A late Campanian euselachian assemblage from the Bearpaw Formation of Alberta, Canada: some notable range extensions

Abstract

Herein, we report an euselachian assemblage from the late Campanian Bearpaw Formation recovered from southern Alberta, Canada. This small yet uniquely diverse fauna includes the northernmost occurrences of Paraorthacodus andersoni, Squalus worlandensis, Odontaspis aculeatus, and Archaeotriakis ornatus within the Western Interior Seaway. It also constitutes the first record of P. andersoni, S. worlandensis, and A. ornatus from Canadian deposits. Moreover, we report the stratigraphically youngest record of Cretoxyrhina mantelli. This assemblage is unique in that all the identifiable euselachian species are either pelagic or benthopelagic but not benthic. This is in stark contrast to the batoid-rich euselachian assemblage of the Lethbridge Coal Zone that immediately underlies the Bearpaw Formation in southern Alberta. We attribute this difference to dysoxic bottom waters during the deposition of the formation, rather than to sampling bias.