Mesomys leniceps, Thomas, 1926Mesomys hispidus (Desmarest, 1817)Mesomys stimulax, Thomas, 1911Mesomys occultus Dactylomys dactylinus (Desmarest, 1817)

Don E. Wilson, Thomas E. Lacher, Jr & Russell A. Mittermeier, 2016, Echimyidae, Handbook of the Mammals of the World – Volume 6 Lagomorphs and Rodents I, Barcelona: Lynx Edicions, pp. 552-604 : 584-586

62.

Long-haired Spiny Tree-rat

Mesomys leniceps

French: Rat-épineux du Pérou / German: LanghaarAmazonas-Stachelratte / Spanish: Rata arboricola de pelo largo

Other common names: Peru Spiny Tree-rat, Woolly-headed Spiny Tree-rat

61.

Ferreira’s Spiny Tree-rat

Mesomys hispidus

> ° o

Taxonomy. Mesomys leniceps Thomas, 1926 , “Yambrashbamba, Amazonas, 1830 m,” Peru . Mesomys leniceps may only represent a regional variant of the widespread M. his- pidus. Monotypic.

French: Rat-épineux arboricole / German: Amazonas-Stachelratte / Spanish: Rata arboricola de Ferreira

SE

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.”

= Cod

Distribution. E Andean slopes of N Peru (Amazonas and San Martin regions).

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).

Descriptive notes. Head-body 180 mm, tail 214 mm. No specific data are available for body weight. Long-haired Spiny Tree-rat has brownish and rusty-red dorsal fur

8 {=

623

that is not as spiny as other species of Mesomys . Spines average 20 mm in length, are freely mixed with softer hairs within the fur, and lack distinct pale tips of other species

FAMILY ECHIMYIDAE

Hutias, South American Spiny-rats and Coypu

Plate 37

Species Accounts

of Mesomys . Head of the Long-haired Spiny Tree-rat is hairier than back, slightly “hispid” to the touch. Venter is hairier, rich ocherous overall but with large white patches in axillary and inguinal areas. Forefeet and hindfeet are pale buff above with white digits. Tail is 118% of head-body length and brown along its length; body hair extends farther onto base oftail than in other species (25 mm on average). Tail scales are also smaller, and scalar hairs are more appressed to the shaft. Long tuft of hairs extends distally from tail tip. Skull of the Long-haired Spiny Tree-rat is similar to those of the Tuft-tailed Spiny Tree-rat and other species of Mesomys but differs from the latter in several features, including more slender rostrum, nasals that do not extend behind premaxillary process, incisive foramina that are posteriorly narrowed,jugal and frontal bones around anterior orbital foramina slender such that height of zygoma itself is distinctly narrower, anteroposteriorly divergent molar tooth rows, and cheekteeth that decrease notably in size from dP* to M” Habitat. Known only from upper montane rainforest on the eastern slope of the northern Andes in Peru at elevations of 1554-1980 m.

64.

Para Spiny Tree-rat

Mesomys stimulax

French: Rat-épineux du Para / German: Para-Amazonas-Stachelratte / Spanish: Rata arboricola de Para

Other common names: Central Brazil Spiny Tree-rat, Surinam Spiny Tree-rat

ts.

Taxonomy. Mesomys stimulax Thomas , 1911, “Cameta, Lower Tocantins,” Para, Brazil. Mesomys stimulax was considered a subspecies of a polytypic M. hispidus by earlier authors. It is now recognized as a distinct species. Future studies may associate Rio Tapajos populations with M. hispi- dus; if so, distribution of M. stimulax would be limited to the region between Rio Xin-gu and Rio Tocantins. Monotypic.

= day

.

* if Le

Distribution. E Amazon Basin of Brazil, S

Food and Feeding. There is no specific information available for this species, but the Long-haired Spiny Tree-rat likely has omnivorous to herbivorous habits of its congeners. Breeding. There is no information available for this species.

of the Amazon River, from the Rio Tapajos to the Rio Tocantins in Para State.

Descriptive notes. Head-body 154-196 mm, tail 122-199 mm; weight up to 139 g. The Para Spiny Tree-rat is smaller than most Amazonian populations of Ferreira’s Spiny Tree-rat ( Mesomys hispidus ). It differs from the latter byits buffier and paler overall dorsal pelage and distinct venter with white patches on throat, axilla, chest, and inguinal region; otherwise, belly is fawn colored. Tail is 79-101% of head-body length,is brown along its entire length, and terminates in very short tuft. Ears are short, rounded, and black, surrounded by long hairs. Forefeet and hindfeet are dorsally whitish, without buffy suffusion. Skull of the Para Spiny Tree-rat is small, with smaller proportions compared with western Amazonian populations of Ferreira’s Spiny Tree-rat, from which it can be distinguished by its shorter muzzle, nasal sides mesially parallel and narrower anteriorly rather than broader, and smaller tympanic bullae. Holotype has distinct incisive foramina, with premaxillary part converging anteriorly to narrow, straight-sided point and posterior part narrowing to form shallow grooves on anterior palate. Mesopterygoid fossa is straight-sided rather than bowed outward. Chromosomal complement is identical to that of Ferreira’s Spiny Tree-rat: 2n = 60 and FN = 116.

Activity patterns. There is no information available for this species.

Movements, Home range and Social organization. There is no information available for this species.

