Trimuricea tuberculosa n. sp.

(Figs. 21 d, 28–29, 32b)

Material: Holotype, RMNH Coel. 39318, piece of colony, Persian Gulf, Iran, Larak Island, 26° 53′ 15″ N, 56° 23′ 36″ E, 14–16 m depth, coll. K. Samimi-Namin, 5 December 2007. Paratype, RMNH Coel. 41386, Strait of Hormuz, Oman, Musandam, deep purple, 26.362347° N, 56.524719° E, 10–25 m depth, coll. K. Samimi-Namin, 9 May, 2011.

Description. The holotype is a piece of colony, about 25 cm high and 15 cm wide, which is branched in one plane and has many anastomoses forming a network (Fig. 21 d). The calyces are dome shaped, closely set to each other and situated all around the branches. They are up to 0.5 mm high and 1 mm wide.

The points have triradiates (Fig. 28 a), along with curved, hockeystick or boot-shaped sclerites, or spindles (Fig. 28 b), 0.15–0.37 mm long. The upper ray of the triradiates and the upper part of the spindles is echinulate or tuberculate for up to 0.23 mm. The collaret spindles are not markedly flattened and are 0.25–0.44 mm long (Fig. 28 c); the middle part of the convex side tends to be more tuberculate than the concave side and both the ends. The concave sides have relatively evenly distributed tubercles. These polyp sclerites have strong tuberculation. A few tentacle scales are present, up to 0.05 mm long (Fig. 28 d).

The calyces have thornscales, 0.25–0.40 mm long, with a thick, heavily warted base, and one or more smooth or echinulate thorns up to 0.17 mm long (Fig. 29 a).

The coenenchyme has spindles, 0.30–0.70 mm long, with complex (Fig. 29 b) and simple tubercles (Fig. 29 c). In the larger spindles the warts are very densely arranged. A few of these spindles superficially resemble unilateral spinose spindles. There are also some crosses and triradiates present and a few of the spindles with simple tubercles are branched (Fig. 29 c); irregular shaped sclerites are also present, some with one or more thorns (Fig. 29 d).

Colour. The live colony was white-yellowish, with purple polyps (Fig. 32 b, paratype). Preserved it is brown. All sclerites are colourless.

Etymology. The specific epithet is derived from the Latin noun tuberculum (a small swelling, bump, or protuberance). It refers to tubercles densely covering the sclerites.

Remarks. This species mostly resembles T. merguiensis n. sp., but differs from that species in having more strongly tuberculated sclerites and an absence of spindles with one blunt and one sharp end. This is the species in Trimuricea with the highest amount of dense, complex tuberculation in all types of sclerites.

The paratype RMNH Coel. 41386, has slightly shorter, less tuberculate spindles up to 0.5 mm long. It has more spindles with thorns that resemble unilaterally spinose spindles than the holotype.