1) Family helodermatidae 2) Only known venomous lizards 3) Reptile family 
Helodermatidae is the venomous lizards family of reptiles of the super family Varanoidea, suborder Anguinomorpha, order Squamata. The family is represented by a single genus, Heloderma (the Gila Monster and Beaded Lizard), and two species found in North America, mainly Mexico.
[n] - only known venomous lizards
family Helodermatidae noun only known venomous lizards