Acryptolaria encarnae n. sp.

(Figs 8; 30; 31E; Table 9)

TYPE MATERIAL. — Loyalty Islands. MUSORSTOM 6, stn CP 464, 21°02.30’S, 167°31.60’E, 430 m, 21.II.1989, 1 stem c. 70 mm high, holotype (MNHN-Hy.2009- 0160); 1 stem 50 mm high, paratype (RMNH-Coel. no. 31506).

OTHER MATERIAL EXAMINED. — Norfolk Ridge. BIOCAL 1, stn DW 66, 24°55.435’- 24°54.849’S, 168°21.678’- 168°21.995’E, 515- 505 m, 3.IX.1985, 1 unbranched fragment c. 13 mm long in slide (MNCN 2.03/393).

ETYMOLOGY. — The species name encarnae is a dedication to Encarna Sancho Aguilar, wife of the first author. The name is a noun in female genitive.

ECOLOGY AND DISTRIBUTION. — Acryptolaria encarnae n. sp. was collected at depths between 430 and 515 m in both the Loyalty Islands area and at the Norfolk Ridge.

DESCRIPTION

Stems up to 70 mm high, strongly polysiphonic and with dish-shaped hydrorhiza (Fig. 31E). Branching scarce and irregular; primary branches originating at basal part of stem, long, straight, upward directed and usually unbranched. 70 mm high stem of holotype with first 9 mm unbranched and tortuous, then with a primary branch of stronger development than main stem. The other stem in the sample (paratype) could actually be a detached primary branch of the main stem. The primary branch of the holotype gives rise to three secondary branches; of these, one forms two third-order branches, whereas the other two are unbranched, one is even 45 mm long. Main stem giving rise to two extra primary branches, the basal one forming two secondary branches. Branches straight (Fig. 8A, B).

Hydrothecae alternately arranged in approximately one plane (Fig. 8A, B), cylindrical (Fig. 8), diameter decreasing only slightly at basal part. Hydrothecae gently curved outwards, adcauline wall convex throughout, abcauline wall concave. They are adnate for almost two-thirds of their adcauline length (adnate/free ratio 1.8). Hydrothecal aperture circular and directed outwards, almost parallel to long axis of branch (Fig. 8); rim even. Some hydrothecae with dish-shaped operculum.

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

Coppinia not found.

REMARKS

Acryptolaria encarnae n. sp. is clearly recognizable by the colony structure, with long, straight and little branched primary branches, and by the shape of the hydrothecae which are almost cylindrical throughout and gently curved outwards.

The material from BIOCAL 1 stn DW 66 has slightly larger nematocysts (cf. Table 9) and the hydrothecae are less strongly directed outwards (Fig. 8E).

Acryptolaria encarnae n. sp. resembles A. abies in the straight branches and general shape of the hydrotheca but the two species are easily distinguishable because in A. abies the hydrothecae are much smaller (cf. Peña Cantero et al. 2007: table I) as also applies to the nematocysts (11.2 × 4.6 µm in the lectotype).