Anatomy and phylogenetic relationships of Temnodontosaurus zetlandicus (Reptilia: Ichthyosauria)

Abstract Parvipelvia is a major clade of ichthyosaurians that diversified during the Triassic-Jurassic transition. The interrelationships early parvipelvians remain unclear and many genera are loosely diagnosed, such as Temnodontosaurus, an ecologically important genus from Early Jurassic Western Europe. One taxon concentrates taxonomic issues: ‘Ichthyosaurus’ acutirostris was previously assigned to Temnodontosaurus for which zetlandicus represents junior synonym. We redescribe holotype (CAMSM J35176) new specimen probably attributable this (MNHNL TU885) Toarcian Luxembourg. find comb. nov. valid species should be referred sharing number traits with nuertingensis trigonodon, despite having distinct cranial architecture. Our phylogenetic analyses under both implied weighting maximum parsimony Bayesian inference recover T. closely related several currently Temnodontosaurus. Species included in form polyphyletic yet well-clustered group among basal neoichthyosaurians, demonstrating monophyly needs thoroughly investigated.