Beaded lizard, Heloderma horridum "Just let me sleep!" by Chester Zoo via Flickr, Creative Commons Attribution-NoDerivs.

Gila monster, Heloderma suspectum "11F242 Gila Monster 001 at Taronga Zoo Sydney" by PG Palmer (AU) via Flickr, Creative Commons Attribution ShareAlike.

Taxonomy:

Beaded lizard, Heloderma horridum

Heloderma horridum alvarezi (Add)
Heloderma horridum charlesbogerti (Add)
Heloderma horridum exasperatum (Add)
Mexican Beaded Lizard, Heloderma horridum horridum (Add)

Gila monster, Heloderma suspectum

Heloderma suspectum cinctum (Add)
Heloderma suspectum suspectum (Add)