A New Fossil Salamander (Caudata, Proteidae) from the Upper Cretaceous (Maastrichtian) Hell Creek Formation, Montana, U.S.A

North American Late Cretaceous salamanders are principally known by isolated atlantes and trunk vertebrae. Here I describe a new genus and species of fossil salamander, Paranecturus garbanii, gen. et sp. nov., based on these elements from the lower portions of the Hell Creek Formation (Maastrichtian), Garfield County, northeastern Montana, U.S.A. It is diagnosed by a unique combination of character states that include the presence of an alar-like process of the atlas and a groove on the posterior face of the neural arch and solid dorsal rib-bearers of the trunk vertebrae. My phylogenetic analysis of 13 caudate taxa and 23 atlantal and trunk vertebral characters recovered P. garbanii as a member of the Proteidae. P. garbanii represents the oldest fossil record of the Proteidae and demonstrates that this lineage was present before the Cretaceous-Paleogene mass extinction event.