Reinstatement of <i>Gloiopeltis coliformis</i> Harvey (Gigartinales, Rhodophyta) based on genetic and morphological studies

SUMMARY In the red algal genus Gloiopeltis , six species ( G. complanata , G. compressus , G. dura , G. frutex , G. furcata and G. tenax ) are currently recognized, but genetic analyses using mitochondrial cox 1 and chloroplast psa A, psb A, rbc L and tuf A have suggested occurrence of five unnamed species in Japan. Gloiopeltis coliformis Harvey was described based on the specimen collected in Japan during Rodgers’ North Pacific Exploring Expedition of 1853–1856, but the species was later synonymized with G . furcata . However, genetic examination of the isolectotype specimen of G. coliformis using cox 1, rbc L, and rDNA ITS2 region sequences revealed that the specimen was distinct from G. furcata but is included in one of the five clades of unnamed species examined in the present study. Based on our morphological examinations G. coliformis differed from G. furcata in having somewhat larger thalli often forming adventitious branches. Therefore, we propose reinstatement of the species G. coliformis , and its new Japanese name ‘oshima‐funori’. Gloiopeltis coliformis was shown to be widely distributed in temperate regions from southern Hokkaido to southern Kyushu in Japan and Jeju Island in Korea, whereas G. furcata was distributed in wide range of colder regions in the Northern and Eastern Pacific. The presence of parasporangia was reported in the tetrasporophytes of Gloiopeltis coliformis for the first time in Gigartinales.