Review of the Taxonomy, Diversity, Ecology, and Other Biological Aspects of Order Tanaidacea from Japan and Surrounding Waters

Abstract

The order Tanaidacea is a group of benthic crustaceans, most of which are small, up to a few millimeters long. Tanaidaceans are distributed worldwide, with more than 1200 described species. Following the first taxonomic paper on a Japanese tanaidacean in 1936, many researchers have studied their taxonomy, morphology, reproductive biology, or ecology in the waters around Japan. This chapter presents a brief introduction to tanaidaceans and then reviews what is known of their systematics (taxonomy and phylogeny), biology (including feeding habits, phenology, morphology, reproductive modes, parasites, predators), and ecology in Japan. The chapter ends with a summary and prospects for future research. The general conclusion is that tanaidaceans have been understudied, both globally and within Japan; the 104 nominal species reported from around Japan and the 1200 species reported globally likely represent a fraction of the actual diversity. The phylogeny of tanaidaceans is largely unresolved at all taxonomic levels. Recent, significant new discoveries concerned with herbivory, selfing, skin-digging activity in holothuroid hosts, possible sound production, and tube building suggest that much remains to be learned about their general biology.