Spiophanes sp. A

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 : 135-137

Spiophanes sp. A

Material. AUSTRALIA, VICTORIA, 53 km S of Cape Conran, 38°8'S 148°39'E, in 750 m, May 1969, 1 specimen (AM W13019).

Other species examined. Spiophanes lowai Solís-Weiss, 1983 , NORTH PACIFIC OCEAN: MÉXICO, Sinaloa, Sinaloa coast S of Mazatlan, 23°38.3'N 106°55.3'W, in 37 m, 25 Aug 1981, 1 paratype (USNM 80467).

Description. Specimen incomplete, with 25 chaetigers; 1.8 mm wide, about 8 mm long. Body slender, subcylindrical. Prostomium broad anteriorly, bell-shaped, with distinct anterolateral projections. Occipital antenna long, slender. Eyes absent. Nuchal organs as two ciliated bands along dorsum; starting posterior to prostomium as two parallel, dorsolateral lines to chaetiger 6, bands converge between chaetigers 7–9, continuing posteriorly as two close parallel bands middorsally to chaetiger 15. Peristomium well developed. Parapodia of chaetiger 1 dorsolateral; postchaetal lamellae cirriform, neuropodial more robust. Postchaetal notopodial lamellae of parapodia of chaetigers 2–4 long, cirriform, neuropodial lamellae shorter, subulate in chaetigers 3 and 4. Chaetigers 5–8 with short, rounded notopodial and reduced neuropodial postchaetal lamellae. From chaetiger 9, notopodial lamellae subtriangular with short slender tip, in posterior chaetigers slender tip elongate; neuropodial lamellae reduced. Chaetal spreader “0+1 type” with well-developed semicircular glandular openings on chaetigers 5–7; glandular opening on chaetiger 8 absent; glandular organ of chaetigers 9–14 opens as lateral, vertical slit. First fully developed ventrolateral intersegmental genital pouches present between chaetigers 14–15. Dorsal ciliated crests from chaetiger 20. Chaetiger 1 usually with 1 stout, crook-like chaetae in neuropodium; remainder of chaetae capillaries; notochaetae arranged in tuft; neurochaetae in 2 rows. Notochaetae of chaetigers 2–4 with simple capillaries and capillaries with narrow sheaths, arranged in tuft; neurochaetae capillaries with narrow sheaths, arranged in 2 rows, anterior row appearing granulated. Notopodial capillaries of chaetigers 1–4 longer than those of subsequent chaetigers. Chaetigers 5–14 with stout bilimbate neurochaetae, distally pointed, arranged in 1–2 indistinct rows; notochaetae with distinct sheath, in 3 rows. From chaetiger 15, limbate capillaries in notopodia, their sheaths becoming narrower, notochaetae in tuft; neuropodia bearing quadridentate hooks without hoods, initially with 6–7 hooks in 1 row. Bacillary chaetae not emergent. Ventral sabre chaetae with cryptic ridge from chaetiger 4, appearing granulated distally. Pygidium unknown.

Pigmentation. Brownish pigment from chaetigers 9–14; encompasses entire parapodium except for distal parts of postchaetal notopodial lamellae and distal-most region of neuropodium. Brownish pigment in notopodial postchaetal lamellae of chaetigers 15–19.

Methyl green staining pattern. Pigmented areas take up stain most intensely.

Remarks. The described specimen, an anterior fragment, is in good condition. It is clearly different from all other species in the Australian museum collections in presenting the following character combination: presence of an occipital antenna, chaetal spreader of “0+1 type” with welldeveloped semicircular glandular opening on chaetigers 5– 7, presence of intersegmental genital pouches from between chaetigers 14–15, and pigmented parapodia on chaetigers 9–14. Among Australian species, it is most similar to S. viriosus n.sp., which also has an occipital antenna on a bellshaped prostomium with short anterolateral projections and intersegmental genital pouches from between chaetigers 14– 15. However, Spiophanes sp. A clearly differs from S. viriosus in having a chaetal spreader of the “0+1 type” with semicircular glandular opening rather than a chaetal spreader of the “2+3 type” with wavy glandular opening.

In addition, Spiophanes sp. A has a pigmented region on chaetigers 9–14 and pigmented notopodial lamellae on chaetigers 15–19 instead of having a smaller pigmented region in neuropodia of chaetigers 9–12 as present in S. viriosus . Considering species known world-wide, the specimen closely resembles a paratype of S. lowai (USNM 80467), described from the Pacific coast of México. Only minor differences concerning the pigmentation of these two specimens can be found, but it also has to be mentioned that the nuchal organs cannot be observed in the specimen from México since the cuticula of the dorsum is damaged. However, all other characters appear to match. The problem is that several significant characters of the examined S. lowai paratype are different from the species description of S. lowai : the occipital antenna is described as small rather than large, brown pigment is supposed to occur from chaetigers 10–15 rather than 9–14, and sabre chaetae to begin on chaetiger 5 rather than 4. Intersegmental genital pouches Solís-Weiss (1983) describes to begin on chaetiger 15 rather than between chaetiger 14 and 15. Apart from these discrepancies, it also has to be stressed that the differentiation between S. kroyeri and S. lowai is also problematical. Under these circumstances it did not seem to be appropriate to assign the single Australian specimen to either a new or a known species.