Spiophanes uschakowi Zachs, 1933

Blank, Miriam, 2009, Spiophanes norrisi sp. nov. (Polychaeta: Spionidae) — a new species from the NE Pacific coast, separated from the Spiophanes bombyx complex based on both morphological and genetic studies, Zootaxa 2278, pp. 1-25 : 15-20

Spiophanes uschakowi Zachs, 1933

( Fig. 7 )

Spiophanes uschakowi Zachs, 1933: 130 .

? S. bombyx : – Imajima, 1991: 128 –132, figs 8–9. – Okuda, 1937: 222 –223, figs 3–4.

Type material. SYNTYPE: Russia, Sea of Japan, Peter the Great Bay, Station 70, 1 specimen (Zool. Inst. RAS 1/25826).

Non– type material. Spiophanes cf. uschakowi : NW Pacific Ocean: Japan: Chiba Prefecture: off Tomizu 35°21.200' N 139°48.100' E, 2- VIII-2008, 1 specimen ( ZMH P- 25866), Mie Prefecture 35° 01.010' N 136°42.350' E, 14- VI-2007, 8 specimens ( ZMH P- 25867), Wakayama Prefecture: Hidaka Port 33°52.280' N 135°09.175' E, 13- VI-2008, 1 specimen ( ZMH P- 25868).

Description based on single syntype from Zool. Inst. RAS 1/25826. Syntype incomplete anterior fragment of about 35 chaetigers, 0.8 mm in width. Prostomium broad anteriorly, subtriangular, with long, digitiform anterolateral horns ( Fig. 7 A). Occipital antenna absent. Eyes absent. Dorsal ciliated organs starting posterior to the prostomium as continuous, slightly diverging ciliated bands continuing to the end of chaetiger 2 ( Fig. 7 A), not well preserved; additional metameric patches posterior to chaetiger 2 not discernable. Peristomium moderately developed. First parapodium oriented dorsally; postchaetal lamellae subulate, slightly longer in the notopodium than in the neuropodium ( Fig. 7 A). Parapodia of chaetigers 2–4 shifted from dorsal to dorsolateral position; postchaetal lamellae subulate; longer in the notopodia than in the neuropodia; postchaetal lamellae continuously decreasing in size from chaetiger 1 to 4. From chaetiger 5 to the end of the fragment, all parapodia lateral. Chaetigers 5–8 with subulate to subtriangular postchaetal notopodial lamellae, lamellae shorter than in preceding chaetigers; neuropodial postchaetal lamellae absent ( Fig. 7 B). From chaetiger 9, notopodial postchaetal lamellae subulate to cirriform with broad base; neuropodial lamellae absent ( Fig. 7 B).

Chaetal spreader “0+1 type ” with semicircular opening well developed on chaetigers 5, 7, and 8; opening of glandular organ on chaetiger 6 not observable by means of light microscopy; on chaetigers 9–14 openings are lateral vertical slits ( Fig. 7 B). Ventrolateral intersegmental pouches absent. Dorsal ciliated crests of considerable size present from chaetiger 3 to the end of the fragment ( Fig. 7 A, B).

Chaetiger 1 with one stout, crook-like chaeta in each neuropodium; remaining chaetae all capillaries with narrow sheaths; notopodial chaetae smooth, neuropodial chaetae appearing granulated when viewed with light microscopy; arrangement of chaetae difficult to observe (most likely notochaetae arranged in a tuft and neurochaetae in rows). Chaetigers 2–4 with smooth capillaries with narrow sheath in notopodia; neuropodial chaetae granulated with narrow sheath; arrangement of chaetae difficult to observe (most likely as described for chaetiger 1). In all following chaetigers notochaetae are smooth sheathed capillaries. Nature of neuropodial chaetae in chaetigers 5–14 unknown (see Remarks). Neuropodial quadridentate hooks with partially reduced hood ( Fig. 7 C) first present from chaetiger 15; 6–7 hooks arranged in one row. Stout, granulated chaeta (= sabre chaeta) in inferiormost position in the neuropodium, first present from chaetiger 10, continuing to end of fragment. Nature of pygidium unknown.

Additional information based on examination of specimens from Japan (here referred to as S. cf. uschakowi ). Specimens 0.4–0.5 mm wide, all anterior fragments, longest fragment with 36 chaetigers. Prostomium broad anteriorly, subtriangular, with long, digitiform anterolateral horns. Occipital antenna absent. Two pairs of black eyes present; anteriormost pair further apart. Dorsal ciliated organs starting posterior to the prostomium as continuous ciliated bands extending to the end of chaetiger 2, thereafter as pair of segmental ciliated patches, increasing in size, eventually becoming pairs of straight short ciliated bands continuing to about chaetiger 10; after chaetigers 10–13 metameric ciliated patches comma-shaped, from between chaetigers 13–14 ciliated patches as bands of slightly oblique orientation; from between chaetigers 14–15 as short, almost transverse bands; same type of ciliated band in subsequent chaetigers; after application of Shirlastain A additional thin transverse ciliary bands observed between metameric ciliated patches; shape of metameric dorsal ciliated organs in further posterior segments not ascertainable.

