Named By: S. W. Shannon & K. R. Wright - 1988.
Classification: Chordata, Reptilia, Squamata, Mosasauridae, Plioplatecarpinae.
Species: S. russelli (type), S. johnsoni.
Known locations: USA, Alabama - Mooreville Chalk Formation, Kansas - Niobrara Formation.
Time period: Santonian to Campanian of the Cretaceous.
Fossil representation: At least two individuals but mostly of skull material.
is unusual amongst mosasaurs because it has an akinetic skull, which
means that its jaws were incapable of widening to swallow larger prey.
This strongly suggests that Selmasaurus restricted
itself to small
prey species that were easily swallowed. This would infer behaviour
similar to other plioplatecarpine mosasaurs such as Platecarpus
that are thought to have been more active predators of
fish. However it is still uncertain if Selmasaurus
had a tail fluke
like the aforementioned Platecarpus.
One interesting bit of trivia about Selmasaurus is that although it was officially named in 1988, it was actually unofficially named back in 1975 as part of a masters thesis by Samuel Wayne Shannon.