Dipodomys ordii attenuatus Bryant, Occas. Papers, Museum of Zool., Louisiana State Univ., no. 5:65, November 10, 1939.
Type.—Male, no. 80429, Museum of Vertebrate Zoology, University of California; Mouth of Santa Helena Canyon, 2146 ft., Big Bend of the Rio Grande, Brewster County, Texas; obtained on November 19, 1938, by Adrey E. Borell, original no. 5581.
Range.—Big Bend region of Brewster County, Texas.
Diagnosis.—Size small (see measurements). Color light, entire dorsal surface between Pinkish Buff and Pinkish Cinnamon, purest on sides and flanks, upper parts but lightly mixed with black; cheeks and narrow outer margin of ear, pure white; arietiform markings absent; pinnae of ears, dorsal and ventral stripes of tail, brownish; plantar surfaces of hind feet, blackish. Skull small; rostrum long and narrow; nasals short; interparietal longer than wide; auditory bullae longer than deep.
Comparisons.—Compared with Dipodomys ordii ordii, D. o. attenuatus differs in: Size smaller; color lighter; skull smaller; nasals thinner; rostrum narrower; auditory bullae less inflated.
From Dipodomys ordii richardsoni, D. o. attenuatus differs in smaller size and lighter color. Skull smaller in all respects.
For comparison with Dipodomys ordii sennetti see account of that subspecies.
