Long known to Filipino tribal hunters, the monitor lizard was identified as a new species in 2009 via its DNA, scale pattern, size, and peculiar penis, a new study says.

At about six and a half feet (two meters) long, the new lizard species is closely related to the world's largest living lizard, the Komodo dragon. Unlike the Komodo, though, Varanus bitatawa has evolved to be a vegetarian.

(Related: "New Fossil Is World's Oldest Plant-Eating Lizard.")

The lizard discovery "comes as an unprecedented surprise," not least because V. bitatawa's home island of Luzon is "heavily populated and highly deforested," the study authors write in Wednesday's issue of the journal Biology Letters.

(Also see "New Giant Lizard: Komodo Cousin 'A Nasty