Proechimys pattoni, da Silva, 1998

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 : 575

43.

Patton’s Spiny-rat

Proechimys pattoni

French: Rat-épineux de Patton / German: Patton-Kurzstachelratte / Spanish: Rata espinosa de Patton

Taxonomy. Proechimys pattoni da Silva, 1998 ,

“Igarapé Porongaba, right bank Rio Jurua, 70°51°W, 6°45’S, Acre, Brazil.”

Proechimys pattoni is the third small-bodied member of the gardnerispecies group that occurs in western Amazonia. Monotypic.

Distribution. W Amazonian Basin, known only from the headwaters of the Rio Jurua in W Brazil and E & SE Peru.

Descriptive notes. Head-body 146-193 mm, tail 106-141 mm; weight 100-120 g. Patton’s Spiny-rats are slender, with short ears (21 mm), proportionally mid-length tail (c.70% of head-body length), and short hindfeet (41 mm). Overall body color varies between reddish brown to auburn, but it is coarsely streaked with varying amounts of black on back and sides. Interspersed dark brown aristiform spines give mid-back a dark aspect, but contrast between color of back and sidesis not sharp.

Venter, chin, and sides of upper lips are pure white. Dark ring around tarsal joint interrupts white of inner hindlimbs. Dorsal surfaces of hindfeet are entirely white. Six pads characterize plantar surfaces of hindfeet. Dark brown dorsal surface of tail grades evenly, rather than sharply contrasting, with paler brown to cream color of its ventral surface. Scales are small, with 11 annuli/cm on average in mid-part oftail. Dorsal pelage is stiff to the touch, although spines are both shorter (16-17 mm) and narrower (0-6—0-7 mm) than those of other species in the group, but also with blunt tips. Skull of Patton’s Spiny-rat is small and delicate in appearance, with overhanging supraorbital ledges and weakly developed beading extending onto temporal regions. Low but distinct post-orbital process of zygoma is present, usually formed solely by squamosal. Floor of infraorbital foramen is smooth, lacking even hint of a groove. Incisive foramina are ovate to nearly square, with flat posterolateral margins, attenuate or dorsoventrally compressed maxillary part of septum, and broad and short premaxillary part, which usually is not in contact with maxillary part. Palate is smooth, without median ridge. Mesopterygoid fossa is long and narrow; angle of indentation is acute (50-60°) and may penetrate the palate as far as M*. Cheekteeth are markedly small, with entire tooth row less than 7-5 mm in length. All upper cheekteeth typically have three lateral folds; lower cheekteeth typically have three folds, but dP, may have four and M, may only have two; counterfold formula is therefore 3-3-3-3/3(4)-3-3-2(3). Baculum is massive, especially in proportion to body size: length 7-4-9-1 mm, proximal width 4-2-5-1 mm, and distal width 3-1-4-2 mm. It has broad shaft, thick and expanded base, and long pair of distally divergent apical extensions, separated by wide and very deep median depression. Chromosomal complementis 2n = 40 and FN = 56.

Habitat. Known only from upland, non-seasonally flooded (terra firma) rainforest in undisturbed forest and disturbed areas dominated by bamboo.

Food and Feeding. There is no information available for this species.

Breeding. Pregnant Patton’s Spiny-rats were collected in the rainy season in western Brazil, with a modal littler size of two (range 1-2 embryos).

Activity patterns. There is no specific information available for this species, but trap records indicate that Patton’s Spiny-rat is terrestrial and 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. Little is known about Patton’s Spiny-rat, butits distribution is within a large area of western Amazonia that has been impacted little by humans other than scattered indigenous tribes. Additional studies on distribution, habitat, abundance, ecology, and conservation threats to Patton’s Spiny-rat are needed.

Bibliography. Patton & Leite (2015), Patton et al. (2000), da Silva (1998), Woods & Kilpatrick (2005).

Figures

12. Broad-headed Spiny-rat (Clyomys laticeps), 13. Guiara (Euryzygomatomys spinosus), 14. White-spined Spiny-rat (Irinomys albispinus), 15. Elias’s Spiny-rat (Trinomys eliasi), 16. Rigid-spined Atlantic Spiny-rat (Trinomys paratus), 17. Yonenaga’s Spiny-rat (Trinomys yonenagae), 18. Elegant-spined Atlantic Spiny-rat (Trinomys setosus), 19. Moojen’s Spiny-rat (Trinomys moojeni), 20. Pau Brasil Spiny-rat (Trinomys mirapitanga), 21. Rio de Janeiro Spiny-rat (Trinomys dimidiatus), 22. Sao Paulo Spiny-rat (Trinomys thering), 23. Gracile Atlantic Spiny-rat (Trinomys gratiosus), 24. Sao Lourenco Punare (Thrichomys laurentius), 25. Jacobina Punare (Thrichomys inermis), 26. Lagoa Santa Punare (Thrichomys apereoides), 27. Pantanal Punare (Thrichomys pachyurus), 28. Foster’s Punare (Thrichomys fosteri), 29. Painted Tree-rat (Callistomys pictus), 30. Coypu (Myocastor coypus), 31. Armored Rat (Hoplomys gymnurus)

Distribution. W Amazonian Basin, known only from the headwaters of the Rio Jurua in W Brazil and E & SE Peru.