Palaeosaniwa

Palaeosaniwa is an extinct genus of carnivorous lizard from the Late Cretaceous of North America. The type (and only) species, Palaeosaniwa canadensis, given by Charles Whitney Gilmore in 1928, means "ancient Saniwa from Canada".

Palaeosaniwa is an extinct genus of carnivorous lizard from the Late Cretaceous of North America. The type (and only) species, Palaeosaniwa canadensis, given by Charles Whitney Gilmore in 1928, means "ancient Saniwa from Canada".

Distribution

Palaeosaniwa was originally described from the late Campanian of Alberta. More recently it has been reported from the late Campanian of Montana, and the late Maastrichtian of Montana and Wyoming. It is known primarily from isolated teeth and vertebrae, but two partial skeletons have also been discovered. The type species, P. canadensis, is from Alberta. Although the Maastrichtian Palaeosaniwa has traditionally been referred to this species, it succeeds it by roughly ten million years. Given the distance in time between these animals, they are likely to represent distinct species, but the available fossils are too incomplete to be certain.

Relationships

Palaeosaniwa is a member of the Platynota, a group that includes the monitor lizards (Varanidae) and Gila monsters (Helodermatidae). Originally, it was thought to be a member of the Varanidae, but has also been interpreted as a relative of the Helodermatidae. The most recent analysis places Palaeosaniwa outside of either Varanidae or Helodermatidae, as a stem member of the Varanoidea. Its precise affinities remain poorly understood, but it may be related to other Late Cretaceous, North American carnivorous lizards such as Parasaniwa, Paraderma, Labrodioctes, and Cemeterius.

Text derived from https://en.wikipedia.org/w/index.php?oldid=1374970238 under CC BY-SA 4.0; modifications have been made.