A literature review of the marine annelids of the Ryukyu Islands: still at the “early-bird” stage

The region of the Ryukyu Islands, in subtropical southern Japan, is a marine biodiversity hotspot, however most marine invertebrate taxa here can be considered grossly understudied. Despite the known high diversity of marine annelids, both in terms of species richness and ecological functions, a review of the knowledge accumulated on them in the Ryukyus is not yet available.

To provide an overview of past research and identify gaps, we reviewed 149 publications related to the topic and compiled 1986 literature records. Despite large discrepancies in groups and environments studied, we found indications of high diversity of marine annelids in the Ryukyus, with 445 nominal species recorded, including 59 described from the region, comprising approximately a quarter of Japan’s marine annelid fauna.