Status and Conservation. Classified as Data Deficient on The IUCN Red List. Habitats in vicinity ofthe type locality of the Long-haired Spiny Tree-rat are under strong pressure from human expansion and related logging activities. Additional studies on distribution, habitat, abundance, ecology, and conservation threats to Long Haired Spiny Tree-rat are needed.

Bibliography. Cabrera (1961), Eisenberg & Redford (1999), Ellerman (1940), Emmons (1990, 1997a, 2005), Patton et al. (2015), Tate (1935), Thomas (1926b), Thomas & St. Leger (1926), Upham et al. (2013), Woods (1993), Woods & Kilpatrick (2005).

63.

Hidden Spiny Tree-rat

Mesomys occultus

Habitat. Amazonian rainforest, uniformly in trees of terra firma forests at 4-10 m above the ground from sea level to elevations of ¢.250 m. Food and Feeding. There is no specific information available for this species, but the Para Spiny Tree-rat likely has omnivorous to herbivorous habits of its congeners. 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. There is no information available for this species. Status and Conservation. Classified as Least Concern on The [IUCNRed List. Widespread forest clear-cutting following spread of roads in eastern Amazonia and increased natural fires may be negatively impacting the Para Spiny Tree-rat. Additional studies on distribution, habitat, abundance, ecology, and conservation threats are needed. Bibliography. Cabrera (1961), Emmons (1990, 1997a, 2005), Orlando et al. (2003), Patton et al. (2015), Upham et al. (2013), Voss et al. (2001), Woods (1993), Woods & Kilpatrick (2005).

French: Rat-épineux furtif / German: Blischelschwanz-Amazonas-Stachelratte / Spanish: Rata arboricola oculta

Other common names: Tufted-tailed Spiny Tree-rat

Taxonomy. Mesomys occultus Patton , da Silva & Malcolm, 2000, “Colocacao Vira- Volta, left bank Rio Jurud on Igarapé Ara- bidi, affluent of Parana Breu, Amazonas, Brazil (3°17’S, 66°14°'W).”

= So. art 3 {fs

This species is monotypic.

Distribution. W Amazon Basin of W Brazil, S of the Amazon River, in the lower Jurua and Urucu rivers in Amazonas State.

Descriptive notes. Head-body 167 mm, tail 183 mm. No specific data are available for body weight. The Hidden Spiny Tree-rat is sympatric with Ferreira’s Spiny Tree-rat (M. lispidus) at both known localities, sharing substantial morphological similarity but sharply different karyotypes and deeply divergent mtDNA genomes. It is equivalent to Ferreira’s Spiny Tree-rat in size, color, color pattern, and degree of spine development in dorsal fur, but it differs by its spines on neck and shoulders, with orange mid-bands. Hairs along tail are thin and colorless, and tuft of hairs at tail tip are longer, averaging greater than 30 mm. At base oftail, central pigmented hair of each scale is elongated rather than spine line. Cranially, the Hidden Spiny Treerat is unique in having shorter and wider incisive foramina with shorter premaxillary septum, less conspicuous grooves on anterior palate, and flatter and broader paroccipital processes. Otherwise, skulls of these two sympatric species are exceedingly similar. Four labial folds are present on dP, M', and M?, with the fourth very small and usually lost with wear. M? usually has only three labial folds or, if four, middle two may coalesce into a Y-branched structure. Chromosomal complement is 2n = 42 and FN = 54.

65.

Amazon Bamboo Rat

Dactylomys dactylinus

French: Coro-coro dAmazonie / German: Amazonas-Fingerratte / Spanish: Rata de bambu del Amazonas

Es.Ya akc .. *»

Taxonomy. Echimys dactylinus Desmarest, 1817 , no type locality given. Restricted by O. Thomas in 1912 “upper Amazon Area.” Dactylomys dactylinus includes typus as a synonym. An adequate review of geographical patterning of extensive morphological variation present across the large distribution of D. dactylinus has not been under-taken. Three subspecies recognized, but ranges poorly known and their validity needs to be properly assessed. Subspecies and Distribution.

. theWorld of Mammals the of Handbook

Habitat. Upland Amazonian rainforest. The Hidden Spiny Tree-rat is arboreal and was collected in trees in terra firma forests, at 1-5, 9-6, and 15-4 m above the ground.

Food and Feeding. Diet and foraging habits of the Hidden Spiny Tree-rat are presumably similar to those ofits close relative, Ferreira’s Spiny Tree-rat. These two species are syntopic, living side-by-side in the same local forests; potential competitive interactions involving space use and food overlap warrant detailed study.

~

Breeding. A single pregnant Hidden Spiny Tree-rat, captured in June, had a single embryo with crown—rump length of 35 mm. Actvity patterns. There is no information available for this species.

D.d.dactylinusDesmarest,1817—UpperAmazonofSEColombia,SVenezuela,NEPeru,WBrazil,andNWBolivia,butwithundefinedlimits.

D.d.canescensThomas,1912—LowerAmazonofC&EBrazil.

Movements, Home range and Social organization. There is no information available for this species.

