Tantilla yaquia
YAQUI BLACK-HEADED SNAKE
Tantilla yaquia - Smith 1942
IDENTIFICATION:
DISTRIBUTION:
Generally, Tantilla yaquia occurs from the Arizona border south through Sonora, the Río Fuerte drainage of extreme southwestern Chihuahua, Sinaloa and terminates at the valley of the Río Santiago in southern Nayarit, Mexico. The possibility also exists that this species occurs in the foothills of the Sierra Madre Occidental in extreme western Durango.
HABITAT:
This species is found in a variety of habitats over a relatively broad elevational range. In Arizona and northern Sonora, Mexico its distribution is largely Madrean Oak Woodland at elevations greater than 1,000 m. In southern Sonora, Sinaloa and Nayarit it inhabits seasonally dry Tropical Thornscrub and Tropical Deciduous Forest from near sea-level to around 800 m. Most specimens are found in the vicinity of streambeds, arroyos and other topographically diverse environs.
NATURAL HISTORY:
The Yaqui Black-Headed Snake, like other Tantilla, is secretive and rarely seen abroad. Most individuals are found beneath surface cover after periods of rain (especially in the winter and spring). In the summer this species becomes nocturnal and may be found foraging on the surface. T. yaquia feeds on invertebrates, primarily arachnids and small species of centipedes. In turn, it is preyed upon by tarantulas of the genera Aphonopelma and Brachypelma as well as large species of centipedes such as Scolopendra heros. One specimen (MVZ 59778) was recovered from the stomach of a Tarahumara Frog (Rana tarahumarae). T. yaquia lays eggs from March-April; it has never been found to occur in sympatry with another member of the genus Tantilla.
TAXONOMY:
Tantilla yaquia is considered a part of the Tantilla planiceps species group. It is closely allied to T. atriceps, T. planiceps, T. hobartsmithi, T. wilcoxi and T. bocourti.
Synonomies include Tantilla bogerti, originally described by N. Hartweg (1944) from Acaponeta, Nayarit.
TYPE:
Described as Tantilla yaquia by Smith (1942). Holotype: MCZ 43274. Type locality: Guasaremos, Chihuahua, Mexico. Specimen collected by H. S. Gentry.
PERSONAL NOTES:
I have seen this species only once; in August 2002 we found an individual crossing the highway west of Alamos, Sonora at around 04:00 hours. The habitat at this site was thornscrub and seasonally dry tropical diciduous forest transition.
CONSERVATION STATUS:
Tantilla yaquia is a common and widely-distributed species; it exists in human-modified habitats and is no danger of local or wide-scale population declines.
REFERENCES:
Hartweg, N. 1944. Remarks on some Mexican Snakes of the Genus Tantilla. Occasional Papers of the Museum of Zoology of the University of Michigan 486:1-9.
McDiarmid, R. W. 1968. Variation, Distribution and Systematic Status of the Black-Headed Snake Tantilla yaquia Smith. Bulletin of the Southern California Academy of Sciences 67(3):159-177.