Cladiella thomsoni (Tixier-Durivault, 1944)

Lazar, Einav, Mcfadden, Catherine S., Huchon, Dorothée & Benayahu, Yehuda, 2025, Redescription of type material of the genus Cladiella Gray, 1869 (Octocorallia, Malacalcyonacea, Cladiellidae) from the Red Sea, Zootaxa 5674 (1), pp. 1-84 : 73-76

Cladiella thomsoni (Tixier-Durivault, 1944)

( Figs. 54B , 57 & 58 )

Lobularia Thomsoni Tixier-Durivault, 1944b: 345 ; Tixier-Durivault 1948: 148–153, Figs. 141–147.

Material examined. Syntypes. MNHN-IK-2000-392, Red Sea, 1850, coll. A. B. Clot Bey; MNHN-IK-2000-399 and MNHN-IK-2000-403 same details as MNHN-IK-2000-392 .

Description. Syntype MNHN-IK-2000-399 is an encrusting colony measuring with a maximum cross-section of 61 x 60 mm ( Fig. 54B ). Its small rounded laterally flattened knob-like lobes are densely packed and arranged in groups separated by empty spaces. The retracted polyps appear as small pits on the lobe surface.

The sclerome of the polyps comprises platelets, 0.05–0.07 mm long, mostly featuring a lateral median constriction ( Fig. 57A ). Their surface mostly presents a cristate-like texture. Some of these platelets are figure-eights and feature an elevated circumferential rim, thus presenting a central depression that can be divided in two pits. The surface of the lobes comprises poorly developed dumbbells, 0.08–0.10 mm long, featuring mostly rounded tubercles ( Fig. 57B ). The dumbbells from the interior of the lobes are 0.08–0.11 mm long with rounded or blunt-ended conical tubercles, separated by a bare waist 0.02–0.03 mm wide and 0.02–0.03 mm long ( Fig. 57C ). The sclerites of the surface of the base comprise poorly developed dumbbells, 0.05–0.07 mm long, ornamented with pointed conical tubercles ( Fig. 58A ). The dumbbells from the interior of the colony base are 0.08–0.11 mm long, featuring sparsely placed wide pointed conical tubercles with a bare waist, 0.02–0.04 mm wide and 0.01–0.03 mm long ( Fig. 58B ).

Color. The dry Syntype MNHN-IK-2000-399 is light brown.

Remarks. The initial species assignment of L. thomsoni ( Tixier-Durivault 1944b: 345) did not depict the morphological characters of the syntype colony. They were subsequently presented in the revision of the genus ( Tixier-Durivault 1948: 148–153, Figs. 141–147). This species is characterized by its rounded tubercles on the poorly developed dumbbells of the surface layer of the lobes and its pointed conical tubercles on the dumbbells from the interior of the colony base.

The current examination of the colony morphology and sclerites of syntype MNHN-IK-2000-392 corresponds to its description by Tixier-Durivault (1948). Syntypes MNHN-IK-2000–399 (not shown) and MNHN-IK-2000- 403 (not shown) resemble MNHN-IK-2000-392, except for their size. No details are provided regarding the exact locality in the Red Sea where the type colony was collected .

Distribution. Red Sea.

Figures

FIGURE 54. Images of Cladiella type colonies. A. Cladiella tenuis (Tixier-Durivault, 1944), holotype, MNHN-IK-2000- 391. B. Cladiella thomsoni (Tixier-Durivault, 1944), holotype, MNHN-IK-2000-399. C. Cladiella variabilis (Tixier-Durivault, 1944), syntype MNHN-IK-2000-395.

FIGURE 57. Cladiella thomsoni (Tixier-Durivault, 1944), holotype, MNHN-IK-2000-399. Scanning electron micrographs of sclerites of the colony top. A. Polyp sclerites. B. Poorly developed dumbbells of the surface of the lobes. C. Dumbbells from the interior of the lobes.

FIGURE 58. Cladiella thomsoni Tixier-Durivault, 1944, holotype, MNHN-IK-2000-399. Scanning electron micrographs of sclerites of the colony base. A. Poorly developed dumbbells of the surface of the base. C. Dumbbells from the interior of the base.