A review of "Leidyosuchus" (Crocodyliformes, Eusuchia) from the Cretaceous through Eocene of North America

A review of all described species referred to Leidyosuchus recognizes six valid taxa: Leidyosuchus canadensis, L. multidentatus, L. sternbergii, L. formidabilis, L. wilsoni, and L. acutidentatus. Leidyosuchus riggsi is a nomen dubium, L. gilmorei is a junior synonym of L. canadensis, and Diplocynodon stuckeri is a junior synonym of L. wilsoni. Phylogenetic analysis of 164 morphological characters indicates a basal position within Alligatoroidea for L. canadensis. The name Listrognathosuchus is established for L. multidentatus, which is an alligtoroid, but difficult to characterize further because of its incompleteness. The remaining taxa form a clade herein named Borealosuchus; this group is related to, but not within, a monophyletic group that includes Alligatoroidea and Crocodyloidea. A close relationship between these taxa and Diplocynodon is rejected. Although presently known only from the Tertiary of Europe, taxa closer to Diplocynodon than to Alligatoridae are expected to occur in the Late Cretaceous.