The black-tailed rattlesnake is a venomous pit viper species found in the southwestern United States and Mexico. Four subspecies are currently recognized, including the nominate subspecies described here.
Crotalus basiliscus, known as the Mexican west coast rattlesnake, Mexican green rattler, and also by other names, is a species of pit viper in the family Viperidae. The species is endemic to western Mexico. Like all other pit vipers, it is venomous. The specific name, basiliscus, is derived from the Greek word for king, βασιλισκος, and alludes to this snake's large size and potent venom. No subspecies are currently recognized.
Crotalus helleri or Crotalus oreganus helleri, also known commonly as the Southern Pacific rattlesnake, the black diamond rattlesnake, and by several other common names, is a pit viper species or subspecies found in southwestern California and south into Baja California, Mexico, that is known for its regional variety of dangerous venom types. It is sometimes considered a subspecies of Crotalus oreganus.
Crotalus willardi is a venomous pit viper species found in the southwestern United States and Mexico. This snake is found mainly in the "sky island" region. The IUCN reports this snake's conservation status as being of Least Concern. It is the official state reptile of Arizona.
Crotalus ruber is a venomous pit viper species found in southwestern California in the United States and Baja California in Mexico. Three subspecies are currently recognized, including the nominate subspecies described here.
Crotalus mitchellii is a venomous pit viper species in the family Viperidae. The species is endemic to the Southwestern United States and adjacent northern Mexico. The species was named in honor of Silas Weir Mitchell (1829–1914), an American medical doctor who also studied rattlesnake venoms. Five subspecies are currently recognized, including the nominate subspecies described here.
Crotalus viridis nuntius is a venomous pit viper subspecies native primarily to the desert plateau of the northeastern portion of the American state of Arizona, but also ranges into northwestern New Mexico. Named for the Native American Hopi tribe, which inhabits the region, its range overlaps that of the nominate subspecies and some interbreeding is believed to occur. The taxonomy of the C. viridis group is a matter of debate, many considering the various subspecies to be nothing more than locality variations.
Crotalus durissus, known as the South American rattlesnake, tropical rattlesnake, and by other names, is a highly venomous pit viper species found in South America. It is the most widely distributed member of its genus. Currently, seven subspecies are recognized.
Crotalus simus is a venomous pit viper species found in Mexico and Central America. The specific epithet is Latin for "flat-nosed", likely because its head is blunt compared with lanceheads (Bothrops). Three subspecies are recognized, including the nominate subspecies described here.
Crotalus oreganus, commonly known as the Western rattlesnake or northern Pacific rattlesnake, is a venomous pit viper species found in western North America from the Baja California Peninsula to the southern interior of British Columbia.
Crotalus atrox tortugensis is a venomous pit viper subspecies found only on Tortuga Island in the Gulf of California.
The Great Basin rattlesnake is a venomous pit viper species found in the Great Basin region of the United States.
Crotalus pricei is a species of venomous snake, a pit viper in the family Viperidae. The species is endemic to the southwestern United States and northern Mexico. Two subspecies are recognized.
Crotalus cerberus is a venomous pit viper species found in the southwestern United States. It is known as the Arizona black rattlesnake, black rattlesnake, and several other common names.
Crotalus willardi obscurus is a venomous pitviper subspecies found in northwestern Mexico and the Southwestern United States.
Crotalus totonacus is a venomous pit viper species found in northeastern Mexico. No subspecies are currently recognized.
Crotalus angelensis, or the Ángel de la Guarda Island speckled rattlesnake, is a pitviper species endemic to Isla Ángel de la Guarda in the Gulf of California, Mexico. Like all other pitvipers, it is venomous. It is sometimes treated as a subspecies of Crotalus mitchellii.
Crotalus oreganus caliginis is a venomous pit viper subspecies endemic to South Coronado Island, Mexico.
Crotalus lorenzoensis is a species of pit viper.
Crotalus mitchellii muertensis is a venomous pitviper subspecies endemic to El Muerto Island, Mexico. It is sometimes treated as a full species, Crotalus muertensis.
