Cryptolarella abyssicola

Cryptolarella abyssicola (Allman, 1888)

(Fig. 3C–E)

Cryptolarella abyssicola — Marques et al., 2005: 711 –719, fig. 1 (synonymy)

Material examined. 51416#1, one stem fragment c. 14 mm long, no gonothecae; 52602#13, four stem fragments up to 23 mm long, with gonothecae; 52701#6, three stems up to 70 mm high, with gonothecae; 52701#48, a few fragments up to 33 mm long, no gonothecae.

Description. Polysiphonic stems, up to 70 mm high. Hydrorhiza rhizoidal, quite robust, formed by a few, basally polysiphonic stolons. Hydrothecae arising in an indefinite pattern. Hydrotheca (Fig. 3C–D) tubular, diameter roughly constant throughout its length. Hydrotheca bent outwards at distal part. Free portion of hydrotheca highly variable. Hydrothecal aperture circular, rim even, frequently with many renovations.

Gonothecae solitary, resting on stem and branches. Gonotheca elongate, with large, circular, distal aperture (Fig. 3E). Gonothecal wall with fine transversal striation (Fig. 3E).

Only one category of microbasic euryteles observed.

Measurements (in µm). Hydrotheca: diameter at aperture 140–180. Gonotheca: length, 2100–2400, diameter at aperture 360–400. Cnidome: microbasic euryteles, 8– 9 x 3–3.5.

Remarks. See Marques et al, (2005) for a revision and wide discussion on the genus Cryptolarella, as well as for a re-description of the type material of the species.

Ecology and distribution. This is a deep-water species, found at depths from 200 (Millard 1975) to 6328 m (Vervoort 1972) in scattered records from the Antarctic, Atlantic, Pacific and Indian oceans (cf. Marques et al. 2005). The present material comes from the Porcupine Seabight and the Porcupine Abyssal Plain, collected at depths from 2770 to 4853 m, with gonothecae in May.