Oecomys roberti (Thomas, 1904)

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 : 421

390.

Robert's Arboreal Rice Rat

Oecomys roberti

French: Oecomys de Robert / German: Robert-Baumreisratte / Spanish: Rata arrocerra arboricola de Robert

Other common names: Robert's Oecomys

Taxonomy. Rhipidomys roberti Thomas, 1904 , “Santa Ana de Chapada, a village stinated at an altitude of about ¢. 800 m, on the Serra do Chapada, some thirty miles [= 48 km] N.E. Cuyaba,” Mato Grosso, Brazil.

Taxonomy of O. roberti is poorly explored; unpublished metric studies recovered several different groups that need additional research. Monotypic.

Distribution. SE Colombia, E & S Venezuela, Guyana, Suriname, N & WC Brazil, E Peru, and extreme N & E Bolivia.

Descriptive notes. Head-body 111-135 mm, tail 138-164 mm, ear 14-17 mm, hindfoot 26-28 mm; weight 46-66 g. Robert's Arboreal Rice Rat is moderately large, with tail ¢.123% of head-body length and relatively short furforits body size (5-7 mm over mid-rump). Dorsal pelage is soft but slightly harsh to touch. Upperparts are bright tawny to fulvous brown, grading to ocherous on flanks, although without obvious lateral line. Venter ranges from all white (hairs single colored) to grayish white (hairs with gray bases and white tips), with varying degrees of intermediacy depending upon extent of gray-based hairs, or sometimes tinted with buffy or ocherous wash on chest and belly; dorsal and ventral pelage contrasts sharply in individuals with mostly white underparts but only moderately in individuals with grayish white or grayish buff venters. Tail is wholly dark brown; caudal hairs are so short thattail appears naked macroscopically, revealing fine scale rows, and no tuft at tip is formed. Pinnae are relatively short and brown; tops of hindfeet are white or tinged ocherous. Chromosomal complement is 2n = 80, FN = 114.

Habitat. Varzea forest along Jurua River, more rarely edges of second growth forest, ecotones of dense growth around natural tree falls in primary forest, viney forest with low canopy, and semideciduous forest from sea level up to elevations of ¢.800 m.

Food and Feeding. No information.

Breeding. Litters of Robert’s Arboreal Rice Rats have 2-3 young.

Activity patterns. Robert’s Arboreal Rice Rats were captured equally on the ground and in the canopy.

Movements, Home range and Social organization. No information.

Status and Conservation. Classified as Least Concern on The IUCN Red List.

Bibliography. Carleton & Musser (2015), Carleton et al. (2009), Costa, Weksler & Bonvicino (2016), Emmons et al. (2006), Hershkovitz (1960), Linares (1998), Patton et al. (2000).

