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,
The Lizard main units; the serpentinites, the "oceanic complex" and the metamorphic basement. Several nature sites exist on the Lizard Peninsula; Predannack nature reserve, Mullion Island, Goonhilly Downs, and the Cornish Seal Sanctuary at Gweek. An area of the Lizard covering is designated a national nature reserve because of its coastal grasslands and heaths and inland heaths. The peninsula contains 3 main Sites of Special Scientific Interest (SSSI), both noted for their endangered insects and plants, as well as their geology. The first is East Lizard Heathlands SSSI, the second is "Caerthillian to Kennack SSSI" and the third is West Lizard SSSI,