The diatom genera<i>Stellarima</i>and<i>Symbolophora</i>with comments on the genus<i>Actinoptychus</i>

Abstract

Diatom species formerly referred to the genus Symbolophora Ehrenb. are herein assigned partly to Symbolophora sensu Hasle & Sims and partly to Stellarima nom. nov. The generitype for Symbolophora is established as S. trinitatis Ehrenb. and that for Stellarima as S. microtrias (Ehrenb.) comb. nov. Symbolophora has been recorded so far from deposits of middle Eocene to middle Miocene age, whereas Stellarima contains extant as well as extinct species. Symbolophora includes triangular forms hitherto placed in the genera Actinoptychus Ehrenb., Schuettia De-Toni or Cymatogonia Grun.; some circular and hexagonal species currently in the genus Actinoptychus may require transfer to this genus.