Part 10

Comparisons.--The subspecies is easily distinguishable from P. s. angularis by: larger number of black setiforms on back, forming an almost black longitudinal band; more elongate skull; larger and longer bulla; longer incisive foramen which is more constricted posteriorly.

Specimens examined.--Total number, 6 (AMNH), as follows: Venezuela, territ. Amazonas, Esmeralda, Mt. Duida, altitude 325 m., 4; Venezuela, territ. Amazonas, Rio Cassiquiare, Quemapuré, 1; Brazil, Amazonas, São Gabriel, Rio Uaupés or Caiari, Tatú, 1.

=Proechimys semispinosus kermiti= Allen

Proechimys kermiti Allen, 30 December 1915, Bull. Amer. Mus. Nat. Hist., 34(22):629 (orig. descr.); Allen, 1916, Bull. Amer. Mus. Nat. Hist., 35(30):569; Tate, 1935, Bull. Amer. Mus. Nat. Hist., 68(5):400; Ellerman, 1940, The families and genera of living rodents, Brit. Mus. (Nat. Hist.), 1:119.

Type locality.--Lower Rio Solimões (up the Solimões 50 to 60 miles on the north bank of the river), Manacaparú, Amazonas, Brazil. Type: American Museum of Natural History, no. 37124, adult female; collected 20 April, 1914, by Leo E. Miller (Roosevelt Brazilian Expedition).

Range.--Known only from type locality.

Diagnosis.--Upper parts Tawny, with darker longitudinal band on back, gradually becoming Ochraceous-Buff on sides; zygomata widely spread; nasals long; incisive foramen long; vomerine sheath incomplete; only M3 with four counterfolds.

Pelage.--Aristiforms on middorsal region: Grayish basally, gradually blackening toward tip; total length, 18 to 20 mm; maximum width, 0.8 mm. Setiforms on middorsal region: Grayish basally, gradually blackening toward tip but interrupted by Tawny, subapical zone 2 mm long; total length, 18 to 20 mm; maximum width, 0.06 mm; some blackened toward tip without subapical zone. Setiforms on outer thighs: Whitish basally, gradually blackening toward tip but interrupted by Ochraceous-Buff, subapical zone 2.5 mm long; total length, 18 to 20 mm; maximum width, 0.05 mm.

Skull.--Large, elongate, and strongly built; rostrum not conspicuously elongated; nasals bluntly pointed posteriorly; supraorbital ridges wide and extending posteriorly across parietals almost to level of interparietal; infraorbital foramen with moderate development of groove for transmission of nerve; zygomatic arches slender; postorbital process of zygoma involving mostly squamosal; incisive foramen 6.5 mm long and 2.7 mm wide, wider in anterior third and gradually constricted posteriorly, with margins extended toward palate as ridges; vomerine sheath incomplete, maxillary part threadlike; mesopterygoid fossa extending forward as far as anterior third of m3; bullae large and well inflated.

Teeth.--P4 with three counterfolds; M3 with four counterfolds; M1 and M2 with three counterfolds. Lower premolars with four counterfolds; lower molars with three counterfolds.

Comparisons.--From P. s. amphichoricus, kermiti differs in: upper parts Tawny instead of Buckthorn Brown; incisive foramen longer and wider; vomerine sheath incomplete; only M3 instead of usually all molars, with four counterfolds. From P. s. liminalis, kermiti differs in: upper parts Tawny instead of Ochraceous-Tawny; aristiforms narrower; M3 only, instead of usually M2 and M3, with four counterfolds.

Specimens examined.--Only the type.

=Proechimys longicaudatus= (Rengger)

General characters.--Size medium to large; tail short; aristiforms long and narrow; general color on upper parts Ochraceous-Buff to Ochraceous-Orange, finely and uniformly lined with blackish and not forming evident dark band on back; feet dorsally white or gray; underparts of body and inner sides of legs white; skull elongate and slender with moderate ridges; incisive foramen of medium size; vomerine sheath complete or incomplete; bullae large and elongate; upper molariform teeth with three counterfolds; lower molariform teeth with three counterfolds but commonly one or two molars have only two although premolar may have four.

