Mosasaurini
The Mosasaurini are a tribe of mosasaurine mosasaurs, a diverse group of Late Cretaceous marine squamates. Members of the tribe, known as "mosasaurins", have been recovered from North America, South America, Europe, Africa and Oceania, with questionable occurrences in Asia. The tribe contains the closely related genera "Mosasaurus", "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 fast swimming speeds and "Mosasaurus" itself, among  the largest of the mosasaurs. The etymology of the tribe derives from the genus "Mosasaurus" (Latin "Mosa" = "Meuse river" + Greek "sauros" = "lizard"). Description. The Mosasaurini are a clade of derived mosasaurine mosasaurs. The tribe contains one of the largest known mosasaur species, "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 (such as "Plotosaurus", "Eremiasaurus" and "Mosasaurus conodon") whilst others are even smaller in a  range of about 5–6 meters in length (such as "Mosasaurus beaugei" and "Mosasaurus missouriensis"). The tribe was erected by Russell (1967), stating that it is 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. But In a 1997 study, paleontologist Gorden Bell recovered "Plotosaurus", which was formerly classified within another tribe called the Plotosaurini, as a sister genus to "Mosasaurus". This rendered the Mosasaurini paraphyletic, which meant that it now contains a descendant lineage (Plotosaurini) that is not classified  under it, and made its definition defunct. Paraphylys are forbidden in cladistics and so scientists must reclassify groups in order to eliminate such discrepancies if possible. Bell proposed that the Mosasaurini should be abandoned and that all members of the tribe should be incorporated into the Plotosaurini. While other scientists agree that a tribe containing "Mosasaurus" should be monophyletic, they argue that Mosasaurini should be the valid tribe. For example, in a 2012 study, Aaron LeBlanc, Caldwell, and Bardet argued that, while it is not necessarily invalid, abandoning Mosasaurini would not follow the general principle of the type genus carrying  over to all ranks in a classification hierarchy, and that the original diagnostics of the Plotosaurini is outdated. 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". Species and taxonomy. Mosasaurini