Saniwa is an extinct genus of varanid lizard that lived during the Eocene epoch. It is known from well-preserved fossils found in the Bridger and Green River Formations of Wyoming, United States. The type species S. ensidens was described in 1870 as the first fossil lizard known from North America. A second species, S. orsmaelensis, is recognised from remains found in Europe. It is a close relative of Varanus, the genus that includes monitor lizards.
Saniwa
The skull of S. ensidens
Leidy's illustrations of the humerus of S. major and the vertebrae of S. ensidens
The vertebrae and limb bones of the holotype specimen of S. ensidens
The Varanidae are a family of lizards in the superfamily Varanoidea and order Anguimorpha. The family, a group of carnivorous and frugivorous lizards, includes the living genus Varanus and a number of extinct genera more closely related to Varanus than to the earless monitor lizard (Lanthanotus). Varanus includes the Komodo dragon, crocodile monitor, savannah monitor, the goannas of Australia and Southeast Asia, and various other species with a similarly distinctive appearance. Their closest living relatives are the earless monitor lizard and Chinese crocodile lizard. The oldest members of the family are known from the Late Cretaceous of Mongolia.
Image: Komodo dragons (Varanus komodoensis) fighting
Image: Saniwa FMNH
Gray's monitor (Varanus olivaceus) is a tree-dwelling varanid from the Philippines that primarily feeds on fruit