D. d. modestus.onnberg, 1921 — Upper Amazon of E Ecuador.

Descriptive notes. Head—body 315 mm, tail 389 mm; weight up to 325 g. The Amazon Bamboo Rat is large, with relatively soft furred, yellowish to olivaceous, and characterized by distinct pale mid-facial stripe over muzzle and extending posteriorly between eyes and ears onto nape of neck. Stripe contrasts sharply with grizzled yellowish to blackish dorsum, which in turn is streaked with black hairs. Sides become progressively more fulvous, with posterior outer thighs and sides of base oftail bright burnt orange. Ventral color is whitish, with hairs white to bases. Dorsal hairs are black or chestnut at roots, with subterminal black and pale or yellow tips. Head stripe is paler than that of the Bolivian Bamboo Rat ( D. boliviensis ). Long mystacial black vibrissae extend beyond one-half the length of superciliary vibrissae. Apart from its

Status and Conservation. Classified as Least Concern on The IUCN Red List. Little is known about the Hidden Spiny Tree-rat, but one locality of occurrence is adjacent to an oil drilling station. There might be opposing negative (habitat loss or degradation) or positive (minimization of whole-sale forest clear-cutting) forces affecting the Hidden Spiny Tree-rat. No protected areas are included in its distribution. Additional studies on distribution, habitat, abundance, ecology, and conservation threats to the Hidden Spiny Tree-rat are needed.

624

Bibliography. Emmons (2005), Orlando et al. (2003), Patton, Pardinas & D'Elia (2015), Patton, da Silva & Malcolm (2000), Upham et al. (2013), Woods & Kilpatrick (2005).

FAMILY ECHIMYIDAE

Hutias, South American Spiny-rats and Coypu

Plate 37

Species Accounts

basal part (first 60 mm oftail), tail is naked, not bicolored at base, covered with large pentagonal scales (5 annuli/cm), and overall ¢.150% of head-body length. Scale hairs are colorless and short from furred tail base to tip. Forefeet have four digits, with digits two and three distinctly longer and nails instead of claws. Hindfeet have five digits, with reduced hallux. Skull of the Amazon Bamboo Rat is large and has broad and short rostrum, well-developed subtriangular post-orbital processes, and medium-sized bullae. Post-orbital processes of zygomatic arch are mainly composed ofjugal bone. In contrast to the Bolivian Bamboo Rat, paroccipital processes of the Amazon Bamboo Rat are oriented vertically and do not closely follow bullar curvature. There is no nerve canal in infraorbital canal. Palate forms a shelf that extends well behind M?, and upper molar rows diverge antero-posteriorly, with dP* nearly in contact. Chromosomal complement is 2n = 94 and FN = 144.

Habitat. Amazonian lowlands in cane thickets, seasonally inundated (varzea) forests, bamboo stands, and multi-strata tropical evergreen forest from sea level to elevations of ¢.300m. The Amazon Bamboo Rat is found at lower elevations than the Bolivian Bamboo Rat, but they both might co-occur in headwater habitats.

Food and Feeding. Field observations of foraging Amazon Bamboo Rats indicate that they eat bamboo parts.

Breeding. One female Amazon Bamboo Rat was collected on Rio Jurua (Brazil) during the high-water season in June with two embryos, one with crown—rump length of97 mm. Activity patterns. There is no specific information available for this species, but the Amazon Bamboo Rat is nocturnal.

Movements, Home range and Social organization. Vocalizations of Amazon Bamboo Rats recorded along Rio Jurua consisted of series of 5-10 short staccato pulses. In Ecuador, recorded pulses reached a mean of 42, which were produced during 14second calls. Field observations suggest that Amazon Bamboo Rats are social, with family groups foraging together in single bamboo stands.

Status and Conservation. Classified as Least Concern on The IUCN Red List. The Amazon Bamboo Ratis widely distributed and is known to occur in a variety of bamboo and riparian forest habitats. It also occurs in several protected areas.

Bibliography. Allen (1900, 1914b, 1916a), Aniskin (1993), Anthony (1920), Bezerra et al. (2007), Desmarest (1817), Deville (1852), Didier (1962), Dunnum & Salazar-Bravo (2004), Eisenberg & Redford (1999), Emmons (1981, 1984, 1990, 1997a, 2005), Geoffroy Saint-Hilaire (1838b), Jentink (1891), LaVal (1976), Layne (1960), Linares (1998), Lonnberg (1921), Moraes-Santos et al. (1999), Ojasti et al. (1992), Patton, Pardinas & D'Elia (2015), Patton, da Silva & Malcolm (2000), Silva, J.S. & Nunes (2000), da Silva, M.N.F. & Patton (1993, 1998), Thomas (1912b), Woods (1993), Woods & Kilpatrick (2005).

61.

Ferreira’s Spiny Tree-rat

Mesomys hispidus

> ° o

Taxonomy. Mesomys leniceps Thomas, 1926 , “Yambrashbamba, Amazonas, 1830 m,” Peru . Mesomys leniceps may only represent a regional variant of the widespread M. his- pidus. Monotypic.

French: Rat-épineux arboricole / German: Amazonas-Stachelratte / Spanish: Rata arboricola de Ferreira

SE

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.”

= Cod

Distribution. E Andean slopes of N Peru (Amazonas and San Martin regions).

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).

64.

Para Spiny Tree-rat

Mesomys stimulax

French: Rat-épineux du Para / German: Para-Amazonas-Stachelratte / Spanish: Rata arboricola de Para

Other common names: Central Brazil Spiny Tree-rat, Surinam Spiny Tree-rat

ts.

Taxonomy. Mesomys stimulax Thomas , 1911, “Cameta, Lower Tocantins,” Para, Brazil. Mesomys stimulax was considered a subspecies of a polytypic M. hispidus by earlier authors. It is now recognized as a distinct species. Future studies may associate Rio Tapajos populations with M. hispi- dus; if so, distribution of M. stimulax would be limited to the region between Rio Xin-gu and Rio Tocantins. Monotypic.

