Fossils and the tropics, the Eunotiaceae (Bacillariophyta) expanded: A new genus for the Upper Eocene fossil diatom Eunotia reedii and the recent tropical marine diatom Amphora reichardtiana

Abstract

The diatom subclass Eunotiophycidae has recently expanded in composition. While it still includes a single order, the Eunotiales, and two families, the Eunotiaceae and Peroniaceae, the former includes four genera, Eunotia, Actinella, Semiorbis and Desmogonium, while the Peroniaceae includes only one, the genus Peronia. After discovery of the predominantly Southern Hemisphere genus Eunophora, a freshwater taxon superficially resembling species of Amphora, other species of diatoms with similarly confusing morphology have come into sharper focus. The recently described genus Amphorotia, based on Eunotia clevei, may be sister taxon (its most closest relative) to Eunophora. This paper presents evidence for including a Miocene, marine, fossil species, Eunotia reedii, with the more or less tropical species, Amphora reichardtiana, in the same genus. Relationships among the Eunotiaceae are further clarified.