Figs. 39, 40. Proechimys semispinosus liminalis, female, MN no. 6253, Rio Quichito. Type. × 1.
Figs. 41, 42. Proechimys semispinosus amphichoricus, male, AMNH no. 77020, Mount Duida. Type. × 1.
Figs. 43, 44. Proechimys semispinosus kermiti, female, AMNH no. 37124, Lower Rio Solimões. Type. × 1.2 (from photograph).
Proechimys semispinosus liminalis subspecies nova
Type locality.—Rio Quichito, affluent from the south of the Javarí River, near Benjamin Constant, Benjamin Constant, Amazonas, Brazil. Type: Museu Nacional, no. 6253, adult female, collected in August, 1942, by E. Parko.
Range.—Known only from the type locality.
Diagnosis.—Color uniformly dark, setiforms marked with Ochraceous-Tawny; skull wide across zygomata; nasals short; prepalatilar part of skull long; incisive foramen long and narrow; vomerine sheath incomplete or complete; M2 and M3 almost always with four counterfolds; M1 more rarely with four counterfolds.
Pelage.—Aristiforms on middorsal region: Gray basally, gradually blackening toward tip which is generally extended as a filament; total length, 21 to 23 mm; maximum width, 0.9 to 1 mm. Setiforms on middorsal region: Gray basally, gradually blackening toward tip but interrupted by Ochraceous-subapical Tawny, zone 3 mm long; total length, 22 to 24 mm; maximum width, 0.06 mm. Setiforms on outer thighs: Whitish basally, gradually blackening toward tip but interrupted by Ochraceous-Buff, subapical zone 2.5 mm long; total length, 13 to 15 mm; maximum width, 0.08 mm; some with gray base, blackening gradually toward tip, without any subapical zone; some with Light Ochraceous-Tawny, subapical zone.
Skull.—Large and strongly built throughout; supraorbital ridges expanded and thick, extending, in old specimens, across parietals to anterior angles of interparietals; interparietal ridges always conspicuous; rostrum elongated; nasals blunt posteriorly; zygomatic arches strong; infraorbital foramen with weakly-developed groove for transmission of nerve; postorbital process of zygoma involving mostly squamosal; incisive foramen averaging 6 x 2.7 mm, widest in middle part and posteriorly constricted, with raised margins which do not extend across maxillae as ridges; posterior margin of incisive foramen approximately 1.5 mm anterior to plane of premolars; vomerine sheath incomplete or, sometimes, complete but always with maxillary part slender; mesopterygoid fossa not extending forward past centers of third molars; bullae moderately developed.