Rhombomys opimus sodalis, Goodwin, 1939

Goodwin, George G., 1939, Five Newrodents From The Eastern Elburz Moitntains And A New Race Of Hare From Teheran, American Museum Novitates 1050, pp. 1-6 : 4

Rhombomys opimus sodalis , new subspecies

Elburz Giant Gerbil

TYPE.-No. 88867 , Amer. Mus. Nat. Hist.; adult d; Maravih, Incha district; alt. about 2000 feet; collector, G. G. Goodwin, Nov. 15, 1938 . The type is a skin and skull in good condition. Besides the type there are 22 topotypes including 12 specimens in spirits and 6 specimens from Dasht, alt. 3200 feet, on the headwaters of the Gurgan River.

GENERAL CHARACTERS.-A pinkish cinnamon gerbil about the size of R. opimus from the sandy wastes on the northeast shore of the Aral Sea but differing in coloration.

DESCRIPTION.-Color above in general tone pinkish cinnamon, overlaid with black; the hairs dark neutral gray at base followed by a broad band of light ochraceous buff and tipped with black, darkest on crown of head and rump; sides of body, light buff; upperside of fore and hind feet, ring around eye, and ears, light buff; tail, uniform cinnamon-buff with a crest of black hairs on distal half; under parts buffy white, the light buff of sides extending irregularly over much of under parts; base of hairs dark neutral gray. Skull, massive; front incisors with two grooves, characteristic of genus; similar to R. opimus but interparietal broader and molariform teeth larger.

MEASUREMENTS.-Type (skin measured in the flesh); topotypes (adult e and adult 9) in parentheses. Total length, 320 (354, 300); tail vertebrae, 140 (155, 135); hind foot including claws, 45 (44.6, 43).

SKULL.-Greatest length, 45.9 (44.6, 43); condylo-incisive length, 41 (40.4, 39.1); interorbital constriction, 8 (8, 7.6); zygomatic width, 25.8 (26.7, 25.8); length of nasals, 17.2 (16.7, 16.9); interparietal, length 5.4 (6, 5.1), width 7.9 (8.7, 9.4); bullae 16.3 (16, 15); alveoli of upper molar series, 7.5 (7.4, 7).

REMARKS.-All the known forms of Rhombomys are closely allied, showing little variation in cranial characters and having a wide range in Central Asia.

R. o. sodalis requires comparison only with R. o. opimus from the sandy wastes, northeast of the Aral Sea and R. o. fumicolorfrom the Syr-Daria, 35 miles northeast of Kokand. Both forms inhabit low desert areas whereas the new race was taken on the upland plateaus from 2000 to 3000 feet elevation in northeastern Iran where a new geographical race might be expected. Typical R. opimus averages smaller than sodalis and coloration more yellowish. R. o. fumicolor is larger than the Iran race and pelage dark grayish instead of pinkish cinnamon.