Part 17

Additional records.--Rio de Janeiro, Itatiaia (Thomas, 1921:141); Rio de Janeiro, Zona da mata, Mont-Serrat, Serra do Itatiaia (Ribeiro, 1905:187).

=Proechimys iheringi= Thomas

General characters.--Size large; tail long; aristiforms generally wide and stiff; general color on upper parts and sides a combination of blackish from tips of aristiforms with cinnamon ground color from subapical zones of setiforms; darker band on middorsal line; differentiated light-colored aristiforms conspicuous on outer sides of thighs and rump; usually rufous tint on neck and postauricular region; underparts white; tail with white tip, usually accentuated by white brush; feet white on dorsal surface; hind feet slightly darker on outer sides; skull elongate and smooth; jugals wide dorso-ventrally; incisive foramen elongate; upper molariform teeth usually with one to five counterfolds, number varying with subspecies; lower premolar always with two counterfolds and lower molars always with one or two counterfolds.

Remarks.--As a whole, the samples of the populations of the species do not afford a satisfactory record of the distribution; my concept of the group may be changed when further collections are made in localities geographically intermediate between those from which specimens now are known. If some of the forms prove to be physiologically isolated, they may deserve treatment as full species according to the conventional standards of systematic zoology. P. panema, for example, does not seem to be geographically isolated from P. gratiosus. P. denigratus, at the northernmost known occurrence of the species, actually represents a striking jump in the cline, although collections from intermediate regions may provide intermediate structural stages. Further collecting may also prove that the southern form, P. iheringi iheringi, is completely isolated from the rest of the group. However, these samples are certainly more related to each other than any one of them is to that of the other species found in the same range, namely P. dimidiatus, and all the forms in question, therefore, seem best arranged as subspecies of one full species. A clinal variation certainly exists among these forms and the most striking differences correspond to larger geographical distances.

=Proechimys iheringi iheringi= Thomas

Proechimys iheringi Thomas, August, 1911, Ann. Mag. Nat. Hist., 8 (ser. 8):252 (orig. descr.); Thomas, 1921, Ann. Mag. Nat. Hist., 8 (ser. 9):141; Tate, 1935, Bull. Amer. Mus. Nat. Hist., 68(5):400; Ellerman, 1940, The families and genera of living rodents, Brit. Mus. (Nat. Hist.), 1:122.

Type locality.--Island of São Sebastião (off São Paulo), Formosa, São Paulo, Brazil. Type: British Museum (Nat. Hist.), no. 2.8.25.5, adult male, presented by the São Paulo Museum.

Range.--Littoral and islands of São Paulo and Rio de Janeiro.

Diagnosis.--Aristiforms narrow; tail shorter than head and body; setiforms Cinnamon-Buff; incisive foramen short; vomerine sheath complete; upper molariform teeth with two or three counterfolds; lower molariform teeth with two counterfolds, rarely one in m3.

Pelage.--Aristiforms on middorsal region: Gray basally, gradually blackening toward tip; total length 18 to 23 mm; maximum width, 0.6 mm. Aristiforms on outer thighs: Gray basally, blackening distally toward tip; some differentiated with Cinnamon-Buff tip. Setiforms on middorsal region: Gray basally, gradually blackening toward tip but interrupted by a Cinnamon-Buff, subapical zone 3 mm long; total length, 16 to 20 mm; maximum width, 0.06 mm. Setiforms on outer thighs: Gray basally, gradually blackening toward tip but interrupted by Cinnamon-Buff, subapical zone or with Cinnamon-Buff continuous to tip.

Skull.--Slender; bullae small and well inflated; jugal dorso-ventrally wide with transverse ridge inconspicuous; incisive foramen short, 3.5 × 2.5 mm; vomerine sheath complete; mesopterygoid fossa extending forward as far as middle parts of second molars; postorbital process of zygoma small, formed by both jugal and squamosal; posterior palatine foramina at plane of premolars; interorbital breadth narrow.

Teeth.--Upper molariform teeth with two or three counterfolds (when unworn usually three and rarely four); sometimes only one counterfold in M3 and sometimes counterfolds fused in molars. Lower molariform teeth with two counterfolds, rarely one in m3.

