| Mosasaurins | |
|---|---|
 | |
| Skeleton ofMosasaurus (front view) in theMaastricht Natural History Museum. | |
Scientific classification | |
| Domain: | Eukaryota |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Reptilia |
| Order: | Squamata |
| Clade: | †Mosasauria |
| Family: | †Mosasauridae |
| Subfamily: | †Mosasaurinae |
| Tribe: | †Mosasaurini Russell, 1967 |
| Genera | |
| Synonyms | |
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Mosasaurini is an extincttribe ofmosasaurinemosasaurs who lived during theLate Cretaceous and whose fossils have been found inNorth America,South America,Europe,Africa andOceania, with questionable occurrences inAsia. They are highly derived mosasaurs, containing genera likePlotosaurus, having unique adaptations to fast swimming speeds, orMosasaurus, which is among the largest knownmarine reptiles.
The tribe was erected byRussell in 1967, stating that it is unified by having twelve or less pygalvertebrae and that theradius andulna are widely separated by a bridge ofcarpalia on the distal border of the antebrachialforamen.[1] But In a 1997 study, paleontologist Gorden Bell recoveredPlotosaurus, which was formerly classified within another tribe called the Plotosaurini, as asister genus toMosasaurus. This rendered the Mosasauriniparaphyletic, which meant that it now contains a descendant lineage (Plotosaurini) that is not classified under it, and made its definition defunct.[2] Paraphylies are forbidden incladistics and so scientists must reclassify groups in order to eliminate such discrepancies if possible.[3] 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 containingMosasaurus should bemonophyletic, 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carrying over to all ranks in a classification hierarchy, and that the original diagnostics of the Plotosaurini is outdated.[4]
The taxa Mosasaurini has historically been more inclusive, on occasion including genera such asPlesiotylosaurus,[5]Liodon andClidastes,[1] all of which are now seen as more basal mosasaurines.[6]
A more recently suggested definition is a branch-based definition diagnosing the Mosasaurini as the most inclusive clade containingMosasaurus hoffmannii but notGlobidens dakotensis.[7]
