Ichthyomys stolzmanni, Thomas, 1893

Don E. Wilson, Russell A. Mittermeier & Thomas E. Lacher, Jr, 2017, Cricetidae, Handbook of the Mammals of the World – Volume 7 Rodents II, Barcelona: Lynx Edicions, pp. 204-535 : 407

348.

Stolzmann’s Crab-eating Rat

Ichthyomys stolzmanni

French: Ichthyomys de Stolzmann / German: Stolzmann-Krabbenratte / Spanish: Rata cangrejera de Stolzmann

Other common names: Stolzmann's Ichthyomys

Taxonomy. Ichthyomys stolzmanni: Thomas, 1893 , “Chanchamayo,” near Tarma, Junin, Peru.

Ichthyomys stolzmanni 1s the type species of the genus. Traditionally, population in Ecuador was considered a subspecies, orientalis , that differs from typical Peruvian form based on metacarpal color. Nevertheless, the specimen collected at the Jurumbuno River in Ecuador had bicolored tail to its medial part, while posterior one-half was uniformly dark (not previously recorded in Ichthyomys ). Additional specimens should be collected to fill the gap of nearly 1000 km between Ecuadorean and Peruvian localities and allow assessment of within and between population variation in tail color. Monotypic.

Distribution. Known from only three localities in E Andean piedmont of Ecuador and four localities in Peru.

Descriptive notes. Head—body 160 mm,tail 177-185, ear 9-11 mm, hindfoot 38-41 mm; weight 140 g. Stolzmann’s Crab-eating Ratis a large-bodied lowland species, with large hindfeet, sharply bicolored tails, bilobed M,, and narrow skulls. Dorsum is dark brown; venter is whitish, with yellowish shades; pectoral region has dark brown strip; and thick short mystacial whiskers do not surpass shoulder when bent backward. Tail is longer than head-body length, thick, robust, and densely covered with hair, dark brown dorsally and whitish ventrally. Metacarpal region is whitish, with long dark brown hair. Palmar surface has five pads: thenar and hypothenar pads are enlarged and separated by a small space, and the three interdigital pads are of similar size, c.50% of the thenar pad size.

Habitat. Primary and second forests at elevations of 900-1700 m in Ecuador and 2800-3400 m in Peru.

Food and Feeding. Stolzmann’s Crab-eating Rat eats crabs, shrimp, isopods, other aquatic invertebrates such as insect larvae, and occasionally small vertebrates.

Breeding. No information.

Activity patterns. Stolzmann’s Crab-eating Rat is both diurnal and nocturnal.

Movements, Home range and Social organization. Stolzmann’s Crab-eating Rats are solitary.

Status and Conservation. Classified as Data Deficient on The IUCN Red List. Although Stolzmann’s Crab-eating Rat has been found over a very wide area, there are only a few scattered records, and very little is known about its status and habitat requirements.

Bibliography. Anthony (1923), Brito et al. (2016), Pacheco & Tirira (2008), Pacheco & Ugarte-Nunez (2011), Thomas (1893a), Voss (1988, 2015b).

Figures

321. Groove-toothed Cotton Rat (Sigmodon alstoni), 322. Ecuadorean Cotton Rat (Sigmodon inopinatus), 323. Peruvian Cotton Rat (Sigmodon peruanus), 324. White-eared Cotton Rat (Sigmodon leucotis), 325. Tawny-bellied Cotton Rat (Sigmodon fulviventer), 326. Yellow-nosed Cotton Rat (Sigmodon ochrognathus), 327. Hispid Cotton Rat (Sigmodon hispidus), 328. West Mexican Cotton Rat (Sigmodon mascotensis), 329. Arizona Cotton Rat (Sigmodon arizonae), 330. Toltec Cotton Rat (Sigmodon toltecus), 331. Allen’s Cotton Rat (Sigmodon alleni), 332. Burmeister’s Cotton Rat (Sigmodon hirsutus), 333. Montane Cotton Rat (Sigmodon zanjonensis), 334. Miahuatlan Cotton Rat (Sigmodon planifrons), 335. Musso’s Fish-eating Rat (Neusticomys mussoi), 336. Montane Fish-eating Rat (Neusticomys monticolus), 337. Voss’s Fish-eating Rat (Neusticomys vossi), 338. Venezuelan Fish-eating Rat (Neusticomys venezuelae), 339. Guianan Fish-eating Rat (Neusticomys oyapocki), 340. Ferreira’s Fish-eating Rat (Neusticomys ferreirai), 341. Peruvian Fish-eating Rat (Neusticomys peruviensis), 342. Northern Andean Water Mouse (Chibchanomys trichotis), 343. Orces’s Andean Water Mouse (Chibchanomys orcesi), 344. Earless Water Mouse (Anotomys leander), 345. Pittier’s Crab-eating Rat (Ichthyomys pittieri), 346. Common Crab-eating Rat (Ichthyomys hydrobates), 347. Tweedy’s Crab-eating Rat (Ichthyomys tweedii), 348. Stolzmann’s Crab-eating Rat (Ichthyomys stolzmanni), 349. Goldman's Water Mouse (Rheomys raptor), 350. Thomas's Water Mouse (Rheomys thomasi), 351. Underwood’s Water Mouse (Rheomys underwoodi), 352. Mexican Water Mouse (Rheomys mexicanus)

Distribution. Known from only three localities in E Andean piedmont of Ecuador and four localities in Peru.