Spiophanes wigleyi Pettibone, 1962

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 : 128-130

Spiophanes wigleyi Pettibone, 1962

Figs. 1E, 2A,G, 8–10

Spiophanes wigleyi Pettibone, 1962: 83 , figs. 5,6.–* Hartman, 1965: 153, pl. 28, figs. e,f.–* Foster, 1971: 43–46, 76–85.–Blake & Kudenov, 1978: 224, fig. 26.–* Johnson, 1984: 6–11, fig. 6(4).

Spiophanes urceolata Imajima, 1991: 132–136 , figs. 10–12 new synonymy.

Type material. PARATYPES: North Atlantic Ocean, 40°0.9'N 68°58'W, Georges Bank Area , off Massachusetts , in 70–135 m, 22 Aug 1957, 2 specimens ( USNM 30402 ) .

Non-type material. NORTH ATLANTIC OCEAN: Norwegian Sea, 60°47.74'N 3°26.85'E, in 333 m, 14 May 1998, 1 specimen (ZSRO P716); 60°45.04'N 3°26.85'E, in 330 m, 13 May 1998, 1 specimen (ZSRO P717). SOUTH ATLANTIC OCEAN/INDIAN OCEAN: South Africa, off Cape Town, 34°16'S 18°38'E, in 59 m, 1967, 9 specimens (South African Museum A20781 ); mixture of 9 stations off South Africa J.H. Day, 29 Nov 1960, 1 specimen (BMNH 1961.19.596/634). SOUTH PACIFIC OCEAN: Milne-Edwards Deep: 8°21'S 81°25'W, in 1296–1317 m, 14 Oct 1965, several specimens (LACM-AHF ABII-94); 7°59'S 80°37'W, in 991–1015 m, 14 Oct 1965, 4 specimens (LACM-AHF ABII-90). AUSTRALIA: NEW SOUTH WALES: E of Providential Head, Wattamolla, 34°0.8'S 151°08.5'E, in 50 m, 1 Feb 1990, 1 specimen (AM W22948). VICTORIA: S of Lakes Entrance [37°53'S 148°00'E], May 1969, 2 specimens (AM W13018); Tasman Sea: eastern slope, 38°06.2'S 149°45.5'E, in 188 m, 14 Oct 1984, 8 specimens (MV F90017 ), 38°10.3'S 149°57.2'E, in 592 m, 14 Oct 1984, 3 specimens (MV F90010 ); Bass Strait: 38°08'S 148°35'E, May 1969, 1 specimen (AM W13016), 38°59'S 148°34'E, in 466 m, May 1969, 3 specimen (AM W13017); Western Bass Strait: 39°0.5'S 142°33'E, in 207 m, 9 Oct 1980, 1 specimen (MV F90025 ), 39°0.6'S 142°29'E, in 630 m, 9 Oct 1980, 1 specimen (MV F90026 ). TASMANIA: Eastern Bass Strait: 38°57.8'S 148°26.5'E, in 130 m, 15 Nov 1981, 5 specimens (MV F90023 ), 39°00'S 148°25'E, in 92 m, 14 Oct 1984, 1 specimen (South Australian Museum E3199); 39°02.4'S 148°30.6'E, in 120 m, 15 Nov 1981, 32 specimens (MV F90078 ), 39°31.2'S 148°24.4'E, in 40 m, 15 Nov 1981, 1 specimen (MV F90020 ), 39°44.8'S 146°40.6'E, in 124 m, 14 Nov 1981, 3 specimens (MV F90018 ); Central Bass Strait, 39°43.5'S 146°18.8'E, in 80 m, 13 Nov 1981, 2 specimens (MV F90075 ); Western Bass Strait: 40°06'S 143°16'E, in 187 m, 11 Oct 1980, 1 specimen (MV F90022 ), 40°06'S 143°17'E, in 158 m, 11 Oct 1980, 2 specimens (MV F90024 ); Tasman Sea: 55 km E of Babel Island, 40°00.0'S 148°58.0'E, in 1130 m, 11 Oct 1984, 10 specimens (MV F90015 ), 20 km E of Falmouth, 41°32.9'S 148°35'E, in 122 m, 10 Oct 1984, 11 specimens (MV F90003 ), 30 km NNW of Cape Sorell, 42°10.9'S 144°48.9'E, in 160 m, 20 Oct 1984, 1 specimen (MV F90007 ), Maria Island, 42°37'S 148°20'E, in 102 m, 9 Oct 1984, 7 specimens (MV F90009 ).

Additional material. Spiophanes urceolata , North Pacific Ocean: Japan, 35°10.5'N 139°34.3'E–35°11'N 139°34.4'E, in 92 m, Sep 1979, holotype (NSMT H335).

