Calomyscus elburzensis, 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 : 1-2

Calomyscus elburzensis , new species

Elburz Vesper Mouse

TYPE.-NO. 88838 , Amer. Mus. Nat. Hist.; adult 9, Degermatie, Kurkhud Mountains, district of Bujnurd , Iran; alt. 4000 feet; collector, G. G. Goodwin, Nov. 14, 1938. The type is a skin and skull in good condition. Besides the type there are 4 topotypes.

GENERAL CHARACTERS.-A rather small lightcolored mouse with soft thick pelage; tail well haired, pencilled but not bushy terminally, about equal in length to head and body; ears rather small for the genus; very similar in cranial and external characters to North American Peromy 8 cus.

DESCRIPTIoN.-Color above pinkish buff, heavily overlaidwith blackish mouse-gray. The hairs plumbeous black at base, followed by a broad band of pinkish buff and tipped with black mouse-gray; an ill-defined lateral line, clear pinkish buff, slightly richer in color than back; front of face light buff, the dark tips of hairs inconspicuous. Under parts, including fore and hind feet and well up on sides of face and nose, pure white to base of hairs; ears, dark brown, sparsely covered with short fine dusky hairs; tail, above, clove-brown to tip; below, white.

SKULL.-Low and flat; braincase rounded; rostrum long and slender; bullae small; zygomatic arches weak, narrower anteriorly than posteriorly; palatal foramina long and narrow, ending posteriorly about 8 mm. in front of a line across f&st molars; interparietal relatively short and broad; molariform teeth small, 5 low cusps on first molar normal for the genus.

MEASUREMENTS.-Skin measured in the field. Total length, 160 mm.; head and body, 80; tail, 80; hind foot including claws, 21; ear from notch in dried skin, 12.3. Skull: greatest length, 25; condylo-incisive length, 21.9; basal length, 20; palatal length, 11.6; length of nasals, 9.4; zygomatic breadth, 12.8; interorbital breadth, 4.1; breadth of braincase, 11.5; alveoli of upper molar series, 3.3; palatine foramina, 4.4; interparietal, 3 X 9.3.

REMARKS.- Calomyscus elburzensis is a short-eared form readily distinguished from C. bailwardi Thomas (west central Iran) and C. baluchiThomas (Kelat, Baluchistan) byits smallsize, much smaller ears and distinctive cranial characters. It is similar in general structure to C. hotsoni Thomas (Gwanbuk Kawl, sw. of Panigur Baluchistan) but differs from the latterinitslarger size, relatively shorter tail, smaller ears, shorter palatine foramina, wider interparietal region and paler color. The type of C. mystax Kashkarov came from the Great Balkan Mountains, Transcaspia. Kashkarov's description is brief, external measurements are not given, only three cranialmeasurements; colorisdescribedas avellaneous, not much shaded with black. Besides the color differences the Great Balkan Mountains race has molar teeth 3.4-3.6, as compared with 3.2-3.4 in the elburzensis , and alonger andnarrowerinterparietal, 3.6 X 8.3 as compared with 3 X 9.3 in the present species. C. elburzensis is probably closely allied to either C. hotsoni or C. mystax . A comparison of specimens of the three species may show that either elburzensis or mystax or both are subspecies of hotsoni .

The present series were trapped on a bleak, barren rocky mountain ridge. None was taken in more sheltered areas fifty feet lower where vegetation was plentiful. The five specimens are all adults and in early winter pelage. When taken, the first snow had alreadyfallen and temperature at night dropped below freezing point.