= day

.

* if Le

Distribution. E Amazon Basin of Brazil, S

Food and Feeding. There is no specific information available for this species, but the Long-haired Spiny Tree-rat likely has omnivorous to herbivorous habits of its congeners. Breeding. There is no information available for this species.

of the Amazon River, from the Rio Tapajos to the Rio Tocantins in Para State.

Descriptive notes. Head-body 154-196 mm, tail 122-199 mm; weight up to 139 g. The Para Spiny Tree-rat is smaller than most Amazonian populations of Ferreira’s Spiny Tree-rat ( Mesomys hispidus ). It differs from the latter byits buffier and paler overall dorsal pelage and distinct venter with white patches on throat, axilla, chest, and inguinal region; otherwise, belly is fawn colored. Tail is 79-101% of head-body length,is brown along its entire length, and terminates in very short tuft. Ears are short, rounded, and black, surrounded by long hairs. Forefeet and hindfeet are dorsally whitish, without buffy suffusion. Skull of the Para Spiny Tree-rat is small, with smaller proportions compared with western Amazonian populations of Ferreira’s Spiny Tree-rat, from which it can be distinguished by its shorter muzzle, nasal sides mesially parallel and narrower anteriorly rather than broader, and smaller tympanic bullae. Holotype has distinct incisive foramina, with premaxillary part converging anteriorly to narrow, straight-sided point and posterior part narrowing to form shallow grooves on anterior palate. Mesopterygoid fossa is straight-sided rather than bowed outward. Chromosomal complement is identical to that of Ferreira’s Spiny Tree-rat: 2n = 60 and FN = 116.

Activity patterns. There is no information available for this species.

Movements, Home range and Social organization. There is no information available for this species.

Status and Conservation. Classified as Data Deficient on The IUCN Red List. Habitats in vicinity ofthe type locality of the Long-haired Spiny Tree-rat are under strong pressure from human expansion and related logging activities. Additional studies on distribution, habitat, abundance, ecology, and conservation threats to Long Haired Spiny Tree-rat are needed.

Bibliography. Cabrera (1961), Eisenberg & Redford (1999), Ellerman (1940), Emmons (1990, 1997a, 2005), Patton et al. (2015), Tate (1935), Thomas (1926b), Thomas & St. Leger (1926), Upham et al. (2013), Woods (1993), Woods & Kilpatrick (2005).

63.

Hidden Spiny Tree-rat

Mesomys occultus

Habitat. Amazonian rainforest, uniformly in trees of terra firma forests at 4-10 m above the ground from sea level to elevations of ¢.250 m. Food and Feeding. There is no specific information available for this species, but the Para Spiny Tree-rat likely has omnivorous to herbivorous habits of its congeners. 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. There is no information available for this species. Status and Conservation. Classified as Least Concern on The [IUCNRed List. Widespread forest clear-cutting following spread of roads in eastern Amazonia and increased natural fires may be negatively impacting the Para Spiny Tree-rat. Additional studies on distribution, habitat, abundance, ecology, and conservation threats are needed. Bibliography. Cabrera (1961), Emmons (1990, 1997a, 2005), Orlando et al. (2003), Patton et al. (2015), Upham et al. (2013), Voss et al. (2001), Woods (1993), Woods & Kilpatrick (2005).

French: Rat-épineux furtif / German: Blischelschwanz-Amazonas-Stachelratte / Spanish: Rata arboricola oculta

Other common names: Tufted-tailed Spiny Tree-rat

Taxonomy. Mesomys occultus Patton , da Silva & Malcolm, 2000, “Colocacao Vira- Volta, left bank Rio Jurud on Igarapé Ara- bidi, affluent of Parana Breu, Amazonas, Brazil (3°17’S, 66°14°'W).”

= So. art 3 {fs

This species is monotypic.

Distribution. W Amazon Basin of W Brazil, S of the Amazon River, in the lower Jurua and Urucu rivers in Amazonas State.

Descriptive notes. Head-body 167 mm, tail 183 mm. No specific data are available for body weight. The Hidden Spiny Tree-rat is sympatric with Ferreira’s Spiny Tree-rat (M. lispidus) at both known localities, sharing substantial morphological similarity but sharply different karyotypes and deeply divergent mtDNA genomes. It is equivalent to Ferreira’s Spiny Tree-rat in size, color, color pattern, and degree of spine development in dorsal fur, but it differs by its spines on neck and shoulders, with orange mid-bands. Hairs along tail are thin and colorless, and tuft of hairs at tail tip are longer, averaging greater than 30 mm. At base oftail, central pigmented hair of each scale is elongated rather than spine line. Cranially, the Hidden Spiny Treerat is unique in having shorter and wider incisive foramina with shorter premaxillary septum, less conspicuous grooves on anterior palate, and flatter and broader paroccipital processes. Otherwise, skulls of these two sympatric species are exceedingly similar. Four labial folds are present on dP, M', and M?, with the fourth very small and usually lost with wear. M? usually has only three labial folds or, if four, middle two may coalesce into a Y-branched structure. Chromosomal complement is 2n = 42 and FN = 54.

65.

