The Mosasaurini are a tribe of mosasaurinemosasaurs, a diverse group of Late Cretaceousmarinesquamates. Members of the tribe, known as "mosasaurins", have been recovered from North America, Europe, Africa and Oceania, with questionable occurrences in Asia. The tribe contains the closely related generaMosasaurus, Eremiasaurus, Plotosaurus and Moanasaurus. It has historically been more inclusive, on occasion including genera such as Plesiotylosaurus, Liodon and Clidastes, all of which are now seen as more basal mosasaurines. Mosasaurins were highly derived predatory mosasaurs, containing genera like Plotosaurus, with unique adaptations towards fastswimming speeds and Mosasaurus itself, among the largest of the mosasaurs. The etymology of the tribe derives from the genus Mosasaurus.
Description
The Mosasaurini are a clade of derived mosasaurine mosasaurs. The tribe contains one of the largest known mosasaurspecies, Mosasaurus hoffmannii at over 12 meters in length, but it is notable that such a size is unusual within the tribe and even within the genus Mosasaurus itself. Other large mosasaurins are in a size range around 8 meters in length whilst others are even smaller in a range of about 5–6 meters in length. Russell stated that the Mosasaurini are unified by having twelve or less pygal vertebrae and that the radius and ulna are widely separated by a bridge of carpalia on the distal border of the antebrachial foramen. With Plotosaurus being referred to the Mosasaurini, this definition becomes defunct as Plotosaurus has more than twelve pygal vertebrae and its radius and ulna only nearly contacting above the carpalia on the distal border of the antebrachial foramen. Russell thus considered Plotosaurus as being part of its own tribe, the "Plotosaurini" together with the tylosaurineTaniwhasaurus, but this is not supported in modern analyses. A more recently suggested definition is a branch-based definition diagnosing the Mosasaurini as the most inclusive clade containing Mosasaurus hoffmannii but not Globidens dakotensis.
