I'm familiar with five known groups of mosasaurs: tethysaurines, yaguarasaurines, tylosaurines, mosasaurines, and plioplatecarpines. However, all those groups of mosasaurs look superficially similar to each other with very little variation in the postcranial region. Is there any features that would distinguish tylosaurines, plioplatecarpines, mosasaurines, tethysaurines, and yaguarasaurines from each other?