Calliblepharis yasutakei sp. nov. and Hypnea tsudae sp. nov. (Cystocloniaceae, Rhodophyta): novel diversity from the Hawaiian Islands

Surveys of Hawaiian macroalgae over the past 15 years have yielded numerous specimens representing species new to science. Calliblepharis yasutakei sp. nov. is here described based on a plant collected at a depth of 98 m from Kapou, Papahânaumokuâkea Marine National Monument, Hawaiʻi. Phylogenetic analyses of three molecular markers (COI, rbcL, and SSU) and analyses of morphological features were used to describe the new species in the family Cystocloniaceae. Calliblepharis yasutakei sp. nov. grouped with C. fimbriata, C. rammediorum, C. occidentalis and C. jolyi in a clade with full support for the rbcL analysis, representing a distinct lineage within the genus. Phylogenetic and vegetative morphological comparisons demonstrated that the new Hawaiian species is most closely related to C. rammediorum from Israel (rbcL similarity of 96.3%), although no female reproductive structures were found to allow a more comprehensive comparison. In order to determine whether C. yasutakei represents the first confirmed report of the genus Calliblepharis in the Hawaiian Islands, phylogenetic and morphological analysis of the Hawaiian Hypnea saidana (=Calliblepharis saidana) specimen accessioned at the Bernice P. Bishop Museum was performed. These analyses demonstrated that this specimen belongs to a new species in the genus Hypnea, which is here described as H. tsudae sp. nov. C. yasutakei, in addition to being a new species, is also reported as the first confirmed record of the genus Calliblepharis in the Hawaiian archipelago, and the description of H. tsudae brings the number of species for this genus in Hawaiʻi to eight.