A new sturgeon from the Upper Cretaceous Horseshoe Canyon Formation in central Alberta, Canada

Abstract

The posterior portion of a sturgeon skull preserved in a nodule was recovered from the latest Campanian sediments of the Horseshoe Canyon Formation in the city of Edmonton, Alberta, Canada. It is described here as a new genus and species of Acipenseriformes. The skull represents an individual of at least 2 meters in total length. This species is of particular interest because different bones of the skull show a surface ornamentation with different patterns; the clavicle has large pits, the dermal skull bones have smaller pits and radiating ridges, and the subopercle shows fine radiating ridges. The new taxon, here named †Boreiosturion labyrinthicus, can be confidently included in the extant family Acipenseridae but a phylogenetic analysis does not further resolve relationships. This fossil is the first documentation of sturgeon in the latest Campanian of North America, and bridges the gap between the mid-Campanian assemblage of Dinosaur Park and the late Maastrichtian material from the Hell Creek Formation.