Echimys brevicauda Gunther, 1877 Echimyidae Don E. Wilson Thomas E. Lacher, Jr Russell A. Mittermeier 4MQKN Günther 1877 [1962,2364,1606,1652] Mammalia Echimyidae Proechimys Animalia Rodentia 26 578 Chordata species brevicauda    51.    Short-tailed Spiny-rat    French: Rat-épineux a queue courte/ German: Kurzschwanz-Kurzstachelratte/ Spanish: Rata espinosa de cola corta   Other common names: Huallaga Spiny-rat   Taxonomy. Echimys brevicauda Gunther, 1877,   “Chamicuros, Huallaga river,” Loreto, Peru.   Proechimys brevicaudais a member of the longicaudatusspecies group. It includes bolivianus, securus, gularis, and elassopus as synonyms. It is variable in color pattern and karyotype over its known distribution and might require taxonomic revision. Monotypic.    Distribution.W Amazon Basin of S Colombia, E Ecuador, E Peru, NW Bolivia, and W Brazil (Acre and possibly Amazonas states).   Descriptive notes.Head-body 189-253 mm, tail 137-167 mm; weight 240-490 g. The Short-tailed Spiny-rat is moderately sized, with reddish brown overall dorsal color, dark feet, and short (c.65% of head-body length) and weakly bicolored tail. Overall color of head, back, and rump is reddish brown, generally not as dark along midline as in Cuvier’s Spiny-rat ( P. cuvieri). Fulvous lateral stripe characteristically separates darker dorsal pelage from lighter venter, but venter is variously colored in different parts of its distribution, being brownish or grayish in parts of eastern Ecuador (as in the named form gularisby O. Thomas in 1911), reddish buff throughout most of northern and central Peru and western Brazil, and clear white in most individuals from southern Peru and Bolivia. Fulvous lateral stripe continues across ankle to small paler patch at proximal base of metatarsal area on dorsal surfaces of hindfeet. Otherwise, upper surfaces of hindfeet, including all five toes, are uniformly dark. Tail of the Short-tailed Spiny-rat is sparsely haired, much less so and with distinctly shorter hairs than that of Cuvier’s Spiny-rat; scale annuli average 9-10/cm at mid-length. Dorsal pelage is stiff to the touch, but aristiform hairs are less well developed than in Cuvier’s Spiny-rat. Lengths are 18-20 mm, and widths are 0-6—0-8 mm; distinct tapering tips are present on all aristiforms. Cranially, the Short-tailed Spiny-rat is similar to the two other species within the longicaudatusspecies group, being of moderate size with elongated but relatively broad rostrum. Temporal ridge is moderately to weakly developed, often with anterior parietal part separated from posterior lambdoidal part. Incisive foramina are typically strongly lyrate in shape, distally flanged so that anterior palate is deeply grooved with median ridge and complete and keeled septum. Post-orbital process of zygomais nearly obsolete and comprised predominantly byjugal. Mesopterygoid fossa is shallow, generally only barely reaching posterior margins of M?, and wide (angles are 73-80° among geographical specimens). Floor of infraorbital foramen is smooth, lacking groove indicative of infraorbital nerve. Counterfold pattern of cheekteeth is uniformly 3-3-3-3 above and 3(4)—(2)3-(2)3-(2)3 below. In rare individuals, M* and M? may have remnant fourth fold, and southern specimens exhibit higher frequencies of only two folds on M,. Baculum is massive, long (length 7-8-11-7 mm), and wide (proximal width 3:7-5-1 mm; distal width 4-6-5-9 mm), with slight but broad apical wings and expanded base. Rather massive size of baculum make phallusitself long and distinctly heavy or broad in appearance, so much so that palpating phallus in live males 1s an easy way to distinguish the Short-tailed Spiny-rat from sympatric congeners in the field. Chromosomal complementis 2n = 28 and FN = 48 in southern Peru, 2n = 30 and FN = 48 in Ecuador and northern Peru, and 2n = 28 and FN = 48-50 in central Peru and western Brazil.   Habitat.Lowland Amazonian rainforest in non-seasonally flooded forest (terra firma) in primary and disturbed habitats including secondary growth and garden plots at elevations of 200-1800 m. The Short-tailed Spiny-rat also occurs on lowerslopes of the eastern slope of the Andes in Peru and Ecuador.   Food and Feeding.The Short-tailed Spiny-rat is presumably herbivorous, feeding mostly on seeds, fruits, and other plant parts. It consumes commonly grown local garden products, such as yucca and plantains.   Breeding.Breeding of the Short-tailed Spiny-rat appears to commence at the end of the prolonged dry season (November—-December), with reproduction primarily limited to adults of both sexes. In western Brazil, 39% of a sample of 69 females collected in February-March was pregnant; modal litter size was two young (range 1-4). Details as to parity, age at first reproduction, presence of a postpartum estrus, and length of defined breeding season are unavailable.   Activity patterns.The Short-tailed Spiny-rat is easily observed scurrying through leaf litter at night, and all trapping records indicate strictly nocturnal activity pattern.   Movements, Home range and Social organization.Densities of Short-tailed Spiny-rats can reach very high levels, even in highly localized indigenous garden plots, suggesting that tolerance of conspecifics is high and home rangesizes are limited and overlap extensively.   Status and Conservation.Classified as Least Concern on The IUCN Red List. The Shorttailed Spiny-rat is widespread and occurs in multiple forest types, including those highly degraded. It also occurs in protected parks and is unlikely to be declining. Additional studies on distribution, habitat, abundance, ecology, and conservation threats to Short-tailed Spiny-rat are needed.   Bibliography.Allen (1902), Eisenberg & Redford (1999), Emmons (1990, 1997a), Gunther (1877a), Osgood (1944), Patton (1987), Patton & Gardner (1972), Patton & Leite (2015), Patton & Reig (1989), Thomas (19014, 1911b), Woods & Kilpatrick (2005). 3804303307 26 578