Morphological and molecular reassessment of three species ofBesa(Phyllophoraceae, Rhodophyta) from the North-west Pacific

We investigated species referred to as 'Ahnfeltiopsis flabelliformis' from the Far Eastern seas of Russia as well asBesa catenata(Yendo) M.S.Calderon & S.M.Boo from Mie Prefecture (Shima Peninsula, Japan, near to its type locality) morphologically and by analysis of sequences of plastidrbcL and mitochondrial COI-5P genes. Morphological and phylogenetic analyses showed thatAhnfeltiopsis flabelliformisdoes not occur in the Far Eastern seas. All algae previously identified as 'A. flabelliformis' from Russian waters belong to two morphologically and genetically distinct species that should be referred to the genusBesaasB. divaricata(Holmes) M.S.Calderon & S.M.Boo andB. japonica(Suringar) A.V. Skriptsova & S.Y.Shibneva, comb. nov. We found an unattached form ofB. divaricataand named it asB. divaricataf.ahnfeltioidesA.V.Skriptsova & S.Y.Shibneva based on its morphological and ecological features.

Automated summary

The study revealed that 'Ahnfeltiopsis flabelliformis' does not occur in the Far Eastern seas, and algae previously identified as such in Russian waters belong to two distinct species within the genus Besa. Additionally, a new unattached form of B. divaricata was discovered based on morphology and ecological features.