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Adrain, J.M., 1993

Systematics of Silurian trilobites from northern Laurentia

Bibliographic Reference

Adrain, J.M., 1993, Systematics of Silurian trilobites from northern Laurentia: Edmonton, Alberta, Canada, University of Alberta, Ph.D. dissertation, 518 p., illust.


Diverse Silurian trilobite faunas occur in northwestern Canada and the central Canadian arctic. Elements of these faunas are treated herein, together with a small fauna from southwestern Alaska. Five new genera or subgenera are proposed and 21 new species described. Odontopleura and Sinespinaspis n. subgen. are monophyletic odontopleurid sister-groups. Odontopleura (Odontopleura) arctica n. sp. is described from Llandovery (since revised to Ludlow) rocks of Cornwallis Island, central Canadian arctic. A method of unordered parsimony analysis is advocated. The genus Otarion is revised to include a restricted Wenlock-Middle Devonian group of aulacopleurid trilobites. New species from northwestern Canada include O. huddyi and O. beukeboomi. Otarion coppinsensis is a new species from New South Wales, Australia. The genera Otarion, Cyphaspis, Namuropyge, and possibly Dixiphopyge, constitute the Tribe Otarionini. Borealarges is a new trochurine genus with exceptional diversity in the Wenlock and Ludlow of northern Canada. New species from the Cape Phillips Formation of the central Canadian arctic include B. reedi (type species), B. morrisoni, B. tuckerae, and B. s.l. calei. Goodsiraspis packardi n. gen. n. sp. is a derived rorringtoniid that occurs in Ludlow (Ludfordian) rocks of the lower member of the Barlow Inlet Formation at Goodsir Creek, Cornwallis Island. Llandovery representatives of the Subfamily Aulacopleurinae in northwestern Canada include Aulacopleura andersoni n. sp., A.? ranfordi n. sp., and Songkania smithi n. sp. Llandovery trilobites from southwestern Alaska include Paracybantyx occidentalis n. sp., Ligiscus smithi n. sp., Calymene s.l. hoholitnensis n. sp., unnamed species of Scotoharpes, Scharyia, possibly Protocerauroides, and an undetermined warburgelline. New genera of encrinurids from the Douro Formation of the central Canadian arctic include the encrinurine Aegrotocatellus (type species A. jaggeri n. sp.) and the coronocephaline Perirehaedulus (type species Kailia? capra Thomas). Perirehaedulus richardsi n. gen. n. sp. is a second species of the latter. Harpidella and Maurotarion are distinct otarionine clades. New species from northwestern Canada include H. kurrii, H. tikkaneni, K. greggi, and M. messieri.

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