Revision of the type material of Diploneis zannii Frenguelli (Bacillariophyceae)

Abstract

Diploneis zannii was first described from the Esteros del Iberá, a subtropical wetland from Argentina. Type material of the species was studied with light and electron microscopy and compared to some similar taxa: D. fusca, D. insolitus, D. lenzii, D. smithii and D. finnica and other material collected from Brazil and Uruguay. We confirm the validity of Diploneis zannii as a species and present an emended diagnosis derived from new information on its morphology. A lectotype and isolectotype are designated.