Thambetolepis delicata gen. et sp. nov., an enigmatic fossil from the Early Cambrian of South Australia

The acid insoluble sclerites of Thambetolepis delicata gen. et sp. nov. of late Tommotian or immediately post-Tommotian age from near Ardrossan, South Australia, are described. These sclerites, as well as those of Sachites Meshkova 1969 and Halkieria Poulsen 1967, are from multi-sclerite animals similar to Wiwaxia Walcott 1911 together with which they constitute the new class Thambetolepidea. Biological affinities of these fossils are discussed in the light of the complex internal structure of the sclerites. Possible assignments to the opisthobranch gastropods, the polyplacophorans, or the annelids are discussed but the taxonomic position of Thambetolepis and the Thambetolepidea is unresolved.