Proechimys simonsi Thomas 1900
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
Proechimys
Proechimys simonsi

description: 34.
Simons’s Spiny-rat
Proechimys simonsi
French: Rat-épineux de Simons / German: Simons-Kurzstachelratte / Spanish: Rata espinosa de Simons
Other common names: Hendee's Spiny-rat
Taxonomy. Proechimys simonsi Thomas, 1900,
“Perené River, Junin Province, Peru, Altitude 800 m.”
Proechimys simonsi includes hendeei and nigrofulvus as synonyms. Monotypic.
Distribution. E Andean slopes and Amazon Basin of S Colombia, E Ecuador, E Peru, N Bolivia, and W Brazil.
Descriptive notes. Head-body 165-275 mm, tail 118-231 mm; weight 160-400 g. Simons’s Spiny-rat is relatively large, with very characteristic elongated body, long and narrow face, long ears, absolutely and proportionately long tail (¢.85% of headbody length), and long narrow hindfeet.
Tail is sharply bicolored, dark above and white below; it is covered by sparse, fine hair, although small scales are conspicuous to the eye, with 9-13 annuli/cm. Middorsal color is darker than that of sides, reddish brown in tone, coarsely streaked with black hairs, and interspersed by dark brown aristiforms. Aristiform hairs are long (22-24 mm) and thin (0-2-0-4 mm) and terminate in distinctly whip-like tip. Venter, chin, sides of upper lips, and undersides of forelimbs and hindlimbs are pure white, with white of inner legs typically extending across tarsal joints onto hindfeet, which are also usually white above. Simons’s Spiny-rat lacks hypothenar pads on plantar surfaces of hindfeet. Skull is large, rostrum is distinctly long and narrow, and supraorbital ridges are well developed but do not extend onto parietals as temporal ridge. Oval shape of incisive foramina is diagnostic; this shape is occasionally slightly elongated, but posterior margins are never strongly constricted so that flat posterolateral margins lack grooves extending onto anterior palate; premaxillary part of septum is short and rounded and usually no more than one-half the length of opening; and attenuate maxillary part usually is not in contact with premaxillary part. Floor of infraorbital foramen is grooved, with moderately developed lateral flange defining passage of infraorbital branch of maxillary nerve. Anterior border of mesopterygoid fossa is acutely angled (49-53°) and penetrates deeply into posterior palate, reaching anterior one-half of M’ or middle of M?*dP* and M' typically have three folds while M? and M?® have 3-4 folds. Number offolds, particularly on dP,, varies from north to south from four to three, while M -M;typically have three folds, although M, may have only two folds. Counterfold formula is 3-3-3(4)-3(4) /(3)-3-3—(2). Baculum is long (length 8:4-10-1 mm) and narrow (proximal width 1-9-2-5 mm; distal width 1-5-1-9 mm), with rounded and slightly broadened base. Chromosomal complement is 2n = 32 and FN = 56-58 in eastern Ecuador, northern and southern Peru, and western Brazil.
Habitat. Upland, non-seasonally flooded rainforest (terra firma) in the western Amazon Basin and extending into lower montane forest on eastern Andean slopes at elevations of 50-2000 m. Simons’s Spiny-rat occurs in undisturbed primary rainforest and secondary or disturbed forest habitats such as garden plots.
Food and Feeding. There is no information available for this species.
Breeding. In Rio Jurua (W Brazil), pregnant and lactating females were collected throughout most of the year, suggesting continuous breeding. Mean litter size of Simons’s Spiny-rat was two young (range 1-3). Males and females reached sexual maturity after they were fully grown and had molted into their adult pelage. Postpartum estrus was evident in only a few females (simultaneous pregnancy and lactation), and high proportion of adult females (30%) exhibited no prior evidence of mating.
Activity patterns. Trapping data of Simons’s Spiny-rat indicate that it is relatively common, terrestrial, and nocturnal.
Movements, Home range and Social organization. In southern Peru, female Simons’s Spiny-rats seemed to be territorial, which might explain late sexual maturity.
Status and Conservation. Classified as Least Concern on The IUCN Red List. Simons’s Spiny-rat is widespread and common, present in many different forest types across wide elevational distribution, and part of the mammalian fauna in a number of protected parks and indigenous areas. There is no evidence that its numbers are declining. Nevertheless, additional studies on distribution, habitat, abundance, ecology, and conservation threats to Simon’s Spiny-rat are needed.
Bibliography. Cabrera (1961), Eisenberg & Redford (1999), Emmons (1982, 1990, 1997a, 2005), Moojen (1948), Osgood (1944), Patton (1987), Patton & Gardner (1972), Patton & Leite (2015), Patton & Reig (1989), Patton et al. (2000), Thomas (1900b), Thomas & St. Leger (1926), 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 pages 570-571, DOI: 10.5281/zenodo.6623649