A new marine prasinophyte genus alternates between a flagellate and a dominant benthic stage with microrhizoids for adhesion

Abstract

Prasinophytes (Chlorophyta) are a diverse, paraphyletic group of planktonic microalgae for which benthic species are largely unknown. Here, we report a sand-dwelling, marine prasinophyte with several novel features observed in clonal cultures established from numerous locations around Australia. The new genus and species, which we name Microrhizoidea pickettheapsiorum (Mamiellophyceae), alternates between a benthic palmelloid colony, where cell division occurs, and a planktonic flagellate. Flagellates are short lived, settle and quickly resorb their flagella, the basal bodies then nucleate novel tubular appendages, termed “microrhizoids”, that lack an axoneme and function to anchor benthic c..