A New Subspecies of Beaded Lizard, Heloderma horridum, from the Motagua Valley of Guatemala

Abstract

A new subspecies of beaded lizard, Heloderma horridum charlesbogerti is described from the xeric middle Motagua Valley of eastern Guatemala. It differs from the other subspecies of H. horridum in scalation, body proportions, coloration, and pattern. The Motagua population of H. horridum is widely disjunct from other conspecific populations. The probable vicariance event that shaped present distribution of the Motagua Valley population was the formation of the volcanic cordillera in southern Guatemala during the Quaternary. With the formation of this chain of high mountains, the Pacific coast and piedmont of Guatemala became more mesic, fragmenting Heloderma populations and restricting H. horridum to the east and west in drier habitats.