Taxonomy and Life History of the Scale Worm Hesperonoe hwanghaiensis (Polychaeta: Polynoidae), newly Recorded in Japan, with Special Reference to Commensalism to a Burrowing Shrimp, Upogebia major

Abstract

A unique scale worm Hesperonoe hwanghaiensis Uschakov and Wu, 1959 (Polychaeta: Polynoidae) was collected from tidal flats in Japan and is described here taxonomically as the second record of this species since its original description from Chinese specimens. Some morphological features of our specimens differed slightly from the original description of this species. Marked differences in growth pattern, morphology of elytra and microhabitat were demonstrated between juveniles (1.8 mm or less in body width) and adults (1.9 mm or more). We estimated the outline of the life history of the scale worm by sampling it in various seasons. The scale worm was commensal with the burrowing shrimp Upogebia major. Juveniles of the scale worm were commonly attached to the ventral or lateral surface of the thorax or abdomen of the host throughout May to September in Isahaya Bay in the Ariake Sea, Kyushu. In July 1998, 89% of the host shrimps were infested by the scale worm. Several juveniles (maximum: 7) of the scale worm often aggregated on a host body, with no adults found on the hosts. The adults were collected from sediment samples. These results suggest that the juveniles mainly live on the surface of the host body and that they later detach themselves from the host body and live freely on the inner surface of the burrow of the host.

Behaviour of the shrimp ectosymbionts, Peregrinamor ohshimai (Mollusca: Bivalvia) and Phyllodurus sp. (Crustacea: Isopoda) through host ecdyses

“…The shrimps of the genus Upogebia construct U-or Y-shaped burrows in muddy sediment and ¢lter suspended matter by creating water currents in the burrows and can deposit feed as well (Dworschak, 1987;Gri¤s & Suchanek, 1991;Nickell & Atkinson, 1995;Coelho et al, 2000;Kinoshita, in press). Upogebiid shrimps serve as hosts for many ectosymbiotic animals and burrow co-habitants (MacGinitie, 1930;MacGinitie, 1935;Shoª ji, 1938;Grossman, 1979;R|¨os & Carvacho, 1983;Markham, 1986;Hayashi, 1998;Sato et al, 2001;Itani, in press).…”

Heteromysis (Heteromysis) microps (Crustacea, Mysidae), a commensal species for Upogebia pusilla (Crustacea, Upogebiidae) in Arcachon Bay (NE Atlantic Ocean)

“…Indeed, through its intense bioturbation activity, it greatly influences sedimentary biogeochemical processes and enhances fluxes across the sediment-water interface with knock-on effects on the whole benthic communities (Ziebis et al, 1996;D' Andrea and DeWitt, 2009;Pascal et al, 2016). Upogebia also intensively ventilate their burrows through pleopod beating (Dworschak, 1981) for respiratory and trophic requirements (Sato et al, 2001). Deep and well irrigated mud-shrimp burrows represent efficient refuges against predation for a variety of commensal species such as shrimps (e.g.…”

“…Peregrinamor ohshimai Shôji, 1938) (Kato and Itani, 1995), polychaetes (e.g. Hesperonoe hwanghaiensis Uschakov & Wu, 1959) (Sato et al, 2001), phoronids (e.g. Phoronis pallida Silén, 1952) (Santaga, 2004) and goby fishes (e.g.…”

Life history of the copepod Hemicyclops gomsoensis (Poecilostomatoida, Clausidiidae) associated with decapod burrows in the Tama-River estuary, central Japan

“…In addition, it has progressively become clearer that these burrows provide diverse organisms with living habitats, and that such associations underpin the presence of highly diverse assemblages in areas of considerable environmental fluctuation, such as intertidal zones and estuaries (e.g. MacGinitie 1935, MacGinitie & MacGinitie 1949, Dobbs & Guckert 1988, Sato et al 2001, Itani 2004, Anker et al 2005, Koller et al 2006.…”