Morphological and molecular evidence for the recognition of Caloglossa fonticola sp. nov. (Delesseriaceae, Rhodophyta) from an underground spring in Guangxi, China

Caloglossa (Ceramiales, Rhodophyta) is a globally distributed euryhaline red macroalgal genus. However, only a few Caloglossa species have been documented in permanent freshwater habitats. Here, a new Caloglossa species, Caloglossa fonticola sp. nov., is described and illustrated from an underground spring in Bama County, Guangxi, China, based on morphological observations and molecular phylogenetic analysis. The new species is morphologically distinguishable from other species in the genus by a unique combination of character states, including thallus internodal blades linear, hardly or slightly constricted at nodes, adventitious branches and endogenous branches both absent, and unicellular rhizoids forming from clusters of wing cells arising from the first three axial cells of the main axis and lateral axis. Phylogenetic analysis based on rbcL and LSU rRNA DNA sequences indicated that Caloglossa fonticola was nested in a well-supported clade with Caloglossa bengalensis (Bootstrap supports for ML/posterior probabilities for BI: rbcL-98/1.00, LSU-100/1.00), with high sequence divergence between these two species (8.2-8.4% for rbcL and 3.2% for LSU), supporting its specific status. This is the first species of the genus Caloglossa reported in spring water habitats. The description of C. fonticola expands the known diversity of Caloglossa.

Automated summary

A new species of the globally distributed red macroalgal genus Caloglossa, Caloglossa fonticola sp. nov., was described and illustrated from an underground spring in Bama County, Guangxi, China. This new species is morphologically distinguishable from other species in the genus and expands the known diversity of Caloglossa.