Amazon Bamboo Rat

Dactylomys dactylinus

French: Coro-coro dAmazonie / German: Amazonas-Fingerratte / Spanish: Rata de bambu del Amazonas

Es.Ya akc .. *»

Taxonomy. Echimys dactylinus Desmarest, 1817 , no type locality given. Restricted by O. Thomas in 1912 “upper Amazon Area.” Dactylomys dactylinus includes typus as a synonym. An adequate review of geographical patterning of extensive morphological variation present across the large distribution of D. dactylinus has not been under-taken. Three subspecies recognized, but ranges poorly known and their validity needs to be properly assessed. Subspecies and Distribution.

. theWorld of Mammals the of Handbook

Habitat. Upland Amazonian rainforest. The Hidden Spiny Tree-rat is arboreal and was collected in trees in terra firma forests, at 1-5, 9-6, and 15-4 m above the ground.

Food and Feeding. Diet and foraging habits of the Hidden Spiny Tree-rat are presumably similar to those ofits close relative, Ferreira’s Spiny Tree-rat. These two species are syntopic, living side-by-side in the same local forests; potential competitive interactions involving space use and food overlap warrant detailed study.

~

Breeding. A single pregnant Hidden Spiny Tree-rat, captured in June, had a single embryo with crown—rump length of 35 mm. Actvity patterns. There is no information available for this species.

D.d.dactylinusDesmarest,1817—UpperAmazonofSEColombia,SVenezuela,NEPeru,WBrazil,andNWBolivia,butwithundefinedlimits.

D.d.canescensThomas,1912—LowerAmazonofC&EBrazil.

Movements, Home range and Social organization. There is no information available for this species.

D. d. modestus.onnberg, 1921 — Upper Amazon of E Ecuador.

Descriptive notes. Head—body 315 mm, tail 389 mm; weight up to 325 g. The Amazon Bamboo Rat is large, with relatively soft furred, yellowish to olivaceous, and characterized by distinct pale mid-facial stripe over muzzle and extending posteriorly between eyes and ears onto nape of neck. Stripe contrasts sharply with grizzled yellowish to blackish dorsum, which in turn is streaked with black hairs. Sides become progressively more fulvous, with posterior outer thighs and sides of base oftail bright burnt orange. Ventral color is whitish, with hairs white to bases. Dorsal hairs are black or chestnut at roots, with subterminal black and pale or yellow tips. Head stripe is paler than that of the Bolivian Bamboo Rat ( D. boliviensis ). Long mystacial black vibrissae extend beyond one-half the length of superciliary vibrissae. Apart from its

Status and Conservation. Classified as Least Concern on The IUCN Red List. Little is known about the Hidden Spiny Tree-rat, but one locality of occurrence is adjacent to an oil drilling station. There might be opposing negative (habitat loss or degradation) or positive (minimization of whole-sale forest clear-cutting) forces affecting the Hidden Spiny Tree-rat. No protected areas are included in its distribution. Additional studies on distribution, habitat, abundance, ecology, and conservation threats to the Hidden Spiny Tree-rat are needed.

624

Bibliography. Emmons (2005), Orlando et al. (2003), Patton, Pardinas & D'Elia (2015), Patton, da Silva & Malcolm (2000), Upham et al. (2013), Woods & Kilpatrick (2005).

FAMILY ECHIMYIDAE

Hutias, South American Spiny-rats and Coypu

Plate 37

Species Accounts

basal part (first 60 mm oftail), tail is naked, not bicolored at base, covered with large pentagonal scales (5 annuli/cm), and overall ¢.150% of head-body length. Scale hairs are colorless and short from furred tail base to tip. Forefeet have four digits, with digits two and three distinctly longer and nails instead of claws. Hindfeet have five digits, with reduced hallux. Skull of the Amazon Bamboo Rat is large and has broad and short rostrum, well-developed subtriangular post-orbital processes, and medium-sized bullae. Post-orbital processes of zygomatic arch are mainly composed ofjugal bone. In contrast to the Bolivian Bamboo Rat, paroccipital processes of the Amazon Bamboo Rat are oriented vertically and do not closely follow bullar curvature. There is no nerve canal in infraorbital canal. Palate forms a shelf that extends well behind M?, and upper molar rows diverge antero-posteriorly, with dP* nearly in contact. Chromosomal complement is 2n = 94 and FN = 144.

Habitat. Amazonian lowlands in cane thickets, seasonally inundated (varzea) forests, bamboo stands, and multi-strata tropical evergreen forest from sea level to elevations of ¢.300m. The Amazon Bamboo Rat is found at lower elevations than the Bolivian Bamboo Rat, but they both might co-occur in headwater habitats.

Food and Feeding. Field observations of foraging Amazon Bamboo Rats indicate that they eat bamboo parts.

Breeding. One female Amazon Bamboo Rat was collected on Rio Jurua (Brazil) during the high-water season in June with two embryos, one with crown—rump length of97 mm. Activity patterns. There is no specific information available for this species, but the Amazon Bamboo Rat is nocturnal.

Movements, Home range and Social organization. Vocalizations of Amazon Bamboo Rats recorded along Rio Jurua consisted of series of 5-10 short staccato pulses. In Ecuador, recorded pulses reached a mean of 42, which were produced during 14second calls. Field observations suggest that Amazon Bamboo Rats are social, with family groups foraging together in single bamboo stands.

Status and Conservation. Classified as Least Concern on The IUCN Red List. The Amazon Bamboo Ratis widely distributed and is known to occur in a variety of bamboo and riparian forest habitats. It also occurs in several protected areas.