Description. Specimens up to 1.5 mm wide. Incomplete paratype from Massachusetts with 38 chaetigers, 0.8 mm wide, 9.0 mm long. Incomplete large Australian specimen with 28 chaetigers, 1.1 mm wide, 7.5 mm long. Body slender, subcylindrical. Prostomium broad anteriorly, bellshaped to subtriangular or almost oval-shaped, with or without blunt, very short anterolateral projections; tapered posteriorly to elevated, sometimes pigmented tip (Fig. 8A,C). Occipital antenna absent. Usually 2 pairs of eyes, anterior pair slightly further apart. Nuchal organs as pair of dorsal loops, extending from posterior prostomium margin to beginning of chaetiger 4 (Figs. 2A, 8A). Peristomium well developed. Parapodia of chaetiger 1 in dorsolateral position; postchaetal lamellae cirriform, equal in length (Figs. 2A, 8A,D). Parapodia of chaetigers 2 and 3 also dorsolateral, parapodium of chaetiger 4 lateral. Postchaetal notopodial lamellae of parapodia of chaetigers 2–4 cirriform to subulate, longest at notopodium in chaetiger 3; neuropodial postchaetal lamellae subulate (Fig. 8B,E,F). Chaetigers 5–8 with subtriangular notopodial lamellae, gradually increasing in size, reaching significant size in chaetiger 8; neuropodial postchaetal lamellae reduced (Fig. 8G). From chaetiger 9, notopodial lamellae subulate, with slender tips; neuropodial lamellae reduced (Fig. 8H,I). Parapodial glands of chaetigers 5–8 with indistinct, crescent-shaped, horizontal glandular openings (Fig. 1E); glandular organs of chaetigers 9–14 open as lateral vertical slits. Ventrolateral intersegmental genital pouches absent. Dorsal ciliated crests from chaetigers 15 or 16. Chaetiger 1 usually with 1 stout, crook-like chaeta in neuropodia; other chaetae all capillaries (Fig. 9A,C,K); notochaetae arranged in tuft; neurochaetae in 2 rows. Notopodia of chaetigers 2– 4 with capillaries with narrow sheaths (Fig. 9B), arranged in tuft; neurochaetal capillaries with narrow and broad sheaths (Fig. 9G,H), arranged in 2 rows. Notopodial capillaries of first 4 chaetigers only slightly longer than those of subsequent chaetigers. Chaetigers 5–14 with stout, bilimbate neurochaetae, distally pointed (Fig. 9F,J), in 1–2 indistinct rows; notochaetae with narrow sheath, in 3 rows. From chaetiger 15, notopodial capillaries with narrow sheath, arranged in tuft; neuropodia with quadridentate hooded hooks (Figs. 2G, 9I), initially with 10 or 11 hooks in single row in Australian specimens, up to 14–16 hooks in specimens from Japan; hooks usually in smaller numbers in more posterior chaetigers. Bacillary chaetae thin, hirsute, with brush-like tips, can be present on chaetigers 5–8. One or sometimes 2 thin capillaries in the position of ventral sabre chaetae from chaetiger 4 (Figs. 9D, 10A,B). Stout ventral sabre chaeta and usually additional thin capillary present from chaetiger 15 accompanying the hooks (Fig. 10C), sabre chaeta appearing granulated near tip (Fig. 9E). Single stout, bent chaetae with broad sheath in far posterior notopodia. Pygidium with 4–6 anal cirri.

Pigmentation. Notopodial postchaetal lamellae of chaetigers 9–15 with reddish-brown pigment in proximal region, darkest on chaetigers 12–15 (Fig. 8A).

Methyl green staining pattern. No distinct methyl green staining pattern: areas most intensively stained are pigmented notopodial lamella of chaetigers 9–15; also posterior tip of the prostomium appears to be darker than surrounding area after staining.

Biology. Species recorded from depths of 40–1130 m in all sediments. Gravid specimen found in May (Australia, Victoria: Bass Strait, AM W13016).

Remarks. Spiophanes wigleyi is the most readily recognized species in the genus and is characterized by the rounded shape of the prostomium together with the presence of large numbers of hooded hooks and a nuchal organ forming a pair of dorsal loops extending to chaetiger 4. The pigmentation of notopodial lamellae of chaetigers 9– 15 and size and shape of the postchaetal lamellae in chaetiger 8 notopodia are also characteristic. The development of glandular openings in chaetigers 5–8 is unique among currently described Spiophanes species ; unfortunately, these openings are difficult to observe under the light microscope. Imajima (1991) described the species S. urceolata as differing from S. wigleyi in (a) the shape of the prostomium being triangular to bell-shaped, with a rounded or truncate anterior margin, rather than somewhat ovum-shaped with a rounded anterior margin, (b) the arrangement of notopodial capillary chaetae in three rows throughout rather than two rows, and (c) ventral sabre chaetae being present from chaetiger 4 rather than 9. Examination of specimens from Australia, South Africa, and the holotype of S. urceolata from Japan, and two S. wigleyi paratypes from Massachusetts revealed that the arrangement of notopodial capillary chaetae in 3 distinct rows can only be observed on chaetigers 5–14 on all specimens and, furthermore, it seems to be a character which can be attributed to all species in the genus. The above mentioned differences in the shape of the prostomium match well with the variability of this character in S. wigleyi . However, the most confusing character listed by Imajima (1991) was the first appearance of sabre chaetae in the neuropodia of chaetiger 4. Blake (1996) reported for Californian specimens of S. wigleyi sabre chaetae to be first present from chaetigers 15–16, accompanying the hooks.

Pettibone (1962) observed them first in chaetiger 9 in material from the North Atlantic. Usually the stout sabre chaetae are easy to observe in dissected parapodia or even on entire specimens. In the case of S. wigleyi , the situation is more complicated. The stout bilimbate neurochaetae on chaetigers 4–14 closely resemble sabre chaetae and thus make it difficult to detect unambiguously the first appearance of sabre chaetae. Examination of material included in this study confirmed the presence of 1–2 chaetae in the inferiormost position slightly apart from remaining neurochaetae, regarded to be the position of a sabre chaetae, from chaetiger 4 (Fig. 10A,B). These chaetae vary in thickness, but usually are thinner than other chaetae in the respective neuropodia. This observation is also partly reflected in the drawings by Imajima (1991) and Pettibone (1962). Since these thin chaetae are present in hook-bearing neuropodia, now accompanying the normal sabre chaetae (Fig. 10C), we regard them as chaetae different from sabre chaetae and consider sabre chaetae in S. wigleyi to first appear from chaetiger 15.

Geographical distribution. Cosmopolitan. North and South Pacific Ocean: Australia, Japan, California; North and South Atlantic Ocean: off Massachusetts, off Ireland and Norway, off South Africa; Indian Ocean.