Spiophanes viriosus, 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 : 123-125

Spiophanes viriosus n.sp.

Figs. 1A, 2E,H, 4, 5

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

Spiophanes sp. 2 .–Wilson & McDiarmid, 2003.

Type material. HOLOTYPE: Australia, Queensland , Moreton Bay , Peel Island , 27°3'S 153°21'E, in 7.93 m, Mar 1970, ( QM G 10387 ). PARATYPES: Australia, Queensland : Moreton Bay : Middle Banks , 27°12'S 153°32'E, Nov 1983–Nov 1984,> 50 specimens ( QM G 218424 ), 27°15'S 153°15'E, Sep 1976, 6 specimens ( MV F42850 ) and Sep 1976, 3 specimens ( MV F42849 ), Bramble Bay , 27°18'S 153°06'E, Sep 1972, 2 specimens ( QM G 10631 ), Peel Island , 27°3'S 153°21'E, in 4.7 m, Jun 1970, 1 specimen ( QM G10415 ), in 3.35 m, Jun 1970, 1 specimen ( QM G10399 ), in 9.5 m, Jun 1970, 1 specimen ( QM G10353 ).

Description. Holotype incomplete, with 63 chaetigers; total length 28 mm, width 1.5 mm. Paratypes between 0.8–1.7 mm wide. Body slender, subcylindrical. Prostomium broad anteriorly, bell-shaped to subtriangular, with distinct anterolateral projections (Fig. 4A). Occipital antenna long, slender. Up to 2 pairs of eyes. Nuchal organs as two straight, parallel lines along dorsum; when fully developed, lines slightly diverging posteriorly terminating between chaetigers 17–18 (Fig. 4G). Peristomium well developed. Parapodia of chaetiger 1 orientated dorsolaterally; postchaetal lamella cirriform, neuropodial one more robust (Fig. 4A). Postchaetal notopodial lamellae of parapodia 2–4 long, cirriform; lamellae of neuropodia shorter, subulate, tapering to slender tip (Fig. 4A,C). Chaetigers 5–8 with short, rounded notopodial and reduced neuropodial postchaetal lamellae (Fig. 4E). From chaetiger 9, each notopodial lamella with small triangular base and long slender tip; neuropodial lamellae reduced (Fig. 4D,F). Chaetal spreader “2+3 type” with undulate glandular opening in chaetigers 5–7 (Figs. 1A, 4B); glandular opening in chaetiger 8 absent; glandular organ of chaetigers 9–14 opens as lateral, vertical slit. Fully developed ventrolateral intersegmental genital pouches present between chaetigers 14–15 (Figs. 2H, 5A). Dorsal ciliated crests apparent from chaetiger 18 (Fig. 5A). Chaetiger 1 usually with 1 stout, crook-like chaeta in each neuropodium; remainder of chaetae capillaries; notochaetae arranged in a tuft; neurochaetae in 2 rows. Notopodia 2–4 with simple capillaries and capillaries with narrow sheaths, arranged in a tuft (Fig. 5F); neurochaetae capillaries with narrow sheaths, arranged in 2 rows (Fig. 5H). Notopodial capillaries of first 4 chaetigers longer than those in subsequent chaetigers. Chaetigers 5–14 with stout, bilimbate neurochaetae, distally pointed (Fig. 5D), in 1–2 indistinct rows; notochaetae with distinct sheath (Fig. 5G,I), in 3 rows. From chaetiger 15, notopodial limbate capillaries arranged in tuft; neuropodia with quadridentate hooks without hoods (Fig. 5B), initially with 5–7 hooks in 1 row, often smaller numbers in more posterior chaetigers. Bacillary chaetae as thin, hirsute bristles with brush-like tips (Figs. 2E, 5C), may be exposed on chaetigers 5–7. Ventral sabre chaetae with cryptic ridge from chaetiger 4, appearing granulated near tip under the light microscope (Fig. 5E). Pygidium unknown.

Pigmentation. Specimens usually with dark brownish pigment posteriorly along vertical slit of glandular organs of chaetigers 9–12; most conspicuous on chaetiger 9, gradually fading on the following parapodia (Fig. 5A).

Methyl green staining pattern. In chaetigers 5–7, the chaetal spreader region, in particular the 2 lobes arising from the anterior margin, stainable (Fig. 4B). In addition, on chaetigers 8–14, the neuropodial region and sometimes proximal part of the respective parapodia seen dorsally stainable, but not appearing well defined compared to the surrounding tissue.

Biology. Species occurs in shallow water areas in different sediment types. Gravid specimen found in May (holotype).

Remarks. The species can be readily recognized by the following combination of characters: presence of an occipital antenna, presence of genital pouches from chaetigers 14–15 and chaetal spreaders in chaetigers 5–7 of the “2+3” type with wavy glandular opening.

Japanese specimens recorded as this species may have been incorrectly identified as Spiophanes kroeyeri = Spiophanes kroyeri by Imajima (1991). Since the author has not given information about the appearance of the chaetal spreader and material listed in his article was not available, his identifications require verification.

Etymology. viriosus —Latin for robust, strong; referring to the comparatively large size of the species.

Geographical distribution. Australia: Queensland.