Comparisons.--From P. i. bonafidei and P. i. gratiosus, iheringi differs in: Incisive foramen shorter; vomerine sheath complete, instead of usually incomplete; setiforms Cinnamon-Buff, instead of Ochraceous-Buff; upper molariform teeth with two or three separate counterfolds, instead of having counterfolds fused or reduced to one or two; aristiforms narrower in iheringi than in bonafidei.

Specimens examined.--Total number, 25, from Brazil, as follows: São Paulo, Formosa, Ilha de São Sebastião, 9 (DZ 6, MN 2, MCZ 1); São Paulo, Mogi das Cruzes, Alto da Serra, alt. 900 m., 2 (DZ); São Paulo, Ubatuba, alt. 10 m., 4 (2 DZ, 2 MN); Rio de Janeiro, Angra dos Reis, 2 (MN); Rio de Janeiro, Angra dos Reis, Ilha Grande, 7 (5 DZ, 1 MCZ, 1 MN).

=Proechimys iheringi bonafidei= subspecies nova

Type locality.--Fazenda Bõa Fé, Teresópolis, Rio de Janeiro, Brazil; alt. 850 meters. Type: Museu Nacional, no. 6183, adult male; collected on 18 August, 1942, by G. Pereira; SEPFA no. M 14663.

Range.--Known only from the type locality.

Diagnosis.--Aristiforms wide and stiff; tail shorter than head and body; setiforms Ochraceous-Buff; incisive foramen long; vomerine sheath incomplete, or rarely complete; molariform teeth with two counterfolds usually fused.

Pelage.--Aristiforms on middorsal region: Gray basally, gradually blackening toward tip; total length, 22 to 26 mm; maximum width, 0.8 mm. Aristiforms on outer thighs: Gray basally, gradually blackening toward tip but interrupted by Ochraceous-Buff subapical zone; some Ochraceous-Buff to tip; total length, 18 to 20 mm; maximum width, 0.7 mm. Setiforms on middorsal region: Gray basally, gradually blackening toward tip but interrupted by Ochraceous-Buff, subapical zone; total length, 17 to 20 mm; maximum width, 0.06 mm. Setiforms on outer thighs: Gray basally, gradually blackening toward tip but interrupted by Ochraceous-Buff, subapical zone; only a short blackened tip.

Skull.--Large, with elongate rostrum; bullae large and well inflated; jugals with transverse ridge inconspicuous; postorbital process of zygoma small, formed mostly by squamosal; incisive foramen elongated (5.5 × 2.5 mm); vomerine sheath incomplete or, if complete, with maxillary part thin and delicate; posterior palatine foramen at plane of first molars; mesopterygoid fossa extending forward as far as middle parts of second molars.

Teeth.--Upper molariform teeth with two counterfolds; these completely separated in 3 of 16 specimens; two counterfolds coalesced in all three molars in 6 specimens; counterfolds coalesced in only two molars in 3 specimens; counterfolds coalesced in only one molar in 4 specimens. Lower molariform teeth with two counterfolds which are completely separated in 13 of 16 specimens; counterfolds coalesced in only one molar in 2 specimens; counterfolds coalesced in all three molars in one specimen.

Comparisons.--From P. i. gratiosus, bonafidei differs in: Aristiforms wider; tail shorter; molariform teeth with two counterfolds instead of one or two. Differences from P. i. iheringi are given in the account of that subspecies.

Remarks.--Of females with embryos two were captured in April and one in September. The embryos number 2, 1, 2. Young were captured mostly in April, but two were taken in July. Male gonads seemed to be most active in March, April and September. The animals lived in a second growth forest, approaching the climax. The rainfall was more than 1600 mm annually, and the mean annual temperature was 18.5° centigrade.

Specimens examined.--Total number, 18 (MN), from Brazil, Rio de Janeiro, Teresópolis, Fazenda Bõa Fé.

=Proechimys iheringi gratiosus= subspecies nova

Type locality.--Floresta da Caixa Dagua, Santa Teresa, Espirito Santo, Brazil; altitude 750 meters. Type: Museu Nacional, no. 4024, adult male; collected on 25 May, 1940, by C. Lako; SEPFA no. M 6911.

Range.--Known only from the type locality.

Diagnosis.--Aristiforms narrow; tail of same length as head and body; setiforms Ochraceous-Buff; incisive foramen long; vomerine sheath usually incomplete; upper molariform teeth with one or two counterfolds; lower molariform teeth with two counterfolds, except that m3 usually has only one.