Sheathia shaoguanensis sp. nov. (Batrachospermales, Rhodophyta), a new freshwater red algal species from South China

The freshwater red algal order Batrachospermales has a triphasic life history, of which the morphological characteristics of “ Chantransia ” stages are very similar to those of the genus Audouinella. In this study, two gametophyte stage specimens (CQM 21 and CQW 23) and four “ Chantransia ” stage specimens (CQ 003, CQM 22, CQW 24, and GD 247) were collected from Chongqing Municipality and Guangdong Province in China. Based on morphological data, all four “ Chantransia ” isolates were similar to A. pygmaea, whereas the morphological characteristics of CQM 21 and CQW 23 were in good agreement with the circumscription description of Sheathia dispersa.

The rbc L and COI- 5 P analyses suggested that all six specimens belong to the genus Sheathia and supported the proposal of a new species, S. shaoguanensis sp. nov. Nevertheless, the five specimens from Chongqing (including the two gametophyte stage and three “ Chantransia ” stage specimens) were all assigned to S. dispersa. This represents the first report of the genus Sheathia in the Yangtze River.