Trimuricea aff. reticulata (Thomson & Simpson, 1909)

(Figs. 31a, 32 –33)

Echinomuricea reticulata Thomson & Simpson, 1909: 206 .

Material: RMNH Coel. 38785, one specimen, Farur Island, coll. S.A. Mohtarami.

Description. The colony is 16 cm high and 22 cm wide, branched in one plane, and many anastomoses form a network (Fig. 31a). Calyces dome shaped, 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 0.35 mm long; triradiates are also present in the polyps (Fig. 32).

The coenenchyme has thornscales (Fig. 33a), up to 0.40 mm long, and spindles up to 0.60 mm long (Fig. 33b); occasionally one of these spindles has a short spine. The smallest spindles have simple tubercles, the larger ones also complex tubercles.

Colour. Alive, the colony was reddish-purple, preserved it is brown. All sclerites are colourless.

Remarks. Gordon (1926: 515) recognized four species when she erected the genus Trimuricea: T. andamanensis (Thomson & Simpson, 1909); T. reticulata (Thomson & Simpson, 1909); T. africana Gordon, 1926; and T. merguiensis Gordon, 1926 . Later on Grasshoff (1999: 48–49) added a fifth species, T. caledonica . Of these T. andamanensis should be considered a species of Echinogorgia as Thomson & Simpson’s picture of sclerites (Pl. 8 Fig. 2) suggests. T. africana differs from the present material in lacking anastomoses, and T. merguiensis differs in having “clubbed spindles in the coenenchyme”, i.e. spindles which are wider at one end. T. caledonica has thornscales with much shorter spine (Grasshoff 1999: Fig. 81; Fabricius & Alderslade 2001: 196). T. reticulata resembles the present material, the thornscales and spindles look similar, although it should be considered that the few drawings of sclerites presented in the literature (Thomson & Simpson, 1909: Pl. 8 Fig. 6; Grasshoff 1999: Fig. 80) are all a bit schematic, and too few were given to obtain certainty about the amount of variation of these sclerites. Thomson & Simpson reported their specimens had polyp spindles up to 0.7 mm long, twice as long as those of the present Persian Gulf specimen. According to us a difference like that is big enough to establish a new species, however, Grasshoff depicted much smaller polyp sclerites with his re-examination of the holotype (up to 0.28 mm long). Because of these uncertainties in the existing literature and pending a new re-examination of the type material we decided to identify the present material as T. aff. reticulata .