HESIONIDAE (ANNELIDA, POLICHAETA) FROM JAPAN. I. by Hiro ...

28 Kuroshio Biosphere : BULL. BIOL. INST. KUROSHIO Vol. 1, 2004
───── dubia Imajima & Hartman, 1964, p. 83.
───── ── Okuda & Imajima, 1965, p. 502, Figs. 1-5.
? ───── ── Banse & Hobson, 1968, p. 13, Figs. 3i, j.
───── ── Uchida, 1988, p. 78.
MATERIAL EXAMINED.
Kushimoto, Arita, lobster gill net, 7 February, 1979, late K. Ikazaki, collector, 1
specimen; Kada, Wakayama, Wakayama Prefecture, lower tidal zone, 4 June, 1985, 4
specimens; the same locality, 14 September, 1985, 11 specimens; Kuroshima Is. (Ryukyu
Islands, Yaeyama Group), off Nishinohama Beach, 15 m deep, SCUBA diving, 12 Sept.
1986, K. Nomura, collector, 1 specimen; Kushimoto, Fukuro, intertidal zone, 12 April,
1990, 3 specimens; Kushimoto, Ohshima Is., Kashino, 15 m deep, SCUBA diving, 10 May,
1990, Sh. Ui, collector, 1 specimen; Kada, Wakayama, tidal zone, 3 June, 1996, 11
specimens; Kuroshima Is., around the Island, 5-8 m deep, SCUBA diving, 15-17 Dec.
1997, 17 specimens; the same locality, SCUBA diving, 17-20 April, 1998, 91 specimens;
Kushimoto, Arita, intertidal zone, 27 April, 1998, 1 specimen; Tsubaki, Shirahama,
Wakayama Prefecture, 7m, SCUBA diving, 12 April, 1999, 1 specimen; the same locality,
SCUBA diving, 3-11m, 6 Oct. 1999, 2 specimens; the same locality, SCUBA diving, 15m,
30 Mar. 2000, 1 specimen, the same locality, SCUBA diving, 8m, 11 Oct. 2000, 1
specimen, the same locality, SCUBA diving, 12m, 12 Oct. 2000, 1 specimen.
DESCRIPTION.
Body colorless except for pale gray faint markings in sidebody between each
parapodium (Pl. 1, Fig. 1), but the preserved specimens colorless allover. Body 3-9 mm
long with 24-50 setigers in complete specimens, but it seems to be up to ca. 15 mm long
with ca. 70 setigers. Body width 250 µm-1 mm excluding parapodia, and 700 µm-2 mm
including parapodia. The longest fragment 16 mm long with 59 setigers behind the anterior
tentacular segments.
Prostomium sub-rectangular, wider than long, with a depression in posterior margin
(Fig. 1, A). With two antennae, two bi-articulated palpi, and two pairs of eyes. The
antennae inserted in frontal margin of prostomium, rather slender, non-articulated, and
almost as long as the length of prostomium. Palpi situated just ventral to the antennae, and
somewhat shorter than the latter. An articulation occurred about a half of the entire length.
Orangish red eyes situated in the posterior half of prostomium. The anterior pair wide, and
larger than the posterior pair. Without a facial tubercle.
Proboscis without teeth or jaws, but with a circle of 20 papillae. Each papilla
subconical with a ciliated tip. Proboscial margin not ciliated (Fig. 1, F).
Tentacular cirri, dorsal cirri, and anal cirri articulated (Fig. 1, A-E). Each article
long cylindrical in form.
Each of anterior three segments with two pairs of tentacular cirri (Fig. 1, A-B).
Tentacular cirri of segment II situated ventrally than those of segments I and III (Fig. 1,
B). Dorsal tentacular cirri of segment III the longest. Dorsal tentacular cirri of segment I
and ventral tentacular cirri of segment III almost as long as a half of the longest cirri.
Dorsal and ventral tentacular cirri of segment II the shortest, and almost as long as a half of
dorsal tentacular cirri of segment I. Ventral tentacular cirri of segment I somewhat longer