Ptilothamnion richardsii (Rhodophyta) is a chantransia stage of Batrachospermum

Abstract

Four specimens attributable to the freshwater red algal taxon, Ptilothamnion richardsii, were examined from locations in Australia and French Guiana, and partial rbcL gene sequence data were obtained. Phylogenetic analyses showed these specimens to be allied to taxa in the Batrachospermales. The two specimens from Australia were determined to be Batrachospermum antipodites, differing from that taxon by only 15 bp (1.2%). The two specimens from French Guiana were within the Batrachospermum section Contorta clade, but differed considerably (≥8%) from the taxa for which there are presently rbcL gene data. The sequence data clearly show these specimens to be chantransia stages of Batrachospermum..