Remarks.--The identity of "Echimys longicaudatus Rengger" can be ascertained only after samples have been collected in the area indicated by Rengger: "unter dem ein und zwansigsten Breitengrade" in Paraguay. Of the samples available to me, those from Urucum, in western Brazil, are geographically nearest the type locality. North of Urucum, both in Brazil and Bolivia, two species of Proechimys live together and one of them is the same species as that at Urucum. Of the two species found to the northward in Brazil and Bolivia, the one that ranges farther south probably will occur at the locality indicated by Rengger. Provisionally, therefore, the name longicaudatus is allocated to the Urucum sample (see Osgood, 1944:198). In fact, the lack of a type specimen and the general nature of Rengger's description make "Echimys longicaudatus" a nomen vanum. If two species are found living together in the region of northern Paraguay indicated by Rengger it probably will be impossible to be sure to which one his vague description applies.

The form from Urucum, to which the name Proechimys longicaudatus is here applied, is undoubtedly closely related to Proechimys leucomystax Ribeiro, from Utiarití, on the Rio Papagaio and also to P. roberti and P. boimensis, all from Brazil. P. longicaudatus is used as the name of the species because it is the oldest of the four names.

=Proechimys longicaudatus brevicauda= (Günther)

Echimys brevicauda Günther, 1 April 1877, Proc. Zool. Soc. London for 1876, (49):748, fig. 9.

Proechimys brevicauda Ihering, 1904, Rev. Mus. Paulista, S. Paulo, 6:422; Osgood, 1914, Zool. Ser. Field Mus. Nat. Hist., 10(12):168; Thomas, 1924, Ann. Mag. Nat. Hist., 13 (ser. 9):534; Thomas, 1927, Ann. Mag. Nat. Hist., 19 (ser. 9):553; Thomas, 1927, Ann. Mag. Nat. Hist., 20 (ser. 9):604; Thomas, 1928, Ann. Mag. Nat. Hist., 2 (ser. 10):262; Thomas, 1928, Ann. Mag. Nat. Hist., 2 (ser. 10):292; Tate, 1935, Bull. Amer. Mus. Nat. Hist., 68 (5):399; Osgood, 1944, Zool. Ser. Field Mus. Nat. Hist., 29 (13):201.

Proechimys cayennensis brevicauda Ellerman, 1940, The families and genera of living rodents, Brit. Mus. (Nat. Hist.), 1:120.

Type locality.--Chamicuros, Rio Huallaga, Peru. Type: British Museum (Nat. Hist.), no. 69.3.31.7,; Lectoparatype: British Museum (Nat. Hist.), no. 66.1.29.8, from Upper Amazons (E. Barttet), selected by Thomas (1900:301).

Range.--Region of the headwaters and upper courses of the Juruá and Ucaiali rivers, eastern Peru and northwestern Brazil.

Diagnosis.--Upper parts Tawny and blackish without marked longitudinal band on back; underparts buffy or white; aristiforms narrow; skull slender; incisive foramen wide; vomerine sheath complete; molariform teeth with three counterfolds, except p4 with four and m3 with only two.

Pelage.--Aristiforms on middorsal region: Blackish basally, gradually blackening toward tip which is extended as a long filament; total length, 18 to 20 mm; maximum width, 0.65 mm. Setiforms on middorsal region: Gray basally, gradually blackening toward tip but interrupted by Tawny, subapical zone 1.2 mm long; total length, 19 to 21 mm; maximum width, 0.1 mm. Setiforms on outer thighs: Whitish basally, gradually blackening toward tip but interrupted by Ochraceous-Tawny, subapical zone 3 mm long.

Skull.--Slender but not elongated; nasals tapering posteriorly; interparietals wide; supraorbital ridges not much extended and faintly shown across parietals; jugals dorso-ventrally "wide" (3.5 mm); postorbital process of zygoma weakly developed; incisive foramen 5.5 x 3 mm, oval, with posterior borders raised to form ridges which extend toward premolars; vomerine sheath complete, with maxillary part laterally compressed and extended toward palate as ridge; mesopterygoid fossa extending forward as far as third molars; bullae large and well inflated.

Teeth.--Molariform teeth with three counterfolds, except p4 which has four and m3 which has only two counterfolds.

Comparisons.--From P. l. longicaudatus, brevicauda differs in: upper parts Tawny instead of Ochraceous-Buff; lower premolar with four instead of three counterfolds; m3 only, instead of both m1 and m3, with two counterfolds. From P. l. boimensis, brevicauda differs in: upper parts Tawny instead of Ochraceous-Orange; aristiforms wider; m3 with two instead of three counterfolds.

Specimens examined.--Total number, 3 (DZ), from Brazil, Amazonas, João Pessoa, Rio Juruá.