Gesiella jameensis (Hartmann-Schröder 1974)

Gesiella jameensis (Hartmann-Schröder)

Macellicephala (Macellicephala) jameensis Hartmann-Schröder. 1974:76, figs. 1–8.

MATERIAL EXAMINED.—Northeastern Atlantic. Laiwarote, Canary Islands: Jameos del Agua, in lava tunnel, May 1973, Wilckens and Parzefall, collectors, 2 specimens (ZMH 13533). Jameos del Agua, in lava tunnel, November 1973. Wilckens, collector, 2 paratypes (ZMH 13532).

DESCRIPTION.—Length of two paratypes (ZMH 13532) 9–10 mm, width with parapodia 4–5 mm, width with setae 6–7 mm, segments 19. Length of two additional specimens (ZMH 13533) 6–8 mm, width with parapodia 3 mm, width with setae 4–5 mm, segments 18. Body greatly flattened, fusiform, tapered gradually anteriorly and posteriorly, with parapodia about as long as body width (Hartmann-Schröder, 1974, fig. 1). Body colorless to tannish, transparent, with long glassy setae.

Elytra and small rounded elytrophores 9 pairs, on segments 2, 4,5, 7, 9, 11, 13, 15 and 17, with dorsal cirri on segment 18; segment 19, if present, with only remnants of dorsal cirrophores (Figure 36e). Elytra large, oval, transparent, smooth, without tubercles or papillae, slightly notched on lateral sides (Hartmann-Schröder, 1974, fig. 4). Without dorsal tubercles on cirrigerous segments.

Prostomium oval, bilobed, wider than long, without distinct cephalic peaks (Figure 36a–c; Hartmann-Schröder, 1974, fig. 2). Median antenna with large cylindrical ceratophore in anterior notch of prostomium; style long, slender, tapering. Small lateral antennae lateroventral to ceratophore of median antenna, in form of short, spherical bases or ceratophores and minute terminal styles, directed medially and ventrally (Figure 36b). Paired palps slightly thicker and shorter than median antenna. Without eyes. First or tentacular segment fused to prostomium, not visible dorsally; uniramous parapodia lateral to prostomium, without acicular lobes and setae; 2 pairs of tentacular cirri with cylindrical cirrophores and long styles, dorsal pair similar in length to median antenna, ventral pair slightly shorter. Without facial tubercle. Ventral buccal cirri of segment 2 with large cirrophores attached basally on neuropodia, posterolateral to mouth; styles similar to, but shorter than, tentacular cirri, much longer than following ventral cirri (Figure 36c,f); neurosetae similar to those of following segments only more slender.

Parapodia biramous, with notopodia much shorter than neuropodia (Figure 36a,d–h; Hartmann-Schröder, 1974, figs. 5,6). Notopodia small, subconical, with projecting acicular processes. Neuropodia long, with projecting presetal acicular processes, truncate below and diagonally truncate above acicular processes. Notosetae moderate in number, stouter than neurosetae basally, with prominent spinous pockets and blunt tapered tips (Figure 36i). Neurosetae numerous, forming brushlike bundles, long, delicate, flattened, finely toothed along lateral borders, with tapered bare tips (Figure 36j). Dorsal cirri with long cylindrical cirrophores attached posterodorsal to notopodia, with styles long, filiform—some up to half length of body (Figure 36d,e,h; Hartmann-Schröder, 1974, fig. 1). Accessory filamentous sensory organs attached subdistally on dorsal cirrophores, beginning on segment 8, consisting of long delicate filaments and ciliated distal bulbs (Figure 36d,e,h; Hartmann-Schröder, 1974, figs. 1,5–7). Ventral cirri short, tapered. Body with dorsolateral ciliated tufts forming U-shaped patterns, medial to elytrophores and dorsal cirrophores (Figure 36d).

Nephridial papillae indistinct. Pygidium short, rounded, with dorsal anus and pair of anal cirri (styles missing; Figure 36e). Pharynx large, muscular, extending more than half length of body, with 9 pairs of papillae and 2 pairs of jaws.

DISTRIBUTION.—North Atlantic (Canary Islands), in lava tunnels.