Bibliography. Allen (1900, 1914b, 1916a), Aniskin (1993), Anthony (1920), Bezerra et al. (2007), Desmarest (1817), Deville (1852), Didier (1962), Dunnum & Salazar-Bravo (2004), Eisenberg & Redford (1999), Emmons (1981, 1984, 1990, 1997a, 2005), Geoffroy Saint-Hilaire (1838b), Jentink (1891), LaVal (1976), Layne (1960), Linares (1998), Lonnberg (1921), Moraes-Santos et al. (1999), Ojasti et al. (1992), Patton, Pardinas & D'Elia (2015), Patton, da Silva & Malcolm (2000), Silva, J.S. & Nunes (2000), da Silva, M.N.F. & Patton (1993, 1998), Thomas (1912b), Woods (1993), Woods & Kilpatrick (2005).

63.

Hidden Spiny Tree-rat

Mesomys occultus

Habitat. Amazonian rainforest, uniformly in trees of terra firma forests at 4-10 m above the ground from sea level to elevations of ¢.250 m. Food and Feeding. There is no specific information available for this species, but the Para Spiny Tree-rat likely has omnivorous to herbivorous habits of its congeners. 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. There is no information available for this species. Status and Conservation. Classified as Least Concern on The [IUCNRed List. Widespread forest clear-cutting following spread of roads in eastern Amazonia and increased natural fires may be negatively impacting the Para Spiny Tree-rat. Additional studies on distribution, habitat, abundance, ecology, and conservation threats are needed. Bibliography. Cabrera (1961), Emmons (1990, 1997a, 2005), Orlando et al. (2003), Patton et al. (2015), Upham et al. (2013), Voss et al. (2001), Woods (1993), Woods & Kilpatrick (2005).

French: Rat-épineux furtif / German: Blischelschwanz-Amazonas-Stachelratte / Spanish: Rata arboricola oculta

Other common names: Tufted-tailed Spiny Tree-rat

Taxonomy. Mesomys occultus Patton , da Silva & Malcolm, 2000, “Colocacao Vira- Volta, left bank Rio Jurud on Igarapé Ara- bidi, affluent of Parana Breu, Amazonas, Brazil (3°17’S, 66°14°'W).”

= So. art 3 {fs

This species is monotypic.

Distribution. W Amazon Basin of W Brazil, S of the Amazon River, in the lower Jurua and Urucu rivers in Amazonas State.

Descriptive notes. Head-body 167 mm, tail 183 mm. No specific data are available for body weight. The Hidden Spiny Tree-rat is sympatric with Ferreira’s Spiny Tree-rat (M. lispidus) at both known localities, sharing substantial morphological similarity but sharply different karyotypes and deeply divergent mtDNA genomes. It is equivalent to Ferreira’s Spiny Tree-rat in size, color, color pattern, and degree of spine development in dorsal fur, but it differs by its spines on neck and shoulders, with orange mid-bands. Hairs along tail are thin and colorless, and tuft of hairs at tail tip are longer, averaging greater than 30 mm. At base oftail, central pigmented hair of each scale is elongated rather than spine line. Cranially, the Hidden Spiny Treerat is unique in having shorter and wider incisive foramina with shorter premaxillary septum, less conspicuous grooves on anterior palate, and flatter and broader paroccipital processes. Otherwise, skulls of these two sympatric species are exceedingly similar. Four labial folds are present on dP, M', and M?, with the fourth very small and usually lost with wear. M? usually has only three labial folds or, if four, middle two may coalesce into a Y-branched structure. Chromosomal complement is 2n = 42 and FN = 54.

65.

Amazon Bamboo Rat

Dactylomys dactylinus

French: Coro-coro dAmazonie / German: Amazonas-Fingerratte / Spanish: Rata de bambu del Amazonas

Es.Ya akc .. *»

Taxonomy. Echimys dactylinus Desmarest, 1817 , no type locality given. Restricted by O. Thomas in 1912 “upper Amazon Area.” Dactylomys dactylinus includes typus as a synonym. An adequate review of geographical patterning of extensive morphological variation present across the large distribution of D. dactylinus has not been under-taken. Three subspecies recognized, but ranges poorly known and their validity needs to be properly assessed. Subspecies and Distribution.

. theWorld of Mammals the of Handbook

Habitat. Upland Amazonian rainforest. The Hidden Spiny Tree-rat is arboreal and was collected in trees in terra firma forests, at 1-5, 9-6, and 15-4 m above the ground.

Food and Feeding. Diet and foraging habits of the Hidden Spiny Tree-rat are presumably similar to those ofits close relative, Ferreira’s Spiny Tree-rat. These two species are syntopic, living side-by-side in the same local forests; potential competitive interactions involving space use and food overlap warrant detailed study.

~

Breeding. A single pregnant Hidden Spiny Tree-rat, captured in June, had a single embryo with crown—rump length of 35 mm. Actvity patterns. There is no information available for this species.

D.d.dactylinusDesmarest,1817—UpperAmazonofSEColombia,SVenezuela,NEPeru,WBrazil,andNWBolivia,butwithundefinedlimits.

D.d.canescensThomas,1912—LowerAmazonofC&EBrazil.

Movements, Home range and Social organization. There is no information available for this species.

