A new scleritomous metazoan from the Late Ordovician Georgian Bay Formation, southern Ontario

Abstract

A new genus and species of articulated scleritomous metazoan, Curviconophorus andersoni, is described on the basis of a unique specimen from the Late Ordovician Georgian Bay Formation of southern Ontario. The affinities of the organism remain obscure, although the overall morphology of component sclerites suggests a possible relationship with the Agmata, an extinct phylum-level group so far known with certainty only from the Cambrian. Curved, conical elements of the scleritome are preserved as internal moulds and yield no details of ultrastructure or primary composition, precluding detailed comparisons with the aggultinated, internally laminated sclerites of agmatans. Curviconophorus gen.nov. has a scleritome architecture similar to that of the Early Ordovician putative agmatan Dimorphoconus granulatus, though it has fewer elements that are strictly monomorphic.