Alcyonium grandis Casas et al., 1997

Ofwegen, Van, 2007, The genus Alcyonium (Octocorallia: Alcyonacea: Alcyoniidae) in Chile, Zootaxa 1607, pp. 1-19 : 7

Alcyonium grandis Casas et al., 1997

( Figs. 1 b–c, 5, 11)

Alcyonium grandis Casas et al., 1997: 304 , figs. 5–7.

Material: RMNH Coel. 34936, fragment of colony, Chile, Islas Diego Ramírez/Drake Passage (approx. 56°30' S; 68°45' W), depth 1800 m, coll. Claudio Vera, 2001; ZSM 20061187, fragment of colony, South Georgia, depth 1200 m, coll. Eugenio Olivares, September 2003.

Description of RMNH Coel. 34936. The colony is membranous, about 1.5 cm long and 1cm wide ( Fig. 1 c).

Polyps are evenly distributed over the colony. Calyces are dome shaped and all polyps are partly retracted with tentacles withdrawn.

Anthocodiae have a collaret of a few irregularly arranged rows of spindles; the points have many spindles. In order to preserve as much as possible of the fragment no microscope slides were made for drawing the anthocodial sclerite arrangement. The collaret spindles are up to 0.55 mm long, with spines and prominent simple tubercles ( Fig. 5 a–b). Points have spindles similar to those of the collaret, with clubs present distally, up to 0.30 mm long ( Fig. 5 c). The tentacles are without sclerites.

The surface layer of calyces and membrane has exclusively capstans, 0.10–0.15 mm long ( Fig. 5 d, h). The interior has tuberculated spindles ( Fig. 5 f–g, i), the longest present in the calyces, up to 0.40 mm long. Some of these spindles are club-like ( Fig. 5 e), but real clubs were not observed.

Colour. The preserved colony is white, and all sclerites are colourless.

Habitat, distribution and abundance. The species occurs in South Georgia, and was collected only once in Chile, at 1800 m depth.

Remarks. ZSM 20061187 is also only a fragment, but a large part of that colony has been photographed, showing more of its colony shape ( Fig. 1 b). The species was originally described from off Shag Rocks and South Georgia, at 152–335 m depth ( Casas et al., 1997: 308). All six colonies of the type series showed colonies with numerous lobes, the largest colony, the holotype, even reaching 16.5 cm in height. It is remarkable that the present material forms encrusting sheets. However, comparison of sclerites showed the present material in close agreement with A. grandis , and therefore we identified it as this species despite the big difference in colony shape.

The species differs from all the other species in Chile by the total lack of clubs in the coenenchyme.

Figures

FIGURE 5. Alcyonium grandis Casas et al., RMNH Coel. 34936; a – b, collaret spindles, c, point clubs; d, capstans of calyces; e, club-like spindles of calyces; f – g, spindles of calyces; h, capstans of membrane, i, spindles of membrane. Scales 0.10 mm, that at a also applies to f, that at c to all others.

FIGURE 1. a, RMNH Coel. 34935, holotype Alcyonium glaciophilum n. sp.; b, A. grandis ZSM 20061187; c, A. grandis RMNH Coel. 34936; d, two syntypes of A. haddoni; e, A. haddoni RMNH Coel. 34937; f, A. haddoni RMNH Coel. 34938; g, RMNH Coel. 34942, holotype of A. jorgei; h, RMNH Coel. 34946, holotype of A. roseum; i, RMNH Coel. 34948, holotype of A. yepayek. Scales 1 cm, that at c only applies to c, that at h only to h.