ethrionomys gapperi limitis+ (Bailey)

1913. _Evotomys limitis_ Bailey, Proc. Biol. Soc. Washington, 26:133,
May 21.

_Type locality._--Willow Creek, a branch of the Gilita, 8500 ft.,
Mogollon Mountains, Catron County, New Mexico.

_Range._--Known from the Mogollon, San Mateo, and Magdalena mountains
of western New Mexico.

_Remarks._--Bailey (Proc. Biol. Soc. Washington, 26:133, May 21,
1913) described this animal as a species and gave as general
characteristics: "Size slightly larger than _E._ [= _Clethrionomys
gapperi_] _galei_; colors duller, grayer and less buffy; skull and
dentition heavier." He further characterized the skull as: "Larger,
heavier and conspicuously more ridged than in _galei_; bullae large
and especially deep; dentition heavy throughout." The type of _C.
limitis_, as judged from the measurements given by Bailey (_loc.
cit._), is an exceptionally old male.

Our comparison of six adult topotypes with a series of _C. g. galei_
from Wyoming (18 adults from 3 mi. SSE Browns Peak, 10,000 ft., Albany
County, in Univ. Kansas Mus. Nat. Hist.) and with three near-topotypes
of _C. g. galei_ (3 mi. S Ward, 9000 ft., Boulder County, Colorado, in
Univ. Kansas Mus. Nat. Hist.) revealed that most of the differences
noted by Bailey (_loc. cit._) are not evident when individuals of
comparable ages are examined. Some specimens of _C. g. galei_ exceed
_C. limitis_ in ridging of the skull and size of the teeth although
conspicuous ridges and large teeth are supposedly distinctive of _C.
limitis_. The bullae, although averaging larger in _C. limitis_, can
be matched in size by those of specimens of _C. g. galei_ from
Wyoming.

The differences evident between _C. limitis_ and _C. g. galei_ are of
the kind and degree that serve to separate subspecies in the species
_Clethrionomys gapperi_ and, although actual evidence of
intergradation is lacking, we think that the relationships of
_limitis_ are better expressed by arranging it as a subspecies of _C.
gapperi_ than by retaining it as a full species.

_Specimens examined._--Total, 7, all in the Biological Surveys
Collection, distributed as follows:

+New Mexico+: _Catron County_: Willow Creek, 8500 ft., Mogollon
Mountains, 4. _Socorro County_: San Mateo Peak, 10,000 ft., San Mateo
Mountains, 2; Copper Canyon, 9000 ft., Magdalena Mountains, 1.

+Clethrionomys gapperi arizonensis+, new subspecies

_Type._--Female, adult, skin and skull; No. 158401, Bi