Brachauchenius (meaning 'short neck') is an extinct genus of pliosaurid that lived in North America (United States) during the Late Cretaceous. The type species, Brachauchenius lucasi, lived in the Western Inland Sea of North America around 93.5-89.3 million years ago, during the Turonian stage of the Cretaceous. An older specimen from the Barremian of Colombia was considered as part of this genus, representing the first re-occurrence of the non-rhomaleosaurid pliosaurs after a Berriasian-Hauterivian hiatus. However, subsequent analysis of this Colombian specimen shows that it was enough distinctive to warrant a new genus and species, named as Stenorhynchosaurus munozi.