The black-tailed jack rabbit is the only species of _Lepus_ known from
Tamaulipas and is represented there by three subspecies, _L. c.
merriami_ of the northern part of the state, _L. c. altamirae_ of the
southeastern coastal plains, and _L. c. curti_ of the barrier beach
south of Matamoros. The known ranges of the three subspecies are not
presently known to meet in Tamaulipas.
=Lepus californicus altamirae= Nelson
1904. _Lepus merriami altamirae_ Nelson, Proc. Biol. Soc.
Washington, 17:109, May 18, type from Altamira, Tamaulipas.
1951. _Lepus californicus altamirae_, Hall, Univ. Kansas
Publ., Mus. Nat. Hist., 5:45, October 1.
_Distribution in Tamaulipas._--Southern coastal plain north
certainly to vicinity of Soto la Marina.
The two specimens examined in this study (see below) are intermediate
between _L. c. altamirae_ and _L. c. curti_, but show greater
resemblance to the former. In measurements they resemble _altamirae_
rather than the smaller _curti_. They approach the latter in length of
hind foot and are intermediate between the two subspecies in basilar
length; in one specimen, the dimensions of the rostrum are as in
_curti_ and the other has the black patch on the posterior surface of
the ear well developed, as in _altamirae_, but in the other the black
is reduced. _L. c. altamirae_ has been known previously only from
Altamira.
_Measurements._--Two male adults (55415, 55416) from north
of Soto la Marina, afford the following external
measurements: 610, 590; 100, 100; 124, 125; 124, 122 (length
of ear from notch, dry, 114, 110). Cranial measurements are:
basilar length, 75.1, 74.4; length of nasals, 46.1, 41.9;
width of rostrum at PM, 25.1, 28.7; height of rostrum in
front of PM, 25.2, 21.5; diameter of auditory bulla, 14.1,
13.0.
_Records of occurrence._--Specimens examined, 2: 3 mi. N
Soto la Marina, 1; 2 mi. NW Soto la Marina, 1.
Additional record: Altamira (Nelson, 1904:109).
=Lepus californicus curti= Hall
1951. _Lepus californicus curti_ Hall, Univ. Kansas Publ.,
Mus. Nat. Hist., 5:42, October 1, type from barrier beach 88
mi. S, 10 mi. W Matamoros, Tamaulipas.
_Distribution in Tamaulipas._--Known only by the three
specimens mentioned in the original description from two
barrier islands in northeastern part of state.
_Records of occurrence._--Specimens examined, 3: 88 mi. S,
10 mi. W Matamoros, 2; 90 mi. S, 10 mi. W Matamoros, 1.
=Lepus californicus merriami= Mearns
1896. _Lepus merriami_ Mearns, Preliminary diagnoses of new
mammals from the Mexican border of the United States, p. 2,
March 25, type from Fort Clark, Kinney Co., Texas.
1909. _Lepus californicus merriami_, Nelson, N. Amer. Fauna,
29:148, August 31.
_Distribution in Tamaulipas._--Northern and western parts of
state.
The two specimens examined, an adult female and a young male, from the
barrier beach 33 miles south of Washington Beach are intergrades
between _L. c. merriami_, reported from the mainland from as near as
Matamoros, and _L. c. curti_, which occurs farther to the south on the
same series of barrier beaches. Of seven characters that seem to
differentiate the two subspecies, the adult female from 33 miles south
of Washington beach resembles _merriami_ in four as follows: tips of
ears black (white in _curti_); nasals long; hind foot long; and
supraoccipital process broad. The specimen resembles _curti_ in
shortness of tail and in having small auditory bullae. Breadth of
rostrum above premolars, the seventh character, is less than in typical
specimens of either of the two subspecies. More material is needed from
the barrier beach in order to establish with certainty the
relationships between jack rabbits occurring there.
_Records of occurrence._--Specimens examined, 4: 33 mi. S
Washington Beach, 2; 12 mi. NW San Carlos, 1300 ft., 2.
Additional records: Nuevo Laredo (Nelson, 1909:150); Mier
(_ibid._); Camargo (_ibid._); Matamoros (Hall, 1951:185);
Tamaulipeca, San Carlos Mts. (_ibid._).
=Spermophilus mexicanus parvidens= Mearns