Hyalopomatus jirkovi Kupriyanova, 1993a

Kupriyanova, Elena K., Bailey-Brock, Julie & Nishi, Eijiroh, 2011, New records of Serpulidae (Annelida, Polychaeta) collected by R / V " Vityaz " from bathyal and abyssal depths of the Pacific Ocean, Zootaxa 2871, pp. 43-60 : 56-57

Hyalopomatus jirkovi Kupriyanova, 1993a

( Fig. 5 A–B, H)

Hyalopomatus jirkovi Kupriyanova, 1993a: 147 –148, fig. 1.

Material examined. Type material. SIO: R/V “ Vityaz ” Stn. 5593, 45 °38’N, 152°02’E, 1050 m, 12 Aug 1966 (holotype and paratype).

Newly examined material. SIO: R/V “ Vityaz ” Stn. 4131, 55 º47.6’N, 145º19.7’W, 3949 m, trawl, 9 Nov 1958 (4 specs).

Description. Tube: Tubes white, smooth, attached to the Cidaris throughout its length, circular in cross-section, some indication of interruptions in calcium carbonate secretion (see Sanfilippo 2009) along the tube.

Branchial crown: 8–10 pairs of radioles, not joined by inter-radiolar membrane. Bases of branchial radioles short. Branchial eyes not visible in preserved material. Stylodes absent.

Peduncle: inserted as 1st dorsal radiole on left side of crown, thin, smooth, circular in cross-section. Constriction present. Pair of lateral wings proximal to opercular bulb and pseudoperculum absent.

Operculum: semi-transparent elongated vesicle with slightly differentiated darker distal cap ( Fig. 5 H).

Collar and thoracic membranes: collar four-lobed, with ventral lobe additionally sub-divided into two round lobes by a deep incision; ventro-lateral lobes twice as long as latero-dorsal lobes ( Fig. 5 A, B). Thoracic membranes reaching up to 3rd chaetiger, of even width throughout ( Fig. 5 A, B).

Thorax: with six thoracic chaetigers, five of which uncinigerous ( Fig. 5 A, B). Collar chaetae simple capillaries and special fin-and-blade chaetae, with wide blade continuing without a gap in proximal fin made of numerous small teeth. Remaining notochaetae with short wide distal limbate blade. Apomatus chaetae absent. Thoracic uncini rasp-shaped, with about 20 teeth in profile view, arranged in 3–4 transverse rows, and with elongated and flattened anterior peg (SEM details of peg structure not available).

Abdomen: abdominal uncini similar to thoracic uncini but smaller with about 20 teeth in profile view. Straight, almost capillary (distal limbation very narrow) abdominal chaetae (SEM details not available).

Colour: unknown.

Remarks. This is the second record of this species previously known only from two specimens (the type material) collected from the Kurile-Kamchatka Trench. Hyalopomatus jirkovi clearly differs from all described species of Hyalopomatus by the structure of the collar with ventral lobe sub-divided into two lobes by deep incision at midline.

Distribution. Kurile-Kamchatka Trench, Gulf of Alaska, 1050–3949 m.

Figures

FIGURE 5. Line drawings of Hyalopomatus jirkovi. A—dorsal and B—lateral views of the holotype, H—operculum of holotype (redrawn from Kupriyanova 1993 a). Line drawings of Hyalopomatus sikorskii. C, D—opercula of the specimens from R / V “ Vityaz ” Stn. 4131, E—dorsal and F—lateral views of the holotype (redrawn from Kupriyanova 1993 a), G—operculum of the holotype (redrawn from Kupriyanova 1993 a). Bathyvermilia eliasoni, I—fragment of the tube from R / V “ Vityaz ” Stn. 3150 (Bailey-Brock). Filogranula stellata, J—fragment of the tube from R / V “ Vityaz ” Stn. 6348 - 2 (Bailey-Brock). Scale: A, B— 1 mm, C, D— 0.2 mm, E, F— 0.5 mm, G— 0.2 mm, H— 0.3 mm, I— 1 mm, J— 3 mm.