D. d. modestus.onnberg, 1921 — Upper Amazon of E Ecuador.

Descriptive notes. Head—body 315 mm, tail 389 mm; weight up to 325 g. The Amazon Bamboo Rat is large, with relatively soft furred, yellowish to olivaceous, and characterized by distinct pale mid-facial stripe over muzzle and extending posteriorly between eyes and ears onto nape of neck. Stripe contrasts sharply with grizzled yellowish to blackish dorsum, which in turn is streaked with black hairs. Sides become progressively more fulvous, with posterior outer thighs and sides of base oftail bright burnt orange. Ventral color is whitish, with hairs white to bases. Dorsal hairs are black or chestnut at roots, with subterminal black and pale or yellow tips. Head stripe is paler than that of the Bolivian Bamboo Rat ( D. boliviensis ). Long mystacial black vibrissae extend beyond one-half the length of superciliary vibrissae. Apart from its

Status and Conservation. Classified as Least Concern on The IUCN Red List. Little is known about the Hidden Spiny Tree-rat, but one locality of occurrence is adjacent to an oil drilling station. There might be opposing negative (habitat loss or degradation) or positive (minimization of whole-sale forest clear-cutting) forces affecting the Hidden Spiny Tree-rat. No protected areas are included in its distribution. Additional studies on distribution, habitat, abundance, ecology, and conservation threats to the Hidden Spiny Tree-rat are needed.

624

Bibliography. Emmons (2005), Orlando et al. (2003), Patton, Pardinas & D'Elia (2015), Patton, da Silva & Malcolm (2000), Upham et al. (2013), Woods & Kilpatrick (2005).

FAMILY ECHIMYIDAE

Hutias, South American Spiny-rats and Coypu

Plate 37

Species Accounts

basal part (first 60 mm oftail), tail is naked, not bicolored at base, covered with large pentagonal scales (5 annuli/cm), and overall ¢.150% of head-body length. Scale hairs are colorless and short from furred tail base to tip. Forefeet have four digits, with digits two and three distinctly longer and nails instead of claws. Hindfeet have five digits, with reduced hallux. Skull of the Amazon Bamboo Rat is large and has broad and short rostrum, well-developed subtriangular post-orbital processes, and medium-sized bullae. Post-orbital processes of zygomatic arch are mainly composed ofjugal bone. In contrast to the Bolivian Bamboo Rat, paroccipital processes of the Amazon Bamboo Rat are oriented vertically and do not closely follow bullar curvature. There is no nerve canal in infraorbital canal. Palate forms a shelf that extends well behind M?, and upper molar rows diverge antero-posteriorly, with dP* nearly in contact. Chromosomal complement is 2n = 94 and FN = 144.

Habitat. Amazonian lowlands in cane thickets, seasonally inundated (varzea) forests, bamboo stands, and multi-strata tropical evergreen forest from sea level to elevations of ¢.300m. The Amazon Bamboo Rat is found at lower elevations than the Bolivian Bamboo Rat, but they both might co-occur in headwater habitats.

Food and Feeding. Field observations of foraging Amazon Bamboo Rats indicate that they eat bamboo parts.

Breeding. One female Amazon Bamboo Rat was collected on Rio Jurua (Brazil) during the high-water season in June with two embryos, one with crown—rump length of97 mm. Activity patterns. There is no specific information available for this species, but the Amazon Bamboo Rat is nocturnal.

Movements, Home range and Social organization. Vocalizations of Amazon Bamboo Rats recorded along Rio Jurua consisted of series of 5-10 short staccato pulses. In Ecuador, recorded pulses reached a mean of 42, which were produced during 14second calls. Field observations suggest that Amazon Bamboo Rats are social, with family groups foraging together in single bamboo stands.

Status and Conservation. Classified as Least Concern on The IUCN Red List. The Amazon Bamboo Ratis widely distributed and is known to occur in a variety of bamboo and riparian forest habitats. It also occurs in several protected areas.

Bibliography. Allen (1900, 1914b, 1916a), Aniskin (1993), Anthony (1920), Bezerra et al. (2007), Desmarest (1817), Deville (1852), Didier (1962), Dunnum & Salazar-Bravo (2004), Eisenberg & Redford (1999), Emmons (1981, 1984, 1990, 1997a, 2005), Geoffroy Saint-Hilaire (1838b), Jentink (1891), LaVal (1976), Layne (1960), Linares (1998), Lonnberg (1921), Moraes-Santos et al. (1999), Ojasti et al. (1992), Patton, Pardinas & D'Elia (2015), Patton, da Silva & Malcolm (2000), Silva, J.S. & Nunes (2000), da Silva, M.N.F. & Patton (1993, 1998), Thomas (1912b), Woods (1993), Woods & Kilpatrick (2005).

65.

Amazon Bamboo Rat

Dactylomys dactylinus

French: Coro-coro dAmazonie / German: Amazonas-Fingerratte / Spanish: Rata de bambu del Amazonas

Es.Ya akc .. *»

Taxonomy. Echimys dactylinus Desmarest, 1817 , no type locality given. Restricted by O. Thomas in 1912 “upper Amazon Area.” Dactylomys dactylinus includes typus as a synonym. An adequate review of geographical patterning of extensive morphological variation present across the large distribution of D. dactylinus has not been under-taken. Three subspecies recognized, but ranges poorly known and their validity needs to be properly assessed. Subspecies and Distribution.

. theWorld of Mammals the of Handbook

Habitat. Upland Amazonian rainforest. The Hidden Spiny Tree-rat is arboreal and was collected in trees in terra firma forests, at 1-5, 9-6, and 15-4 m above the ground.

