A new species of <i>Euchonoides</i> (Annelida, Polychaeta, Sabellidae) from Suruga Bay, Japan

Euchonoides is a genus of small sabellid worms composed of two valid species, E. moeone from Hawaii and E. bicincta from Kamchatka and Kurile Islands. We report here a third species from sandy mud sediments in Suruga Bay, Japan. Euchonoides shizuoka sp. nov. is characterized by several unique, distinctive features as follows: a laterally notched collar; a wide glandular ridge on chaetiger 2; enlarged thoracic chaetigers 5–8; distinctive glandular shields on thoracic chaetigers 6–8; an enlarged abdominal chaetiger 1; swollen pad-like structures on the ventral side of abdominal chaetiger 2; a pre-pygidial depression with lateral wings and an anterior bordering margin. A comprehensive description based on the external morphology and supplemented with scanning electron microscopy images, light microscopy, and line drawings, is provided.