LAUSR

ABSTRACT Five species are currently recognised in the red algal genus Gloiopeltis (family Endocladiaceae): G. complanata (including the reputedly synonymous Caulacantus compressus), G. dura, G. frutex, G. furcata, and G. tenax. Genetic analyses suggested a considerably greater species diversity within the Japanese region than previously reported. Recently collected specimens of Gloiopeltis from Ryukyu Islands in southern Japan conformed to current concepts of G. complanata in habit and morphology, with relatively small sizes and many short adventitious branches. Our genetic analyses, however, indicated differences at species level. Because gene sequences from material of G. complanata had not yet been analysed, we examined lectotype specimens of Endocladia complanata and Caulacanthus compressus, both housed in the Trinity College Herbarium (TCD), and compared them with sequences from a suite of contemporary Japanese Gloiopeltis specimens. Our sequences of rbcL and cox1 genes as well as rDNA ITS2 region from the lectotype specimen of Caulacanthus compressus were identical to or very similar to the specimens from Ryukyu, but were distinct from authentic Japanese material of Gloiopeltis complanata, the species with which it had been previously synonymised. We therefore concluded that Caulacanthus compressus is a valid species and hereby transfer it to the genus Gloiopeltis as G. compressus comb. nov.