The Amphibians and Reptiles of Sinaloa, Mexico - Smithsonian ...

136 UNIVERSITY OF KANSAS PUBLS., MUS, NAT. HIST.
Sceloporus nelsoni Cochran
Sceloporus nelsoni Cochran, Jour. Washington Acad. Sci., 13:185, 1923 (type
locality, Plomosas, Sinaloa).
Remarks.—Specimens of Sceloporus nelsoni from the region near
Mazatlan are lighter in color than those elsewhere (Cochran,
1923:186). Smith (1939c:367) commented that females from this
area "have much less ventral maculation on the throat, breast, and
sides of abdomen, than females from elsewhere, and males have
less maculation on the chest." However, Smith did not consider
these differences sufficient to warrant subspecific recognition.
Tanner and Robison (1959:79) using ten specimens from Urique,
Chihuahua, described the subspecies Sceloporus nelsoni coeruleus
( — S. n. barrancorum, Tanner and Robison, 1960:114). They
diagnosed barrancorum, in part, as being smaller than nelsoni, as
having more dorsals and fewer postrostrals (three), and the males
as having extensive deep blue from throat to hind legs.
Analysis of five characters for 16 specimens from Chihuahua and
56 specimens from Sinaloa (Table 4) fails to support the conclusions
reached by Tanner and Robison, except that the maximum
snout-vent length is slighUy smaller in Chihuahua and northern
Sinaloa than in southern Sinaloa. Additional material and localities
may reveal clinal variation with respect to certain of these characters.
The color pattern of the chest and belly of males is the
most conspicuous variable. In specimens from Chihuahua and
Choix, Sinaloa, (KU 73728) the chest and belly are solid black
or very deep blue. The chest and belly are deep blue in male
lizards from El Fuerte (KU 78669-75). A male (LACM 6682)
from Terreros has the belly nearly all blue, darker midventrally;
the chest is spotted with blue scales on white. A male from near
Badiraguato (KU 83400) has black-edged, blue belly patches separated
by a white median line that is continuous with a white
chest. In the two specimens from south of Culiacdn (KU 37773,
44850) the belly is blue laterally, darker blue medially, and the
chest is white with large irregular blue blotches, similar to the
Terreros specimen. Lizards from San Ignacio and vicinity (KU
73730-31, 78678-79; LACM 6675-77, 6679, 6681) have blue belly
patches edged with black medially and posteriorly. The belly
patches are in contact medially about two-thirds of their length,
with white indentations anterior and posterior. The chests of these
males are either all white, speckled blue and white, or blue-black
with three or four white blotches. Males from vicinity of Mazatlan