Acryptolaria profunda n. sp.

(Figs 23; 30; 32F; Table 24)

TYPE MATERIAL. — Loyalty Islands. MUSORSTOM 6, stn DW 422, 20°26.20’S- 166°40.31’E, 257 m, 16.II.1989,1 stem c. 20 mm high, holotype (MNHN-Hy.2009-0170).

ETYMOLOGY. — The specific name profunda refers to deep hydrothecae, the Latin “profundum” meaning deep. It is an adjective in feminine gender.

ECOLOGY AND DISTRIBUTION. — Acryptolaria profunda n.sp. was collected at a depth of 257 m in the Loyalty Islands.

DESCRIPTION

Stem basally truncate, 20 mm high (Fig. 32F), with only two short, alternate primary branches with a slight zigzag structure (Fig. 23A, B), obscure at the strongly polysiphonic basal part where the stem seems to be straight. Branches slightly widening at the point where the hydrotheca becomes free (Fig. 23A, B).

Hydrothecae alternately arranged in one plane (Fig. 23A, B), tubular, roughly cylindrical in the free portion (Fig. 23); diameter decreasing at basal adnate part, minimum diameter at base. Hydrotheca strongly curved outwards, but distal part basically straight. Hydrotheca free over half of its adcauline length (adnate/free ratio 0.8). Adcauline wall convex at basal half, straight at distal half; proximal part of abcauline wall concave, but straight at distal half. Hydrothecal aperture circular, oblique and directed upwards, forming an angle of c. 30° with the long axis of branches. Some hydrothecae without renovations, but others with up to nine.

Large nematocysts relatively large and fusiform (Fig. 30).

Coppinia not observed.

REMARKS

Acryptolaria profunda n. sp. has certain characters in common with A. laertesi n. sp. as for instance the general shape of the hydrothecae, though these are smaller in the latter and a larger proportion of the adcauline hydrothecal wall is adnate. Both species are also distinguishable by the size of the nematocysts, that are much larger in A. laertesi n. sp. (29.5 × 7.2 µm).