The epizoic marine diatom Sceptronema orientale (Licmophoraceae, Licmophorales): epitypification and emendation of specific and generic descriptions

Abstract

Sceptronema orientale was found epizoic on the harpacticoid copepod Euterpina acutifrons (Dana) collected from several locations along Bahía Anegada, Province of Buenos Aires, Argentina. Material was examined with light and scanning electron microscopy and new data about the morphology of the chloroplast and ultrastructural details of the girdle, valves, apical slit fields and rimoportulae pattern were obtained. Based on this new knowledge the descriptions of the species and of the monotypic genus Sceptronema are emended. Considering that in the protologue three pictures were designated as iconotype, the material from Ría del Jabalí is chosen as an epitype to serve as the interpretative type of Sceptronema orientale. A comparison with the morphologically similar genera Licmophora and Gato was conducted and the inclusion of Sceptronema in the Family Licmophoraceae, Order Licmophorales is proposed.