Current taxonomic studies on dicyemid fauna in the Kumano Sea

Abstract

Dicyemids (phylum Dicyemida) are endosymbionts that typically are found in the renal sac of benthic cephalopod molluscs. The dicyemid bodies consist of only 8 to 40 cells, which are the fewest in number of cells in metazoans, and are organized very simply. Typically, two or three dicyemid species are found in a single specimen of the host, and most of them show high host specificity. Dicyemid species have been examined in the benthic cephalopods collected from the Kumano Sea at a seafloor depth of 150–400 m using bottom trawl nets since 2013. Twenty-five undescribed species of dicyemids, included in five genera, were found in 15 species of cephalopods. There is a considerable diversity of dicyemids in relatively narrow range of localities of the Kumano Sea. Here current taxonomic studies on dicyemid fauna in the Kumano Sea are briefly reported.