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

AMPHIBIANS AND REPTILES OF SINALOA, MEXICO 155
reported a specimen of L. h. dugesii from 45.1 miles south of Santa
Ana, Sonora; it has 5 pigmented dorsal rows, suggestive of intergradation
with L. h. cahuilae rather than L. h. humilis. They further
point out that the central Sonoran population possibly is distinct
from both humilis and dugesii. Fugler and Dixon (1961:12)
obtained one specimen of L. h. dugesii from El Dorado, Sinaloa.
Three specimens examined have 14 rows of scales around body;
12 rows of scales around tail; 255, 255, 248 middorsal scales from
rostral to tail spine. The seven median dorsal scale rows and half
of each adjacent lateral scale row are brown; the remaining rows
lack pigmentation. One specimen, a male, (KU 95951), has a
snout-vent length of 307 and a tail length of 14. Our specimens
confirm Klauber's contention (1940:131) that dorsal scales increase
from south to north along the Pacific coast of Mexico. Two individuals
(LACM 6772, 6773) were found at night on the road
following a heavy rain.
Distribution in Sinaloa.—Probably occurs throughout the lowlands
of the state. See Fig. 58,
Specimens examined.—11 mi, N Culiacan (* LACM 6772); El Salado, 300
ft (*KU 95951); 0.5 mi. N Terreros ("LACM 6773).
Literature records.—El Dorado (Fugler and Dixon, 1961:12); Mazatlan;
Presidio (Klauber, 1940:131; Smith and Taylor, 1945:21).
Additional records.—11.4 mi. S Agua Caliente (UF 12790); 5.6 mi. N
Culiacan (UMMZ 120228); El Dorado (AMNH 90760-64).
Family Boidae
Boa constrictor imperator Daudin
Boa imperator Daudin, Hist. Nat., . . . des reptiles, 5:150, 1803 (type
locality, Mexico).
Boa constrictor imperator: Forcart, Herpetologica, 7:199, December 31,
1951.
Remarks.—Four specimens have 66, 71, 70, 74 dorsal scales at
midbody, 245, 233, 239, 242 ventrals, and 53, 61, 57, 60 subcaudals.
During the summer of 1962 more than 150 specimens of this
ubiquitous species were collected but, because of the abundance
and size of the species, only a few were preserved. Boas are more
abundant in the southern part of the state. The snake is primarily
nocturnal and most individuals were encountered on the road at
night between 1930 and 2400 hours, when air temperatures ranged
from 22° to 29°C. A few were taken in the dry season, but the
snakes are most common during the rainy season.
Two boas approximately 1200 mm. in length were reported mating
near Teacapan on April 6 (Scott, 1962:31). A female about 1200