New insights into the diversity and distribution of the genus Spirotaenia (Mesotaeniaceae, Streptophyta) in the Neotropics, including the description of S. tetrahelica sp. nov.

Abstract

Spirotaenia is one of the main genera within the family Mesotaeniaceae (Streptophyta), and it is mostly known for its cells with helical chloroplasts. During a taxonomic survey of microalgae in the Bahia State, Brazil, three taxa of Spirotaenia were found, including a new species (S. tetrahelica), which is described herein, and two pioneer records for the Neotropics (S. beijerinckii and S. erythrocephala). This study provides detailed information on these species and other taxa of Spirotaenia reported in the Neotropical region, including a taxonomic key, descriptions, illustrations, comments, and some ecological data. As a result, we now have a better understanding of the diversity and geographic distribution of that genus in the Neotropics, which currently consists of eight species. Brazil has the highest diversity of the genus in that region, with seven species, two of which are likely endemic.