Cladiella tenuis

Cladiella tenuis (Tixier-Durivault, 1944) (Figs. 54A, 55 & 56) Lobularia tenuis Tixier-Durivault, 1944b: 345; Tixier-Durivault 1948: 25–29, Figs. 11–14. Material examined. Holotype. MNHN-IK-2000-391, 3 fragments, Red Sea, 1844, coll. M. Portier. Description. The holotype consists of three fragments of an encrusting colony with a maximum cross-section of 100 x 85 mm, 109 x 70 mm, and 79 x 48 mm respectively (Fig. 54A). Their knob-like lobes are arranged in groups with empty spaces between them. The retracted polyps appear as small pits on the lobe surface. The sclerome of the polyps comprises platelets and some rods, 0.03–0.05 mm long (Fig. 55A). Their surface has a combined tuberculate and cristate-like texture. Some of the platelets feature a central depression surrounded by an irregular rim. The sclerites of the surface of the lobes comprise poorly developed dumbbells, 0.04–0.07 mm long, mostly with rounded tubercles (Fig. 55B). The dumbbells from the interior of the lobes are 0.05–0.07 mm long, featuring blunt-ended and rounded tubercles separated by a bare waist, 0.01–0.03 mm wide and 0.01–0.02 mm long (Fig. 55C). The surface of the colony base comprises poorly developed dumbbells, 0.04–0.07 mm long, featuring rounded and blunt-ended conical tubercles (Fig. 56A). The interior of the colony base features dumbbells, 0.07–0.09 mm long, with blunt-ended conical and some rounded tubercles separated by a bare waist, 0.02–0.03 mm wide and 0.01–0.02 mm long (Fig. 56B). Color. The dry holotype is beige-brown. Remarks. The initial species assignment of L. tenuis (Tixier-Durivault 1944b: 345) did not depict the morphological characters of the syntype colony. These were subsequently presented in the revision of the genus (Tixier-Durivault 1948: 25–29, Figs. 11–14). This species is characterized by its relatively short and massively tuberculate dumbbells, up to 0.09 mm, in the interior of the colony base. None of the sclerite drawings in Tixier-Durivault (1948) depict those of the polyps. For the rest, the current findings regarding both the colony morphology and its sclerites correspond to Tixier-Durivault’s (1948) amended description. No details are provided regarding the exact locality in the Red Sea where the holotype was collected. Distribution. Red Sea.