Echinomuricea

Namin, Samimi & Ofwegen, Van, 2009, Some shallow water octocorals (Coelenterata: Anthozoa) of the Persian Gulf, Zootaxa 2058, pp. 1-52 : 20-25

Echinomuricea sp. b

( Figs. 13 b, 15c, 16)

Material: RMNH Coel. 38773, five colonies, Hengam Island, coll. K. Samimi Namin; RMNH Coel. 38774, one colony, Kish Island, coll. K. Samimi Namin; RMNH Coel. 38775, four colonies, Kharku Island, depth 15–18 m, 29º 20' 51.1" N, 50º 21' 17.7" E, coll. K. Samimi Namin, 31 March 2007; RMNH Coel. 38776, Farur Island, two colonies, coll. S.A. Mohtarami; RMNH Coel. 38777, one colony, Koninklijke Shell Exploratie en produktie laboratorium, station T1570, off Kuwait, coll. A.J. Keij, 1966.

Description of RMNH Coel. 38776. The depicted colony ( Fig. 13 b) is 7.5 cm high and 5 cm wide. Three stems arise from a common holdfast and branch loosely; branches up to 4 mm wide. Calyces are domeshaped, closely set to each other, and situated all around the branches. The polyps have a collaret and points made up of spindles which are up to 0.40 mm long; the point spindles having one end dentate ( Fig. 16 a–c). The tentacles have small flattened rods, up to 0.10 mm long ( Fig. 16 d).

The calyces have thornscales, up to 0.55 mm long, with a smooth or slightly dentate spine ( Fig. 16 e–f). These thornscales can have a bent or bifurcated spine.

The surface layer of the branches has spindles, many of them with side branches ( Fig. 15 c); the largest up to 0.60 mm long.

The interior of the coenenchyme has a few small radiates, similar in size and shape to those of the above described Echinomuricea species.

Colour. Alive, the colony was red with yellow polyps, preserved, the colony and the sclerites are reddish.

Variability. The specimens from Hengam Island (RMNH Coel. 38773) have thornscales with a much more developed root-like base; the colonies from Kharku Island RMNH Coel. 38775) have thornscales with a much more dentate spine.

Remarks. The species differs from the previously described one in having much thicker branches while the colonies are all much smaller. This striking difference in colony shape is the main reason we consider them to be different species as the sclerites of the two species do not differ much.

Apparently this is one of the more common species in the Persian Gulf (see material).

Figures

FIGURE 16. RMNH Coel. 38776, Echinomuricea sp. b: a, collaret spindles; b – c, point spindles; d, tentacle rods; e-f, thornscales of calyces. Scale at c also applies to one image of a, d – e; scale at f applies to all others.

FIGURE 13. a, RMNH Coel. 38772, Echinomuricea sp. a; b, RMNH Coel. 38776, Echinomuricea sp. b; c, RMNH Coel. 38781, Menella sp. a; d, RMNH Coel. 38782, Menella sp. b; e, RMNH Coel. 38783, Menella sp. c; f, RMNH Coel. 38784, Menella cf. kanisa Grasshoff, 2000; g, RMNH Coel. 38907, Paraplexaura sp. Scales at a and f 2 cm, all others 1 cm.

FIGURE 15. a – b, RMNH Coel. 38772, Echinomuricea sp. a: c, RMNH Coel. 38776, Echinomuricea sp. b; a, branched bodies from surface layer; b, radiates of the subsurface layer; c, spindles of surface layer.