Proechimys goeldii, Thomas, 1905

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 : 573-574

40.

Goeld 1’s Spiny-rat

Proechimys goeldii

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

Taxonomy. Proechimys goeldii Thomas, 1905 ,

“Santarem [Santarém |, Lower Ama-zon,” Rio Tapajos, Para, Brazil. Identified by M. Guntert and colleagues in 1993 as “Santarém, Barras de Tapajoz” (holotype specimen).

Proechimys goeldii is a member of the goeldi+ species group. It includes hyleae, nesiotes, and leioprimma as synonyms. Monotypic.

Distribution. E Amazon Basin of Brazil, mostly E of the Rio Madeira and S of the Amazon River, largely in the drainages of the Rio Tapajos, Rio Xingu, and Rio Tocantins-Araguaia, reaching the cerrado biome in Mato Grosso State.

Descriptive notes. Head—body 188-271 mm, tail 100-171 mm. No specific data are available for body weight. Goeldi’s Spiny-rat is a geographically variable; general size varies from large to medium, ears are long, hindfeet are large, and tail averages c.68% of head-body length. Dorsum is dark reddish brown, strongly mixed with black especially over mid-back and rump, but specimens from more southern localities are distinctly paler and more orangish red. Venter is clear white from chin to inguinal region; inner thighs are white but separated from dorsal foot color by dark band. Dorsal surface of hindfootis bicolored, with dark lateral band and light inner band—a pattern characteristic of the Napo Spiny-rat ( P. quadruplicatus ) and Steere’s Spiny-rat (P. steerer). All plantar pads of Goeldi’s Spiny-rat are well developed, with thenar and hypothenar large and sub-equal in size. Tail is covered with short, sparsely distributed hairs so that it appears naked to the eye. Tail scales are rather small, with average of 12 annuli/cm at mid-length. Aristiform spinesare stout and stiff, averaging 18-20 mm in length and up to 1-1 mm in width, and typically terminate in blunt tips. Skull of Goeldi’s Spinyrat is similar in most respects to the other two species in the goelditspecies group. It is large and elongate,is broad across zygomatic arches, and has relatively long but broad rostrum. Older individuals have weakly continuous temporal ridges, extending from supraorbital ledge across parietals. Incisive foramina are broadly open, weakly lyreshaped or parallel sided, with posterior margins slightly flanged and extending onto anterior palate forming grooves; premaxillary part of septum is short, usually less than one-half the length of opening; maxillary part varies greatly, often weak and attenuate, perhaps not in contact with premaxillary part, or even spatulate and filling much of posterior opening; maxillary part, however, has slight keel that continues onto palate as median ridge; and vomeris typically enclosed in premaxillary sheath and thus not visible. Floor of infraorbital foramen may be smooth, lacking any evidence of groove or with groove defined by moderately developed flange. Mesopterygoid fossa is moderately broad, with angle of indentation averaging 65°, but penetrates posterior palate to about midpoint of M?. Post-orbital process of zygoma is moderately developed and involves mostly squamosal. Counterfold pattern of cheekteeth varies, with number of folds decreasing from west to east and from north to south. Western specimens typically have upper cheekteeth with 3—4(3)—4(3)-3 and lower cheekteeth with 4(rarely 3)-3-3-3 folds; eastern and southern samples have reduced counterfold number of 3-3-3-3 above and 3 (rarely 4)-3-3-3 or 2 below. Baculum of Goeldi’s Spiny-rat is generally the same size and shape as those of the other members ofthis group, averaging slightly more than 8 mm in length and nearly 3 mm in width. Sides are straight and parallel, base is slightly expanded, and tip shows only faint development ofapical wings or median depression. Chromosomal complement is 2n = 15 and FN = 16 in Jurudna, Mato Grosso, Brazil and 2n = 24 and FN = 44 in Rio Xingu.

Habitat. Seasonally flooded blackwater (igap6) and whitewater (varzea) rainforest, both primary and secondary, and typically along river margins from near sea level to elevations of ¢.300 m.

Food and Feeding. There is no specific information available for this species, but Goe-Idi’s Spiny-rat, as other species of Proechimys , likely feeds on seeds,fruits, and other plant parts.

Breeding. Pregnant Goeldi’s Spiny-rats have been found in January at localities on Rio Tapajos and Rio Tocantins.

Activity patterns. There is no specific information available for this species, but Goe-1di’s Spiny-rat is presumably 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. Goeldi’s Spiny-rat is thought to be an abundant and present in undisturbed and deforested areas and other habitats highly modified by agricultural expansion throughoutits distribution. Apparentreliance on seasonally flooded forests, however, may protect Goe-Idi’s Spiny-rats from continued human expansion. Nevertheless, population studies on impact of habitat degradation are necessary to adequately assess its conservation status.

Bibliography. Bonvicino et al. (1996), Eisenberg & Redford (1999), Emmons (1990, 1997a), Gintert et al. (1993), Moojen (1948), Patton (1987), Patton & Gardner (1972), Patton & Leite (2015), Patton & Reig (1989), Thomas (1905a), 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. E Amazon Basin of Brazil, mostly E of the Rio Madeira and S of the Amazon River, largely in the drainages of the Rio Tapajos, Rio Xingu, and Rio Tocantins-Araguaia, reaching the cerrado biome in Mato Grosso State.