding. Litters of Ferreira’s Spiny Tree-rats have 1-3 young, but most females have single young. Pregnant females were caught throughout the year at localities along the Rio Jurua (Brazil). Male adults consistently had enlarged testes averaging 20 x 9 mm and swollen vesicular glands (18 mm in length); in contrast, testes ofjuveniles maximally measured 10 x 5 mm and vesicular glands were less than 10 mm long.
Activity patterns. Trapping data and direct observations of Ferreira’s Spiny Tree-rats indicate that it is nocturnal.
Movements, Home range and Social organization. There is no information available for this species.
Status and Conservation. Classified as Least Concern on The IUCN Red List. Ferreira’s Spiny Tree-rat occurs in a wide variety of habitats, including human-disturbed landscapes that retain some tree cover, and even in human dwellings. Its distribution also encompasses several large national parks or other protected areas, especially in Ecuador, Peru, Bolivia, and Brazil. Detailed field studies focused on life history, behavior, and other aspects of population ecology are needed. Effort should be directed to delineating species limits within this broadly distributed and highly variable taxon.
Bibliography. Allen (1899a), Cabrera (1961), Desmarest (1817), Eisenberg (1989), Eisenberg & Redford (1999), Emmons (1990, 1997a, 2005), Fischer (1829), Goeldi (1897), Giinther (1877a), Handley (1976), Hice & Velazco (2012), Leal-Mesquita (1991), Orlando et al. (2003), Patton, Pardifas & D'Elia (2015), Patton, da Silva & Malcolm (1994, 2000), Stephens & Traylor (1983), Tate (1935, 1939), Thomas (1924b), Voss et al. (2001), Wagner (1843, 1845), Woods (1993), 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 584, DOI: 10.5281/zenodo.6623649