Spiophanes modestus, MEISSNER & Hutchings, 2003

MEISSNER, Karin & Hutchings, Pat A., 2003, Spiophanes Species (Polychaeta: Spionidae) From Eastern Australia-With Descriptions of New Species, New Records and an Emended Generic Diagnosis, Records of the Australian Museum 55, pp. 117-140 : 120-123

Spiophanes modestus n.sp.

Figs. 2D, 3

Spiophanes cf. kroeyeri .–Blake & Kudenov, 1978: 225, fig. 27, in part.

Spiophanes bombyx .–Blake & Kudenov, 1978: 224, in part.– Hutchings & Murray, 1984: 62, in part.

Spiophanes sp. 1 .–Wilson & McDiarmid, 2003.

Type material. HOLOTYPE: Australia, New South Wales , Hawkesbury River , Juno Head – Hungry Beach , 33°34.5'S 151°16.5'E, in 10 m, 5 May 1977 ( AM W 28192 ). PARATYPES: Australia, New South Wales , Hawkesbury River : Juno Head–Hungry Beach , 33°34.5'S 151°16.5'E, in 10 m, 5 May 1977, 5 specimens ( AM W196361 , AM W 196355 , AM W 196359 ), in 4 m, 1 specimen ( AM W196350 ) and 3 Aug 1977, 4 specimens ( AM W196352 , AM W 196358 , AM W 196360 ) .

Non-type material. Australia, QUEENSLAND: Halifax Bay, N of Townsville, 19°10'S 146°37'E, in 2–5 m, Jan 1977,>80 specimens (AM W202313, AM W202314, AM W202316, AM W202317); Pallarenda Beach, N of Townsville, 19°12'S 146°46'E, 27 Aug 1977, 1 specimen (AM W18103); Gladstone, Calliope River, in 8 m, Jan 1983, 1 specimen (AM W198054); Moreton Bay, Middle Banks, 27°12'S 153°32'E, Nov 1975, 2 specimens (QM G11594), Nov 1983–Nov 1984,>50 specimens (QM G218423). NEW SOUTH WALES: Burwood Beach, 32°57.52'S 151°44.72'E, Apr 1975, 1 specimen (AM W8947); Pittwater: 33°35.9'S 151°18.26'E, in 15 m, 6 May 1994 and 9 Oct 1995, 3 specimens (AM W23699,AM W23702); E of Malabar: 33°57.49'S 151°16.14'E, in 30 m, 17 Apr 1989, 1 specimen (AM W20704); Botany Bay: Yarra Bay, 33°58.9'S 151°12.1'E, 12 Feb 75, 5 specimens (AM W18978, AM W19017, AM W195473), W of Frenchmans Bay, 33°59.3'S 151°13.1'E, 16 Jan 1975, 8 specimens (AM W195508), NE of Dolls Point, 33°59.5'S 151°09.6'E, 17 Jan 1975, 1 specimen (AM W19030), W of La Perouse, 33°59.5'S 151°13'E, in 12 m, 21 Jan 1976, 1 specimen (AM W14632), N of Kurnell, 33°59.52'S 151°12.55'E, in 13 m, 10 Mar 1977, 19 specimens (AM W14638–W14640), W of La Perouse, 33°59.52'S 151°12.55'E–34°S 151°13.5'E, in 15–19 m, Jan–Feb 1977, 9 specimens (AM W14633– W14637), W of Bare Island, 33°59.6'S 151°12.2'E, 2 Feb 1975, 1 specimen (AM W195438).

Other species examined. Spiophanes bombyx : NORTH ATLANTIC OCEAN: North Sea, German Bight, 54°20.01'N 7°20.01'E, in 43 m, 26 May 1987, several specimens (SM 4950); 55°54'N 3°27.6'E, in 65 m, 10 Aug 1990, 2 specimens (SM 6476); 55°46.93'N 3°52.38'E–55°53.09'N 3°28.8'E, in 48.4 m, 10 Aug 1990, 3 specimens (SM 6480); 53°41.46'N 6°59.58'E, in 3.5 m, 13 Mar 1989, 8 specimens (SM 6527). MEDITERRANEAN: Spain, between Cape San Antonio and Valencia harbour, 29 Apr 1996, two specimens (MNCN 16.01/2648, 2661). INDIAN OCEAN: 34°16.8'S 18°42.8'E, in 60 m, 25 Feb 1959, several specimens (South African Museum A20779 ). PACIFIC OCEAN: Alaska, Bering Sea, 58°46.36'N 164°14'W, in 35 m, 23 May 1976, 2 specimen (CAS 23887); Alaska, Chukchi Sea, 67°44.29'N 164°33.45'W, in 5.7 m, 17 Aug 1976, 1 specimen (CAS 1675); California, 37°49.27'N 122°25.55'W, in 58–67 m, 24 Sep 1973, several specimen (CAS 1915); 37°46'N 122°41.5'W, in 31 m, 14 Aug 1973, several specimen (CAS 123655).