Food and Feeding. Diet and foraging habits of the Hidden Spiny Tree-rat are presumably similar to those ofits close relative, Ferreira’s Spiny Tree-rat. These two species are syntopic, living side-by-side in the same local forests; potential competitive interactions involving space use and food overlap warrant detailed study.

~

Breeding. A single pregnant Hidden Spiny Tree-rat, captured in June, had a single embryo with crown—rump length of 35 mm. Actvity patterns. There is no information available for this species.

D.d.dactylinusDesmarest,1817—UpperAmazonofSEColombia,SVenezuela,NEPeru,WBrazil,andNWBolivia,butwithundefinedlimits.

D.d.canescensThomas,1912—LowerAmazonofC&EBrazil.

Movements, Home range and Social organization. There is no information available for this species.

D. d. modestus.onnberg, 1921 — Upper Amazon of E Ecuador.

Descriptive notes. Head—body 315 mm, tail 389 mm; weight up to 325 g. The Amazon Bamboo Rat is large, with relatively soft furred, yellowish to olivaceous, and characterized by distinct pale mid-facial stripe over muzzle and extending posteriorly between eyes and ears onto nape of neck. Stripe contrasts sharply with grizzled yellowish to blackish dorsum, which in turn is streaked with black hairs. Sides become progressively more fulvous, with posterior outer thighs and sides of base oftail bright burnt orange. Ventral color is whitish, with hairs white to bases. Dorsal hairs are black or chestnut at roots, with subterminal black and pale or yellow tips. Head stripe is paler than that of the Bolivian Bamboo Rat ( D. boliviensis ). Long mystacial black vibrissae extend beyond one-half the length of superciliary vibrissae. Apart from its

Status and Conservation. Classified as Least Concern on The IUCN Red List. Little is known about the Hidden Spiny Tree-rat, but one locality of occurrence is adjacent to an oil drilling station. There might be opposing negative (habitat loss or degradation) or positive (minimization of whole-sale forest clear-cutting) forces affecting the Hidden Spiny Tree-rat. No protected areas are included in its distribution. Additional studies on distribution, habitat, abundance, ecology, and conservation threats to the Hidden Spiny Tree-rat are needed.

624

Bibliography. Emmons (2005), Orlando et al. (2003), Patton, Pardinas & D'Elia (2015), Patton, da Silva & Malcolm (2000), Upham et al. (2013), Woods & Kilpatrick (2005).

FAMILY ECHIMYIDAE

Hutias, South American Spiny-rats and Coypu

Plate 37

Species Accounts

basal part (first 60 mm oftail), tail is naked, not bicolored at base, covered with large pentagonal scales (5 annuli/cm), and overall ¢.150% of head-body length. Scale hairs are colorless and short from furred tail base to tip. Forefeet have four digits, with digits two and three distinctly longer and nails instead of claws. Hindfeet have five digits, with reduced hallux. Skull of the Amazon Bamboo Rat is large and has broad and short rostrum, well-developed subtriangular post-orbital processes, and medium-sized bullae. Post-orbital processes of zygomatic arch are mainly composed ofjugal bone. In contrast to the Bolivian Bamboo Rat, paroccipital processes of the Amazon Bamboo Rat are oriented vertically and do not closely follow bullar curvature. There is no nerve canal in infraorbital canal. Palate forms a shelf that extends well behind M?, and upper molar rows diverge antero-posteriorly, with dP* nearly in contact. Chromosomal complement is 2n = 94 and FN = 144.

Habitat. Amazonian lowlands in cane thickets, seasonally inundated (varzea) forests, bamboo stands, and multi-strata tropical evergreen forest from sea level to elevations of ¢.300m. The Amazon Bamboo Rat is found at lower elevations than the Bolivian Bamboo Rat, but they both might co-occur in headwater habitats.

Food and Feeding. Field observations of foraging Amazon Bamboo Rats indicate that they eat bamboo parts.

Breeding. One female Amazon Bamboo Rat was collected on Rio Jurua (Brazil) during the high-water season in June with two embryos, one with crown—rump length of97 mm. Activity patterns. There is no specific information available for this species, but the Amazon Bamboo Rat is nocturnal.

Movements, Home range and Social organization. Vocalizations of Amazon Bamboo Rats recorded along Rio Jurua consisted of series of 5-10 short staccato pulses. In Ecuador, recorded pulses reached a mean of 42, which were produced during 14second calls. Field observations suggest that Amazon Bamboo Rats are social, with family groups foraging together in single bamboo stands.

Status and Conservation. Classified as Least Concern on The IUCN Red List. The Amazon Bamboo Ratis widely distributed and is known to occur in a variety of bamboo and riparian forest habitats. It also occurs in several protected areas.

Bibliography. Allen (1900, 1914b, 1916a), Aniskin (1993), Anthony (1920), Bezerra et al. (2007), Desmarest (1817), Deville (1852), Didier (1962), Dunnum & Salazar-Bravo (2004), Eisenberg & Redford (1999), Emmons (1981, 1984, 1990, 1997a, 2005), Geoffroy Saint-Hilaire (1838b), Jentink (1891), LaVal (1976), Layne (1960), Linares (1998), Lonnberg (1921), Moraes-Santos et al. (1999), Ojasti et al. (1992), Patton, Pardinas & D'Elia (2015), Patton, da Silva & Malcolm (2000), Silva, J.S. & Nunes (2000), da Silva, M.N.F. & Patton (1993, 1998), Thomas (1912b), Woods (1993), Woods & Kilpatrick (2005).