Named By: Nathalie Bardet, Xabier Pereda Suberbiola & Nour-Eddine Jalil - 2003.
Classification: Chordata, Reptilia, Squamata, Mosasauridae, Russellosaurinae.
Species: T. nopscai (type).
Size: 3 meters long.
Known locations: Morocco, Errachidia Province.
Time period: Early Turonian of the Cretaceous.
Fossil representation: Skull and almost complete post cranial skeleton.
is a primitive (basal) mosasaur that is considered to be related to
from North America and Yaguarasaurus
from South America.
Like these other two mosasaurs, Tethysaurus has
a mixture of both
primitive and advanced features that make it a primitive relative
to other later mosasaur groups, although not as primitive as
which is thought to be one the most primitive mosasaurs
Tethysaurus was named after Tethys, the ancient Greek goddess of the sea who was also the inspiration for the name of the Tethys Ocean that once separated Laurasia (the northern continents) from Gondwana (the southern continents). The species name, T. nopscai, is in honour of the Hungarian palaeontologist Baron Ferenc Nopsca.