Abstract
Our recent morphological studies on the echinoderm collection of the National Museum of Nature and Science, Tokyo (NMST), indicated that the goniasterid starfishes Ceramaster japonicus (Sladen, 1889) and Ceramaster patagonicus (Sladen, 1889) are distributed in the Pacific Oceanside of Japan. In this study, we studied the NMST samples of C. japonicus and C. patagonicus from Japan, by using two mitochondrial DNA genes, the COI and 12S-rRNA, as markers to test relationships between these species in Japan. C. patagonicus sequences from GenBank were mined and included in the analyses. Results of phylogenetic and haplotype network analyses of both genes (final sequence lengths: COI = 317 bp, 12S = 477 bp) suggested that "Ceramaster patagonicus" and "Ceramaster japonicus" from Japanese waters are almost certainly synonymous without any population structure inside Japan.