Data from: Peculiar macrophagous adaptations in a new Cretaceous pliosaurid

During the Middle and Late Jurassic, pliosaurid plesiosaurs evolved gigantic body size and a series of craniodental adaptations that have been linked to the occupation of an apex predator niche. Cretaceous pliosaurids (i.e. Brachaucheninae) depart from this morphology, being slightly smaller and lacking the macrophagous adaptations seen in earlier forms. However, the fossil record of Early Cretaceous pliosaurids is poor, concealing the evolution and ecological diversity of the group. Here, we report a new pliosaurid from the Late Hauterivian (Early Cretaceous) of Russia. Phylogenetic analyses using reduced consensus methods recover it as the basalmost brachauchenine. This pliosaurid is smaller than other derived pliosaurids, has tooth alveoli clustered in pairs and possesses trihedral teeth with complex serrated carinae. Maximum-likelihood ancestral state reconstruction suggests early brachauchenines retained trihedral teeth from their ancestors, but modified this feature in a unique way, convergent with macrophagous archosaurs or sphenacodontoids. Our findings indicate that Early Cretaceous marine reptile teeth with serrated carinae cannot be unequivocally assigned to metriorhynchoid crocodylomorphs. Furthermore, they extend the known diversity of dental adaptations seen in Sauropterygia, the longest lived clade of marine tetrapods.Nexus_fullNexus full dataset with treesPlios_full_BL.nexNexus reducedNexus reduced dataset with treesPlios_red_BL.nexSupplementary materialAssociated bivalve remains, recoding of Anguanax zignoi, stratigraphic age data for OTUs, additional phylogeny and ancestral state reconstruction figures.SuppInfo.docxSupplementary InformationAssociated bivalve, measurements, taxon-age data, R code, supplementary phylogeny figures.SuppInfo.doc