THE OTARIONINE TRILOBITES HARPIDELLA AND MAUROTARION, WITH SPECIES FROM NORTHWESTERN CANADA, THE UNITED-STATES, AND AUSTRALIA

Maurotarion Alberti, 1969, is a diverse otarionine clade that can be r eadily distinguished from Harpidella M'Coy, 1849. Both genera appear i n the Upper Ordovician and range until the Middle Devonian. A new diag nosis for each taxon is given. New species of the genera from the Ordo vician and Silurian of the central Mackenzie Mountains, Northwest Terr itories, Canada, include Harpidella kurrii (Ashgill), H, tikkaneni (Ll andovery), H. greggi (Wenlock), and Maurotarion messieri (Llandovery). Harpidella megalops (M'Coy, 1846), H. triloba (Hu, 1975), H. spinafro ns (Williams in Cooper and Williams, 1935), Maurotarion struszi (Chatt erton, 1971), and M, instita (Whittington and Campbell, 1967) are revi sed.