Mexican beaded lizard Mexican beaded lizard The Mexican beaded lizard ("Heloderma horridum") is a species of lizard in the family Helodermatidae, one of the two species of venomous beaded lizards found principally in Mexico and southern Guatemala. It and its congener (member of the same genus) the Gila monster ("Heloderma suspectum") are the only lizards known to have evolved an overt venom delivery system. The Mexican beaded lizard is larger than the Gila monster, with duller coloration, black with yellowish bands. As it is a specialized predator that feeds primarily upon eggs, the primary use of its venom is still a source of
Banded rock lizard Banded rock lizard The banded rock lizard ("Petrosaurus mearnsi" ) is a species of lizard in the family Phrynosomatidae. The species is native to western North America. The specific name, "mearnsi", is in honor of American naturalist Edgar Alexander Mearns, who collected the first specimens. "P. mearnsi" is endemic to extreme southern California and Baja California, Mexico. It also occurs on Isla El Muerto. "P. mearnsi" is an extremely flat-bodied lizard. Its dorsum is olive, brown or gray, with white or bluish spots. It has a single black collar, a banded tail, and granular scales on its body, with keeled