Figures

353. Bogota Grass Mouse (Neomicroxus bogotensts), 354. Ecuadorean Grass Mouse (Neomucroxus latebricola), 355. Altiplano Chinchilla Mouse (Chinchillula sahamae), 356. Small Red-nosed Tree Mouse (Juliomys pictipes), 357. Delicate Red-nosed Tree Mouse (Juliomys ossitenuis), 358. Montane Red-rumped Tree Mouse (Juliomys rimofrons), 359. Araucaria Forest Tree Mouse (Juliomys ximenezi), 360. Ruschi’s Spiny Mouse (Abrawayaomys ruschii), 361. Chebez’s Spiny Mouse (Abrawayaomys chebezi), 362. Montane Atlantic Forest Rat (Delomys altimontanus), 363. Pallid Atlantic Forest Rat (Delomys sublineatus), 364. Striped Atlantic Forest Rat (Delomys dorsalis), 365. North-western Conyrat (Reithrodon caurinus), 366. Naked-soled Conyrat (Reithrodon typicus), 367. Hairy-soled Conyrat (Reithrodon awritus), 368. Short-tailed Cane Mouse (Zygodontomys brevicauda), 369. Colombian Cane Mouse (Zygodontomys brunneus), 370. Ucayali South American Spiny Mouse (Scolomys ucayalensts), 371. Gray South American Spiny Mouse (Scolomys melanops), 372. Boquete Rice Rat (Nephelomys devius), 373. Santa Marta Rice Rat (Nephelomys maculiventer), 374. Mount Pirre Rice Rat (Nephelomys pirrensis), 375. Western Colombian Rice Rat (Nephelomys pectoralis), 376. Coastal Cordilleran Rice Rat (Nephelomys caracolus), 377. Merida Rice Rat (Nephelomys meridensis), 378. Child’s Rice Rat (Nephelomys childi), 379. White-throated Rice Rat (Nephelomys albigularis), 380. Greater Golden-bellied Rice Rat (Nephelomys aurirventer), 381. Gray-bellied Rice Rat (Nephelomys moerex), 382. Lesser Golden-bellied Rice Rat (Nephelomys nimbosus), 383. Keays’s Rice Rat (Nephelomys keaysi), 384. Nimble-footed Rice Rat (Nephelomys levipes), 385. Hammond's Rice Rat (Mindomys hammondi), 386. White-bellied Arboreal Rice Rat (Oecomys bicolor), 387. Yellow Arboreal Rice Rat (Oecomys flavicans), 388. Savanna Arboreal Rice Rat (Oecomys speciosus), 389. Long-furred Arboreal Rice Rat (Oecomys trinitatis), 390. Robert's Arboreal Rice Rat (Oecomys robert), 391. Unicolored Arboreal Rice Rat (Oecomys concolor), 392. Guianan Arboreal Rice Rat (Oecomys awyantepui), 393. King Arboreal Rice Rat (Oecomys rex), 394. Red Arboreal Rice Rat (Oecomys rutilus), 395. Brazilian Arboreal Rice Rat (Oecomys paricola), 396. Foothill Arboreal Rice Rat (Oecomys superans), 397. Dusky Arboreal Rice Rat (Oecomys phaeotis), 398. Mamore Arboreal Rice Rat (Oecomys mamorae), 399. Anderson’s Arboreal Rice Rat (Oecomys sydandersoni), 400. Franciscos’ Arboreal Rice Rat (Oecomys franciscorum), 401. Atlantic Forest Arboreal Rice Rat (Oecomys catherinae), 402. Cleber’s Arboreal Rice Rat (Oecomys cleber), 403. McConnell’s Rice Rat (Euryoryzomys macconnelli), 404. Emmons’s Rice Rat (Euryoryzomys emmonsae), 405. Big-headed Rice Rat (Euryoryzomys legatus), 406. Russet Rice Rat (Euryoryzomys russatus), 407. Bufty-sided Rice Rat (Euryoryzomys lamia), 408. Elegant Rice Rat (Euryoryzomys nitidus), 409. Long-whiskered Rice Rat (Transandinomys bolivaris), 410. Talamancan Rice Rat (Transandinomys talamancae), 411. Long-nosed Rice Rat “ Handleyomys (™ rostratus), 412. Chapman’s Rice Rat “ Handleyomys (” chapman), 413. Black-eared Rice Rat “ Handleyomys (™ melanotis), 414. Guerrero Rice Rat “ Handleyomys (™ guerrerensis), 415. Cloud Forest Rice Rat “ Handleyomys (” saturatior), 416. Highland Rice Rat “ Handleyomys (” rhabdops), 417. Alfaro’s Rice Rat “ Handleyomys (” alfaroi), 418. Colombian Western Andes Cloud Forest Mouse (Handleyomys fuscatus), 419. Colombian Central Andes Cloud Forest Mouse (Handleyomys intectus)

Distribution. SE Colombia, E & S Venezuela, Guyana, Suriname, N & WC Brazil, E Peru, and extreme N & E Bolivia.