Metriorhynchoid crocodylians represent the pinnacle of marine specialization within Archosauria. Not only were a major component of the Middle Jurassic–Early Cretaceous marine ecosystems, but they provide further that extinct crocodilians did not all resemble their modern extant relatives. Here, we use a varied toolkit techniques, including phylogenetic reconstruction, geometric morphometrics, diversity counts, discrete character analysis, and biomechanical finite-element analysis (FEA), to examine the macroevolutionary history of clade. All analyses demonstrate that this clade became more divergent, in terms of biodiversity, form, and , up until the Jurassic–Cretaceous boundary, after which there is no evidence for recovery or further . A clear evolutionary trend towards hypercarnivory in Dakosaurus is supported by phylogenetic optimization, morphometrics, and FEA, which also support specialized piscivory within Rhacheosaurus Cricosaurus. Within Metriorhynchoidea, there is a consistent trend towards increasing marine specialization, the hypermarine Cricosaurus exhibiting numerous convergences with other Mesozoic marine reptiles (e.g. loss the deltopectoral crest and retracted external nares). In addition, biomechanics, morphometrics, and characterdisparity consistently distinguish the two newly erected metriorhynchid subfamilies. This study illustrates together with phylogeny, quantitative assessment of diversity, form, and function help elucidate the pattern of fossil clades.
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Young et al. (2010) studied this question.