Middle Devonian brachiopods from the Bird Fiord Formation, Arctic Canada

Abstract

The late Early Devonian to Middle Devonian Bird Fiord Formation, which is up to 900 m thick, is exposed along an extensive outcrop belt from stretches from Ellesmere Island to Bathurst Island in Arctic Canada. This formation, which encompasses sediments that accumulated in sabkha, deltaic, and shelf settings, is divided into six members. The Blubber Point, Baad Fiord, Norwegian Bay, and Cardigan Strait members, which include sediments that formed on an open marine shelf, are characterized by a diverse biota of brachiopods, mollusks, corals, trilobites, and sponges. The Cross Bay and Grise Fiord members, which encompass sediments that formed in a sabkha and delta plain settings, respectively, are generally devoid of fossils.A collection of 47,026 brachiopods, which came from 140 collections made at 34 locations throughout the outcrop belt of the Bird Fiord Formation, contains 22 species of brachiopods that belong to 21 genera. This biota includes six new species:Gypidula mega, Spinatrypa (Isospinatrypa) parva, Desquamatia (Independatrypa) fortis, Nucleospira stelcki, Warrenella grinnellensis, andCranaena briceae. Four genera (ArcticastrophiaLi and Jones, 2002,BorealistrophiaLi and Jones, 2002,GrinnellathyrisLi and Jones, 2002, andCostacranaenaJohnson and Perry, 1976) and 16 species of brachiopods are endemic to the Arctic Canada. Conversely, the fauna also includes European elements such asNucleospira lens(Schnur),Spinatrypa(Isospinatrypa), andWarrenella. These taxa may indicate that there was some communication between the Canadian Arctic and Europe during Middle Devonian.