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

AMPHIBIANS AND REPTILES OF SINALOA, MEXICO 159
are distinctly black edged, more pronounced laterally than middorsally.
On the anterior and posterior part of the body the black
edging of the dorsal scales can be made visible by spreading the
scales. The supralabials are lightly mottled with gray and there is
no distinct ocular stripe. In other characters, this specimen agrees
with the original description (Smith, 1943a:418).
This is the first record of the species in Sinaloa. The specimen
was taken in tropical dry forest (Plate 7, Fig. 1).
Distribution in Sinaloa.—Known only from the southern lowlands,
in the vicinity of Villa Union. See Fig. 61.
Specimen examined.—% km. N Villa Uni6n, 140 m. (• KU 80746).
Additional record.—15 mi. SE Escuinapa (UMMZ 118784).
Drymarchon corais rabidus Smith
Drymarchon corais rabidus Smith, Jour. Washington Acad. Sci., 31:474,
November 11, 1941 (type locality, Rosario, Sinaloa).
Remarks.—Duellman (1961:93-94) reported specimens of Drymarchon
corais rabidus from Michoacan that deviate from the uniform
black dorsal coloration reported by Smith (1941d:475) by being
either pale brown anteriorly with black flecks arranged as narrow
transverse bands, or black above with reddish or "rust-colored" crossbands
on the anterior half of the body. Eight of the 19 specimens
at hand have a pale brown dorsal coloration anteriorly that is either
mottled or flecked with black; the amount of black increases progressively
to the tail, which is uniformly black above. One specimen
(LACM 6801) is reddish brown dorsally with black flecks on the
anterior half of body; the flecks form bars near midbody; the
posterior quarter of the snake is black. Another specimen (LACM
6802) is black with reddish, chevron-shaped cross bands on the
anterior half of body. Scott (1962:46) reported snakes of glossy,
jet black; dull grayish black, often with a red tint; and one or two
dull, brick-red specimens. The ventral coloration varies from
coral-red to white to gray anteriorly; the caudal coloration is dark
gray or black. The geographical variation in coloration of Drymarchon,
as pointed out by Duellman (1961:94) and supported by
our data, points to a need for re-evaluation of the subspecific status
of certain populations of Drymarchon and for a re-examination of
the alleged intergrades (Smith, 1941d:476-77).
Smith (1941d:475) reported the range of ventrals for this subspecies
as 190-203, and the range of subcaudals as 69-78. Seventeen
specimens examined have 187-197 (190.1) ventrals (excluding KU
73492-93), and nine specimens have 59-73 (66.6) subcaudals. The