An ankylosaurian dinosaur from the Cenomanian Dunvegan Formation of northeastern British Columbia, Canada

Victoria M Arbour,Derek Larson,Matthew Vavrek,Lisa Buckley,David Evans

doi:10.5194/fr-23-179-2020

Victoria M Arbour, Derek Larson + Show 3 more

Open Access

https://doi.org/10.5194/fr-23-179-2020

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Abstract

Abstract. Fragmentary but associated dinosaur bones collected in 1930 from the Pine River of northeastern British Columbia are identified here as originating from an ankylosaur. The specimen represents only the second occurrence of dinosaur skeletal material from the Cenomanian Dunvegan Formation and the first from Dunvegan outcrops in the province of British Columbia. Nodosaurid ankylosaur footprints are common ichnofossils in the formation, but the skeletal material described here is too fragmentary to confidently assign to either a nodosaurid or ankylosaurid ankylosaur. The Cenomanian is a time of major terrestrial faunal transitions in North America, but many localities of this age are located in the southern United States; the discovery of skeletal fossils from the Pine River demonstrates the potential for the Dunvegan Formation to produce terrestrial vertebrate fossils that may provide important new data on this significant transitional period during the Cretaceous.

Highlights

Terrestrial vertebrate fossils have rarely been reported from the Cenomanian-aged Dunvegan Formation (Burns and Vavrek, 2014; Vavrek et al, 2014), which crops out in northeastern British Columbia and northwestern Alberta
Bony fish and sharks have been recorded from the Dunvegan Formation in Alberta (Hay et al, 2007; Cook et al, 2008; Vavrek et al, 2014), the terrestrial vertebrate body fossil record of the formation has far been limited to a few ankylosaur ossicles from Alberta (Burns and Vavrek, 2014)
The Early and mid-Cretaceous dinosaur skeletal record of western Canada is almost entirely represented by ankylosaurs, including osteoderms from the Berriasian-aged Pocaterra Creek Member of the Cadomin Formation in the Rocky Mountains of southwest Alberta (Nagesan et al, 2020), the exceptionally preserved Borealopelta from the Aptian Clearwater Formation (Brown et al, 2017), and isolated ossicles from the Dunvegan Formation of Alberta (Burns and Vavrek, 2014)

Summary

Introduction

Terrestrial vertebrate fossils have rarely been reported from the Cenomanian-aged Dunvegan Formation (Burns and Vavrek, 2014; Vavrek et al, 2014), which crops out in northeastern British Columbia and northwestern Alberta. The specimen (CMN 59667), a block of sandstone with associated ribs and vertebrae, was collected in 1930 from the Pine River. To our knowledge this is the first dinosaur skeletal fossil discovered in the province, predating by more than 40 years the discovery of Ferrisaurus sustutensis (Arbour and Evans, 2019), first reported by Arbour and Graves (2008). The Dunvegan Formation is the furthest north of the known Cenomanian-aged vertebrate fossilbearing terrestrial units in North America and is of particular interest for testing proposed latitudinal faunal provinciality in the early Late Cretaceous (e.g. Lehman, 2001; Sampson et al, 2010) and understanding its origin

Materials and methods

Geological setting

Systematic palaeontology

Findings

Discussion