Description. Holotype complete specimen (posterior region regenerated) with 50 chaetigers, 12 mm total length, about 0.9 mm wide. Other specimens between 0.5–0.9 mm wide. Body slender, subcylindrical. Prostomium broad anteriorly, bellshaped, with distinct anterolateral horns (Fig. 3A). Occipital antenna short. Two pairs of eyes sometimes present, anterior pair further apart and crescent-shaped, posterior pair as small black spots. Nuchal organs as two straight, parallel bands along dorsum, becoming divergent, undulate bands between chaetigers 15–17 (Fig. 3C). Peristomium moderately developed as lateral bulges. Parapodium of chaetiger 1 oriented dorsally; postchaetal lamellae cirriform, equal in length. Postchaetal lamellae of parapodia 2–4 cirriform, but those of neuropodia becoming gradually broader at base (Fig. 3B,D). Chaetigers 5–8 each with rounded notopodial and reduced neuropodial postchaetal lamella (Fig. 3F). From chaetiger 9, notopodial lamella with small triangular base and tapered slender tip; neuropodial lamella reduced (Fig. 3E). Chaetal spreader “2+3 type” with undulate glandular opening well developed in chaetigers 5–7; glandular opening absent in chaetiger 8; glandular organ of chaetigers 9–13 opens as lateral vertical slit (Fig. 2D). Ventrolateral intersegmental genital pouches absent. Dorsal ciliated crests apparent from chaetiger 15 (Fig. 3C). Chaetiger 1 with 1–2 stout, crook-like chaetae in neuropodium, remainder of chaetae simple capillaries; notochaetae very long, reaching back to chaetiger 4 or 5, arranged in a tuft; neurochaetae arranged in 2 rows. Chaetigers 2–4 with simple and unilimbate capillaries (Fig. 3G), the latter becoming more numerous and sheaths becoming more distinctive from chaetigers 2–4; notochaetae in tufts, neurochaetae arranged in 2 rows. Chaetigers 5–13 with stout, bilimbate neurochaetae, distally pointed (Fig. 3J,H), arranged in 1–2 rows; notochaetae each with broad distal sheath, arranged in 3 rows. From chaetiger 14, notopodial capillaries with narrower sheath, arranged in tuft; neuropodial hooks quadridentate without hoods (Fig. 3K), initially 6–8 hooks arranged in 1 row, smaller numbers in more posterior chaetigers. Bacillary chaetae are thin, hirsute bristles with brush-like tips, may be exposed on chaetigers 5–7. Ventral sabre chaetae from chaetiger 4, appearing granulated near tip when viewed with light microscopy, each with cryptic ridge (Fig. 3I). Few stout, curved notochaetae in far posterior parapodia. Pygidium with 2 dorsolateral anal cirri.

Pigmentation. Conspicuous pigmentation absent.

Methyl green staining pattern. Intensely stained glandular patches visible in dorsal region of chaetigers 9–14, if specimens in good condition (Fig. 3A,C).

Biology. Species inhabits shallow water areas down to 30 m depth. All sediment types. Gravid specimens observed from January to March (AM W14635; W14638).

Remarks. The species is characterized by the presence of hooks without hoods from chaetiger 14. It clearly differs from S. bombyx Claparède in the presence of a short occipital antenna instead of lacking one, and having non-hooded hooks rather than hooks with hoods being present.

Etymology. modestus —Latin for modest; referring to the sparse development of parapodial postchaetal lobes in anterior chaetigers, the small antenna and generally fairly small size.

Geographical distribution. Australia: Queensland, New South Wales.