Notophyllum sagamianum Izuka, 1912

Kato, Tetsuya & Pleijel, Fredrik, 2002, A revision of Notophyllum Örsted, 1843 (Phyllodocidae, Polychaeta), Journal of Natural History 36 (10), pp. 1135-1178 : 1166-1168

Notophyllum sagamianum Izuka, 1912

(gure 15)

Notophyllum sagamianu m Izuka, 1912: 210–211, pl. 21, gures 7–9.

Nipponophyllu m sagamianum: Imajima and Hartman, 1964: 68 ; Uschakov, 1972: 172.

Material examined. Two specimens (ZIHU-1877), Aikawa, Sado Island, Japan, ca 70 m, oyster shell, 14–15 May 1996 .

Description. Holotype 43 mm long and 3.5 mm wide for 116 segments according to Izuka (1912). Largest specimen examined 27 mm long and 2.3 mm wide for 89 segments. Body broad, of uniform width, dorso-ventrally attened; dorsum mostly covered by dorsal cirri. Prostomium rounded pentagonal, about as long as wide, with antero-ventral elongation, with a pair of large, rounded eyes with lenses. Length of paired antennae and palps ca half length of prostomium. Median antenna about as long as prostomium, inserted between eyes. Nuchal organs with four to seven long, slender lobes (gure 15A). Number of lobes in smaller specimens (less than 20 mm long) unknown. Proboscis of median length, wider than prostomium (examined in dissection); with single row of discoidal papillae on each side, absent from proximal-most part. Proximal part dorso-laterally with two large rounded papillae on each sides. Proximal and median part of proboscis (>nine-tenths of total length) dorsally and ventrally covered with diOEusely distributed minute, rounded papillae 9–12 m m in diameter; density of minute papillae uncertain. Distal part of proboscis with large oval papillae, 40–90 m m in maximum diameter. Terminal ring smooth, without papillae. Segments 1 and 2 dorsally invisible in larger specimens; smaller specimens unknown. Tentacular cirri of segment 1 reaching ca segment 5 (but see Remarks). Dorsal tentacular cirri of segments 2 and 3 reaching ca segment 7. Ventral tentacular cirri of segment 2 reaching ca segment 6, asymmetrical, distally gradually tapered; posteriorly directed. Segment 2 with ca three compound chaetae arising from ventral tentacular cirrophores. Segment 3 with small neuropodial lobes with ca eight compound chaetae, and small ventral cirri. Dorsal cirri of median segments broad reniform. Tips of dorsal cirri absent in larger specimens; unknown for juveniles. Dorsal cirrophores slightly elongated dorsally, with single aciculae (gure 15B, C). Notopodial capillary chaetae absent. Neuropodial lobes with ca 35 compound chaetae. Ventral cirri reniform. Pygidial cirri unknown. Pygidial papilla present.

Colour. Live specimens white with light bluish tint. Preserved specimens brown. Eyes blackish.

Habitat. From ca 70 m depth, among oyster shells.

Distribution. Known only from Sagami Bay and Sado Island, Japan.

Remarks. Notophyllum sagamianum was described from a single specimen which cannot be located and is considered lost. Following the original description the holotype had short rod-like tentacular cirri on segment 1, and nuchal organs with four elongated lobes. One of two specimens from Sado Island indeed possesses similar rod-like tentacular cirri on segment 1, whereas the second specimen has ‘normal’ long cirri with tapering distal ends. We believe that the special shape of these cirri on segment 1 in some specimens is a result of damage. Further, the specimens from Sado Island have nuchal organs with elongated lobes as in the original description, although with a larger number of lobes. As seen from other Notophyllum , however, the number of lobes varies considerably (gure 1). For these reasons, and in spite of the distance between Sado Island, Sea of Japan and the type locality, Sagami Bay, Paci c coast of central Honshu, we have no doubts that the newly collected specimens are conspeci c with Izuka’s specimen.

Notophyllum sagamianum is similar to N. splendens in having a relatively wide proboscis with a single row of discoidal papillae on each side and dorsally elongated dorsal cirrophores without notopodial capillaries. The main diOEerence between the two taxa is the number of large dorso-lateral papillae on each side of the proximalmost part of the proboscis; in N. sagamianum there are two pairs, whereas in N. splendens there is a single pair. Considering the small number of available specimens, the constancy of these features remains to be veri ed, and our separation of N. sagamiamum and N. splendens is tentative.