Acryptolaria infinita n. sp.

(Figs 11; 30; 31H; Table 12)

TYPE MATERIAL. — NW New Caledonia. MUSORSTOM 4, stn DW 197, 18°51.3’S, 163°21.0’E, 560 m, 20.IX.1985, several stems up to 70 mm high and a few stolonal hydrothecae, on coral, holotype (MNHN-Hy.2009-0162); c. 4 stems on coral fragments, up to 60 mm high, paratype (RMNH-Coel. no. 31509); 3 stem fragments up to 27 mm high in 2 slides, paratypes (RMNH-Coel no. 35004, slide 431; MNCN 2.03 /395) .

OTHER MATERIAL EXAMINED. — NW New Caledonia. MUSORSTOM 4, stn DW 162, 18°35.0’S, 163°10.3’E, 525 m, 16.IX.1985, 1 stem c. 46 mm high (MNCN 2.03/416).

ETYMOLOGY. — The specific name “ infinita ” refers to the exceedingly long hydrothecae. From the Latin “finis”, border, the Latin word “in” indicating without; “infinita” is an adjective in feminine gender.

ECOLOGY AND DISTRIBUTION. — Acryptolaria infinita n. sp. was collected at depths between 525 and 560 m in the Pacific Ocean NW of New Caledonia. It was found epibiotic on coral.

DESCRIPTION

Stems up to 70 mm high, scarcely branched (Fig. 31H), usually with only secondary branches, but up to fourth-order branches have been observed. Branching irregular; branches sinuous, forming a moderate zigzag (Fig. 11A, B).

Hydrothecae alternately arranged in approximately one plane (Fig. 11A, B); tubular (Fig. 11), roughly cylindrical at long free part, but diameter distinctly decreasing basally at adnate basal third; minimum diameter at base. Hydrotheca slightly directed outwards, adnate for approximately one-third of the adcauline wall (adnate/free ratio 0.5). Distal part of hydrotheca predominantly straight. Adcauline wall slightly convex at adnate part, straight or slightly convex at free portion; abcauline wall slightly concave basally, straight at distal part. Hydrothecal aperture circular, oblique and upward directed, forming an angle of c. 45° with long axis of internode. Rim even, frequently with a few short renovations (Fig. 11).

Large nematocysts relatively small and ovoid (Fig. 30).

Coppinia not found.

REMARKS

Acryptolaria infinita n. sp. is unique and easily recognizable by the colony structure, with little branched stems and branches with a moderate zigzag pattern, by the extremely long hydrothecae (the longest known), the shape of that hydrotheca, the relatively large free part of the adcauline hydrothecal wall and the relatively small nematocysts.