A new arthropod from the Early Cambrian of North Greenland, with a 'great appendage'-like antennula

Kiisortoqia soperi gen. et sp. nov. is an arthropod species from the Early Cambrian Sirius Passet Lagerst tte of North Greenland. A head, incorporating four appendiferous segments and biramous limbs, with an anteroposteriorly compressed basipod with a spine bearing median edge, support the euarthropod affinities of K. soperi gen. et sp. nov. Similarities with 'short great appendage' arthropods, or megacheirans, like the nine-segmented endopod, and the flap-or paddle-like exopod, may be symplesiomorphies. The antennula, however, resembles in composition and size the anteroventral raptorial appendage of anomalocaridids. Thus, the morphology of K. soperi gen. et sp. nov. provides additional support for the homologization of the anomalocaridid 'great appendage' with the appendage of the antennular or deutocerebral segment of extant Euarthropoda. (C) 2010 The Linnean Society of London, Zoological Journal of the Linnean Society, 2010, 158, 477-500.