Mexican beaded lizard generic name "Heloderma" means "studded skin", from the Ancient Greek words "hêlos" (ἧλος)—the head of a nail or stud—and "dérma" (δέρμα), meaning skin. Its specific name, "horrĭdum", is the Latin word meaning rough or rude. The four subspecies of beaded lizard, elevated to full species in 2013, are: Adult beaded lizards range from in length. They are substantially larger than the Gila monster, which only reaches lengths of . The snout-to-vent length of a beaded lizard averages . The average body mass of an adult beaded lizard is , about 45% heavier than the average mass of a gila monster,
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