Trimuricea merguiensis Gordon, 1926

Samimi-Namin, Kaveh & Van Ofwegen, Leen P., 2016, A revision of Trimuricea Gordon, 1926 (Cnidaria: Octocorallia: Plexauridae) with the description of six new species, Zootaxa 4105 (1), pp. 1-44 : 22-23

Trimuricea merguiensis Gordon, 1926

( Figs. 16–18 )

Trimuricea merguiensis Gordon, 1926: 518 , fig. 5j.

Material: Holotype, BMNH 1933.5.3.104, Moscos, Mergui Archipelago, coll. J.A. Thomson, holotype marked 10a; fragment of holotype BMNH 1925.11.24.23, loc. 54, Mergui Archipelago, February–March 1907.

Description (colony shape after Gordon 1926). The holotype is 13 cm high and 8 cm wide, branched in one plane, and many anastomoses are present ( Fig. 16 a). The main stem, which has a diameter of 4 mm, divides in two main branches shortly above the base. The branches have an average diameter of 2 mm. The calyces are dome shaped, closely set to each other, and situated all around the branches.

The points have triradiates ( Fig. 17 a), along with curved, hockeystick or boot-shaped sclerites or spindles ( Fig. 17 b), 0.15–0.30 mm long. The upper ray of the triradiates and upper part of the spindles is slightly echinulate for up to 0.20 mm. The collaret spindles are 0.25–0.40 mm long ( Fig. 17 c); the middle part of the convex side is slightly more tuberculate than the concave side and both the ends. The polyp sclerites have strong tuberculation. A few tentacle scales are present, up to 0.10 mm long ( Fig. 17 d).

The calyces have thornscales, 0.10–0.40 mm long, with an echinulate or tuberculate thorn up to 0.15 mm long and complexly branched roots ( Figs. 18 a). Several of these thornscales have more than one thorn.

The coenenchyme has spindles, 0.30–0.65 mm long, with simple and complex tubercles ( Fig. 18 b). Several of these spindles have one blunt end, many are markedly robust.

Colour. The preserved colony is grey. All sclerites are colourless. There is no information about the colour of the colony and polyp.

Remarks. Figure 16 a shows the holotype, a label is attached to it marked 10a (removed in the Figure 16 a).

Figure 16 b is a second specimen also stored under BMNH 1933.5.3.104. Gordon mentioned a single specimen in her publication, and therefore we assume the second specimen was added after her description and is not type material. Gordon reported the holotype to be 13 high and 11 cm wide, probably due to subsequent sampling (i.e. BMNH 1925.11.24.23) the colony is now only 8 cm wide.

Gordon did not describe the sclerite arrangement in the polyps.

This species mostly resembles Trimuricea tuberculosa n. sp. but differs in having a few spindles with one blunt end (also observed by Gordon), and the spindles with less dense tuberculation. In addition T. tuberculosa has some spindles with a few thorns, and irregular shaped sclerites are occasionally also present in the coenenchyme.

Figures

FIGURE 17. The polyp sclerites of T. merguiensis Gordon, 1926, holotype, BMNH 1933.5.3.104: a, point triradiates; b, point spindles; c, collaret spindles; d, tentacle scale.

FIGURE 18. Sclerites of T. merguiensis Gordon, 1926, holotype, BMNH 1933.5.3.104: a, calicular thornscales; b, coenenchymal spindles.

FIGURE 16. T. merguiensis Gordon, 1926: a, holotype, BMNH 1933.5.3.104; b, another specimen labelled BMNH 1933.5. 3.104.