The freshwater diatom genus Kobayasiella (Bacillariophyta) in Tasmania, Australia

Abstract

Representatives of the diatom genus Kobayasiella Lange-Bertalot (Bacillariophyta) are common in benthic diatom communities of oligotrophic and dystrophic highland lakes in Tasmania Australia. A taxonomic revision of this genus revealed the presence of four unknown taxa, which are here formally described. Kobayasiella acidophila sp. nov., K. australis sp. nov., K. hodgsonii sp. nov. and K. tasmanica sp. nov. differ from all described Kobayasiella species in dimensions and stria density (K. acidophila, K. hodgsonii), the presence of elongated areolae at the valve apex (K. australis) or the presence of multiple longitudinal ridges on the valve face (K. tasmanica). Kobayasiella hodgsonii was the most widespread and abundant species. It closely resembles Kobayasiella saxicola (Manguin) Lange-Bertalot, which was originally described from New Caledonia. However, specimens belonging to the former species were consistently narrower in comparison with the type specimens of K. saxicola. Given the small size and inconspicuous features of most representatives of the genus Kobayasiella, its global species diversity has almost certainly been underestimated.