The camenellan tommotiid Kennardia from the lower Cambrian (Stages 3–4) of South Australia

The camenellan tommotiid Kennardia (Family Kennardiidae) is a relatively rare, poorly known early Cambrian taxon endemic to East Gondwana, characterized by sclerites with an external ornament of strong concentric ribs, but generally lacking or having weakly expressed radial folds, plicae or ribs that occur in other kennardiid taxa. Here we describe distinctive sclerite types of two Kennardia species with mutually exclusive stratigraphic ranges recovered from carbonates in the Hawker Group (Arrowie Basin) and the biohermal Koolywurtie Limestone Member of the Parara Limestone (western Stansbury Basin), South Australia. Isolated sclerite types have distinctive morphology and micro-ornament that enable recognition of the type species Kennardia reticulata, which occurs in strata equivalent to the Kulparina rostrata to Micrina etheridgei biozones (Cambrian Series 2, Stage 3) in the Arrowie Basin of South Australia and the Amadeus Basin in the Northern Territory. Kennardia reticulata is characterized by three more or less coniform sclerite types including a symmetrical A-type sclerite and two asymmetrical B- and C-type sclerites each with two subtypes (B1, B2, C1, C2). All sclerites have a characteristic very fine, nearly equidimensional reticulate micro-ornament. A new species, Kennardia tepperi sp. nov., is restricted to the Dailyatia odyssei Zone (Cambrian Series 2, Stages 3–4) in the Arrowie and Stansbury basins, South Australia. Kennardia tepperi has two subtypes (A1, A2) of the symmetrical A-type sclerite, and two asymmetric types (B and C) sclerites with no subtypes. The new species is distinguished by a micro-ornament consisting of a reticulated ornament superimposed on small sharply pointed pustules on concentric ribs and inter-rib grooves.