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.

DATA AVAILABILITY STATEMENT

The data that support the findings of this study are openly available at Morphobank.org, Project number 4720.

ACKNOWLEDGMENTS

We thank A. Pavlic and C. Kiejko of Edmonton for finding the specimen and donating it to the UALVP collections. Thanks also to P. Currie (University of Alberta) for arranging to have the specimen scanned and Joel Pumple (Permafrost Archives Lab, University of Alberta) for performing the scan. We are also grateful to an anonymous reviewer, reviewer E. J. Hilton, Phylogenetics Editor P. Godoy, and Associate Editor J. Kriwet for providing suggestions to improve the manuscript. The research was supported by Natural Sciences and Engineering Research Council of Canada Discovery Grant 327448 (AMM).

AUTHOR CONTRIBUTIONS

AMM and LEN described the specimen, ran the phylogenetic analyses and prepared the figures. DBB analysed distribution data. AMM prepared the first draft of the manuscript and all authors edited and contributed to the final text.

LIST OF SUPPLEMENTARY FILES

Supplementary File 1: nexus file used in the phylogenetic analysis.

Supplementary File 2: the most parsimonious trees resulting from the phylogenetic analysis.

Supplementary File 3: the 50% majority rule and strict consensus trees from the phylogenetic analysis.