Article: Monograptids from the Upper Silurian and Lower Devonian of Yukon Territory, Canada
Dennis E. Jackson and Alfred C. Lenz
Monograptids recorded and described from Arctic Canada for the first time comprise Monograptus cf. cornutus (Urbanek), M. cf. balticus Teller and M. helicoides sp. nov. from probable late Ludlovian; M. bouceki Pribyl and Saetograptus pilosus sp. nov. from mid-Pridolian; M. uniformis angustidens Pribyl and M. uniformis parangustidens subsp. nov. from the latest Pridolian angustidens Zone; M. aequabilis aequabilis (Pribyl) and M. cf. hercynicus subhercynicus Willefert from the lower Lochkovian uniformis Zone; and M. aequabilis notoaequdbttis Jaeger and M. cf. craigensis Jaeger from the Pragian. In addition, the existence in Yukon Territory of M. uniformis uniformis Pribyl is confirmed. The number of species and subspecies known from the Pridolian and Lower Devonian strata in Yukon Territory is herein increased to eleven and nine respectively. The question of the youngest known species of Monograptus is also discussed.