Trimuricea caledonica Grasshoff, 1999

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 : 11

Trimuricea caledonica Grasshoff, 1999

( Figs. 4 c, 7–8)

Trimuricea caledonica Grasshoff, 1999: 48 , figs. 81–83; Grasshoff & Bargibant 2001: 183; Fabricius & Alderslade 2001: 196.

Material: SMF 6752, part of holotype, New Caledonia, W lagon, Off Nouméa, Ilot Canard, Stn 136, 23 m; SMF 6753, part of paratype, New Caledonia, W GRext, Passe de Koumac, 35 m; SMF 6754, paratype, South Pacific Ocean, New Caledonia

Description (modified after Grasshoff 1999). The complete holotype was a large fan 50 cm high, with many anastomoses; only a portion is shown in Fig. 4 c. The polyps are situated all around the branches, densely crowded, leaving little free coenenchyme in between. Calyces are dome shaped and up to 0.30 mm high and 1 mm wide.

The points have 2–4 triradiates ( Fig. 7 a) and 1–2 curved, hockeystick or boot-shaped sclerites, or spindles ( Fig. 7 b), 0.10–0.20 mm long. The upper ray of the triradiates and the upper part of the spindles is smooth for up to 0.15 mm, rather wide and blunt ended. The collaret spindles are 0.20–0.30 mm long ( Fig. 7 c); the middle part is less tuberculate than both ends. These polyp sclerites have very few tubercles. A few tentacle scales are present, up to 0.09 mm long ( Fig. 7 d).

The calyces have thornscales, 0.20–0.30 mm long, with a short, smooth, blunt thorn up to 0.12 mm long ( Fig. 8 a).

The coenenchyme has spindles and crosses, 0.15–0.40 mm long, with simple tubercles ( Fig. 8 b). Some of these spindles have a side branch which maybe thorn-like. Furthermore, small, irregular shaped sclerites are present, 0.10–0.16 mm long ( Fig. 8 c).

Colour. The live colony was red (for live colony photo see Grasshoff & Bargibant 2001). When dry it is dark brown, but it is yellowish-grey when preserved in fluid. No information about the colour of polyps is available.

Remarks. This species differs from all other Trimuricea species by having small, irregular shaped sclerites in the coenenchyme ( Fig. 8 c), which were not reported by Grasshoff. Noteworthy, we noticed irregular radiates, and derivatives of radiates, similar to those in Fig. 8 c, that occur in the basal parts of colonies, and in branches with relatively solid axis, in other Trimuricea species. Therefore, we do not exclude the possibility that the piece of the colony we received from SMF might have been cut from the basal parts or older side branches of the colony, not from the top of the colony. This might also explains why Grasshoff did not mention these types of sclerites in the original description of T. caledonica . On the other hand it is possible that these small sclerites were missed by Grasshoff’s technician making the drawings.

If we assume that the irregular radiates ( Fig. 8 c) are not from the top of the colony, then T. caledonica mostly resembles T. inermis , and T. omanensis n. sp., however, it differs in having many thornscales and triradiates in the polyp with very smooth, blunt, thorn and upper ray. In addition, these thornscales are slightly larger and have wider and more tuberculate base than those in T. omanensis n. sp. and T. inermis .

The specimens described by Grasshoff were later broken in parts and stored in both MNHN and SMF. There is an additional fragment of paratype stored in SMF (SMF 6754), which is not mentioned by Grasshoff (1999: 48), and it could be a fragment of SMF 6753. Grasshoff did not mention the number of spindles in the collaret.

Figures

FIGURE 4. Holotype colonies: a, T. africana, Gordon, 1926, BMNH 1933.5.3.102; b, T. bicolor n. sp., RMNH Coel. 39860; c, T. caledonica SMF 6752; d, T. flava n. sp., RMNH Coel. 39861.

FIGURE 7. The polyp sclerites of T. caledonica Grasshoff, 1999, paratype, SMF 6753: a, point triradiates; b, point spindles; c, collaret spindles; d, tentacle scale.

FIGURE 8. Sclerites of T. caledonica Grasshoff, 1999, paratype, SMF 6753: a, calicular thornscales; b, coenenchymal spindles; c, small, irregular shaped coenenchymal sclerites. Scale at ‘ c’, only applies to ‘ c’.