Peristomium moderately developed. First parapodium oriented dorsally; postchaetal lamellae subulate, only slightly longer in the notopodium than in the neuropodium. Parapodia of chaetigers 2–4 shifted from dorsal to dorsolateral position; postchaetal lamellae subulate, longer in the notopodia than in the neuropodia; postchaetal lamellae continuously decreasing in size from chaetigers 1 to 4. From chaetiger 5 to the end of the fragment, all parapodia lateral. Chaetigers 5–8 with subulate to subtriangular postchaetal notopodial lamellae, lamellae all of the same size and only slightly shorter than in chaetiger 4; neuropodial postchaetal lamellae absent. From chaetiger 9, notopodial postchaetal lamellae subulate with broad base and slender filiform tip; neuropodial lamellae absent.

Chaetal spreader “0+1 type ” with semicircular opening well developed on chaetigers 5, 7, and 8; opening of glandular organ on chaetiger 6 not observed with light microscopy; on chaetigers 9–14 openings as lateral vertical slits. Ventrolateral intersegmental pouches absent. Dorsal ciliated crests present from chaetiger 3 to the end of fragments.

Chaetiger 1 with one stout, crook-like chaeta in each neuropodium; remaining chaetae all capillaries with narrow sheaths; notopodial chaetae smooth, neuropodial chaetae appearing granulated when viewed with light microscopy; most likely notochaetae arranged in a tuft and neurochaetae in two rows. Chaetigers 2–4 with smooth capillaries with narrow sheath in neuro- and notopodia; arrangement of chaetae most likely as described for chaetiger 1. In all following chaetigers notochaetae smooth narrowly sheathed capillaries and neurochaetae granulated stout capillaries with narrow sheath. Neuropodial quadridentate hooks with partially reduced hood first present from chaetiger 15; 6–7 hooks arranged in one row. Stout, granulated chaeta (= sabre chaeta) in inferiormost position in the neuropodium first present from chaetiger 9 or 10. Nature of pygidium unknown.

Type locality. Northern Sea of Japan: Peter the Great Bay.

Pigmentation. Syntype dark brown; remnants of even darker pigment in neuropodia of chaetigers 9–14 (area posterior to the vertical lateral slits) ( Fig 7 B). In specimens from Japan orange pigment in neuropodia of chaetigers 10–14; hints of orange pigment in neuropodia of chaetigers 9 and 15 in some specimens.

Methyl green staining pattern. Inconspicuous in the syntype (also due to strong dark brown pigmentation of the examined syntype) and also inconspicuous in specimens from Japan.

Biology. Unknown.

Remarks. The original description by Zachs (1933) was as follows: “ Postchaetal notopodial lamellae of chaetigers 1–8 foliaceous, later becoming rather cirriform. Dorsal pattern of double horizontal stripes on anterior segments. Dorsal crest absent on the first chaetiger. Hooks similar to those in S. bombyx . In 10 posterior segments 1–2 long stout notochaetae.” The syntype examined in the course of this study was an anterior fragment of 35 chaetigers. The specimen is of dark brown colour, which affected observation under the light microscope. Moreover, the specimen is very brittle and hence extensive dissection of parapodia was avoided and only a few neuropodial hooks were removed. For that reason detailed information on chaetal characters of the syntype is limited. However, preliminary results from examination of specimens from Japan are provided in this study. Based on those results, the differences between S. uschakowi and other Spiophanes species are as follows:

S. uschakowi is easily distinguished from all other Spiophanes species known from coastal waters of the western Pacific by its strikingly long anterolateral horns; the chaetal spreaders of “0+1 type ” with an almost semicircular opening well developed on chaetigers 5, 7, and 8; the dorsal ciliated organs starting as two short continuous bands extending to the end of chaetiger 2 followed by metameric patches in a species-specific pattern as described above; the first presence of sabre chaetae not earlier than chaetiger 9; and the presence of partially hooded hooks in the neuropodia of the posterior body region. For differences with S. anoculata from deep waters of the North Pacific Ocean, off California, see remarks under S. norrisi . Reliable identification of S. uschakowi is currently possible only if based on observation of the dorsal ciliated organs ( Tab. 2). All other character states overlap with character variation in S. norrisi . The species description of S. uschakowi has to be enhanced as soon as new material from the type locality becomes available. Also, it is necessary to investigate the possible synonymy of S. bombyx from Japan (see descriptions by Okuda 1937 and Imajima 1991) with S. uschakowi .

Geographical distribution. Known from the type locality in the Sea of Japan, NW Pacific Ocean; elsewhere uncertain.

Figures

FIGURE 7. Spiophanes uschakowi Zachs, 1933: A. Anterior end, dorsal view. B. Chaetiger 5 – 12, lateral view; arrow indicates simple vertical opening of glandular organ in chaetiger 11. C. Neuropodial hooks with reduced hood from chaetiger 19. — All Syntype, RAS 1 / 25826. Scale: A, B 0.5 mm; C 10 µm.