Palaeosaniwa
Encyclopedia
Palaeosaniwa is an extinct genus
of varanoid lizard
from the late Cretaceous
of North America. The name, given by Charles Whitney Gilmore in 1928, means "ancient Saniwa
."
) in size, and perhaps measuring five to six feet in length, which would make it one of the largest terrestrial lizards known from the Mesozoic. It resembles varanids in having bladelike teeth bearing minute serrations, which suggests a similar lifestyle as a predator of other vertebrates. Palaeosaniwa is known from the late Campanian of Alberta, Canada, and from the late Maastrichtian of Wyoming and Montana. Originally, Palaeosaniwa was thought to be closely related to the varanids, but more recently it has been interpreted as a relative of the Helodermatidae, the group including Gila monster
s and Beaded lizard
s. It has also been suggested that it was venomous.
Genus
In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...
of varanoid lizard
Lizard
Lizards are a widespread group of squamate reptiles, with nearly 3800 species, ranging across all continents except Antarctica as well as most oceanic island chains...
from the late Cretaceous
Late Cretaceous
The Late Cretaceous is the younger of two epochs into which the Cretaceous period is divided in the geologic timescale. Rock strata from this epoch form the Upper Cretaceous series...
of North America. The name, given by Charles Whitney Gilmore in 1928, means "ancient Saniwa
Saniwa
Saniwa is an extinct genus of monitor lizard that lived during the Eocene epoch around 48 million years ago. Well-preserved fossils have been found in the Bridger and Green River Formations of Wyoming, and there is evidence that Saniwa also lived in Europe. The type species S. ensidens was named in...
."
Description
Palaeosaniwa is a large carnivorous lizard, comparable to a large monitor lizard (VaranidaeVaranidae
Varanidae is a group of lizards of the superfamily Varanoidea. The family is a group of carnivorous lizards which includes the largest living lizard, the Komodo dragon, and the crocodile monitor. Varanidae contains the living genus Varanus and a number of extinct taxa...
) in size, and perhaps measuring five to six feet in length, which would make it one of the largest terrestrial lizards known from the Mesozoic. It resembles varanids in having bladelike teeth bearing minute serrations, which suggests a similar lifestyle as a predator of other vertebrates. Palaeosaniwa is known from the late Campanian of Alberta, Canada, and from the late Maastrichtian of Wyoming and Montana. Originally, Palaeosaniwa was thought to be closely related to the varanids, but more recently it has been interpreted as a relative of the Helodermatidae, the group including Gila monster
Gila monster
The Gila monster is a species of venomous lizard native to the southwestern United States and northwestern Mexican state of Sonora...
s and Beaded lizard
Beaded lizard
The Beaded lizard is a species of venomous lizard found principally in Mexico and southern Guatemala. Along with its congener, the Gila monster , it is the only lizard to have evolved an overt venom delivery system, and has long been considered the only venomous lizard...
s. It has also been suggested that it was venomous.