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

AMPHIBIANS AND REPTILES OF SINALOA, MEXICO 131
1 1 1 1 1 1 1 1 1 1—
VACA
12 C3^E^^m5EE3-
EL FUERTE 32
CULIACAN 14
MAZATLAN
17 C
CONCEPCION 13
28 30 32 34 36
FIG. 9. Variation in the number of dorsal scales in five samples of Scehporus
clarkii boulengeri in Sinaloa. The horizontal line represents the range of variation;
the vertical line, the mean; the solid rectangle, two standard errors on
either side of the mean; open rectangle, two standard deviations on either side
of the mean. The samples include both sexes.
the lorilabials, only one scale between the subocular and labials,
only four supraoculars, and postmentals reduced to four. Tanner
and Robison also stated that the Urique specimens do not have the
dorsolateral stripes characteristic of boulengeri.
Three male topotypes (KU 56215-17), examined by us, have the
nasal in contact with the lorilabials in one and not in two; they have
2, 3, and 2/1 rows of lorilabials between subocular and labials; two
specimens have 5 supraoculars, one has six (or at least five, depending
on whether small anterior plates are counted). The postmentals
were counted in the manner indicated by Smith (1946:180)
and Peters (1964:274). The three topotypes and 135 (of 139)
Sinaloan specimens have two postmentals. Four specimens representing
four different localities from El Fuerte to Rosario have three
postmentals. Tanner and Robison evidently counted postmentals
in the manner indicated by Smith (1939c:23). In any case, our
data show no decrease in northern Sinaloa or at Urique; of 140
specimens examined only nine have a reduction of supraoculars