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

AMPHIBIANS AND REPTILES OF SINALOA, MEXICO 205
the correct name by priority for T. cyrtopsis. However, according
to Webb (1966:56), the name dorsalis probably belongs to the upper
Rio Grande population of Thamnophis sirtalis and would replace
T. sirtalis ornata Baird. This would allow conservation of the name
cyrtopsis for the snakes as understood by Smith (1951). Webb
also stated (pp. 60-63} that Tropidonotus cdllaris Jan, 1863, is the
earliest name for the population of cyrtopsis in the coastal lowlands
and subtropical highlands of western Mexico [Sinaloa]. Therefore,
the Sinaloan population of black-necked garter snakes should be
known as Thamnophis cyrtopsis cdllaris, one of five subspecies of
cyrtopsis listed by Webb (p. 69). The other subspecies are T. c.
cyrtopsis in the southwestern United States and Mexican plateau,
T. c. ocellata in central Texas, T. c. postremus in Michoacan, and
T. c. pulchrilatus in highland areas from Durango to Morelos and
Veracruz.
Thamnophis has been collected in a variety of habitats in the
state: along irrigation ditches near Los Modus, in forest near
Culiacan, and along rivers near Presidio. The species has successfully
occupied the extensive agricultural areas of the Rio Fuerte
floodplain.
Distribution in Sinaloa.—Throughout the state from near sea
level to about 2000 meters. See Fig. 85.
Specimens examined.—N edge Culiacan (CSCLB 1939); 4.7 mi. N Culiacan
(CSCLB 1970); 23 km. N Culiacan (CSCLB 1945); 68.7 N Culiacan (LACM
7173); 4.2 mi. S Culiacan (LACM 7183); 5.5 mi. S Culiacan (LACM 7178);
6.7 mi. S Culiacan (LACM 7179); 6.9 mi. S Culiacan (LACM 7180); 17 km.
S Culiacan {CSCLB 1944); 15 mi. S Culiacan (LACM 25936-37); 16.9 mi.
S Culiacan (LACM 7181); 19 mi. S Culiacan (LACM 25935); 22 mi. S
Culiacan (LACM 25934); 5 km. SW El Palmito, 1900 m. (• KU 75632-33,
80761); 8 mi. W El Palmito (LACM 25198-99); 8 mi. N Guamuchil (CSCLB
1940); 3.8 mi. N La Cruz turnoff, hwy. 15 (LACM 7172); 5.6 mi. E La Cruz
(LACM 7174); 1.2 mi. N Los Mochis (CSCLB 1941); 47 km. N Los Mochis
("KU 67725); 2-3 mi. S Los Mochis (UCLA 12513); 7.3 mi. S Los Mochis
(UAZ 9373-77); 13.6 mi. S Los Mochis tumoff, hwy. 15 (LACM 7177);
3.3 mi. SW Los Mochis (JFC 63:147); 5.3 mi. SW Los Mochis (JFC 63:148);
15 mi. S Mazatlan. Rio Presidio (SU 18261-62); San lose del Oro, 230 m.
( e KU 83413); 1 km. NE Santa Lucia (CSCLB 1942); 2.2 km. NE Santa
Lucia, 1155 m, (°KU 78923-24); 19.2 km. NE Santa Lucia, 1935 m. ("KU
78925-29); 1.5 km. E Santa Lucia, 1700 m. (" KU 40349); 4.1 mi. N Terreros
(LACM 7176); 0.7 mi. S Terreros (LACM 7184); 15.7 mi. S Terreros (LACM
7175).
Literature records.—Copala (Wehb, 1966:63); Costa Rica (Smith and Van
Gelder, 1955:147; Webh, 1966:63); El Batel, 70 km. NE Mazatlan (Webb,
1966:63); El Dorado (Fugler and Dbon, 1961:16; Webb, 1966:63); 1 mi.
NE El Fuerte; 8 mi. W El Palmito (Webb, 1966:63); 6.6 mi. S Guasave
(Fouquette and Rossman, 1963:197); 70 km. NE Mazatlan (Milstead, 1953:
372); Rosario (Smith, 19426:108 and 1943a:479; Webb, 1966:63); 1 mi. E
Santa Lucia (Webb, 1966:63).
Additional records.—4.8 mi. N Culiacan (FAS 11364); 26.7 mi. N Culiacan
(FAS 11353); 44.6 mi. N Culiacan (FAS 17013); 44.8 mi. N Culiacan (FAS