Leucetta pyriformis Dendy, 1913

Figs 47a–c, 48a–e

Leucetta pyriformis Dendy, 1913: 11, pl. 1 fig. 7, pl. 4 fig. 3.

? Leucetta microraphis; Voigt et al. 2017: 21, figs 12a–d (cf. below).

Material examined. RMNH Por. 9528, Saudi Arabia, Jeddah, near Thuwal, Shi'b Nazer (exposed), 22.303417°N 39.048917°E, depth 6 m, scuba, coll. N.J. de Voogd. field nr. THU02/JED011, 6 November 2014;? ZMA Por. 10461, Seychelles, Mahé, NE coast, North East Point, 4.5833°S 55.4667°E, depth 0–5 m, snorkeling, coll. R.W.M. van Soest, field nr. NIOP-E stat. 604, 8 December 1992.

Description. In situ these are globular to lobate, white-transparant sponges (Figs 47a–b), with at the surface giant triactines clearly visible to the naked eye. There is a narrow atrial cavity in the center of the lobes, ending in an oscule with small rim. Largest individual lobe 3 cm high, 2 cm in diameter. Preserved fragments (Fig. 47c) are yellowish white in color and rough looking and feeling. Consistency firm to hard.

Aquiferous system. Leuconoid.

Skeleton. Dense mass of triactines, with giant triactines especially numerous at the surface, and with tetractines at the atrial surface.

Spicules. Giant triactines, small triactines, and tetractines. The Saudi Arabian material is slightly different from the Seychelles material and both differ slightly from Dendy’s type specimens from Cargados Carajos, so we provide spicule data for all specimens separately.

RMNH Por. 9528: Giant triactines (Fig. 48a), equiradiate, equiangular, 504– 1073 –1711 x 61 – 131.8 –204 µm; ZMA Por. 10461: 354– 852 –1470 x 42 – 109.8 –181 µm; Dendy (1913): 1000 x 100 µm.

RMNH Por. 9528: Small triactines (Figs 48b), equiradiate, equiangular, 102– 191 –234 x 11 – 14.9 –24 µm, some smaller sagittal triactines (Fig. 48c) with wavy paired actines may represent spicules from the oscular rim; ZMA Por. 10461: 132– 182 –222 x 11 – 14.8 –19 µm; Dendy (1913): 170 x 12.5 µm, including some sagittal triactines.

RMNH Por. 9528: Tetractines, (Fig. 48d) basal radiate system similar to triactines, but actines smaller and thinner, 121– 152 –184 x 8 – 11.7 –14 µm; apical actines (Fig. 48e) relatively long, straight, sharply pointed, 47– 99 –146 x 3 – 8.1 –11 µm; ZMA Por. 10461, respectively 133–161–201 x 9 – 12.9 –17 µm and 41–118–164 x 5 – 9.2 –11 µm; Dendy (1913): similar in size to triactines, apical actine long and slender.

Distribution and ecology. Saudi Arabia, Seychelles, Cargados Carajos, on reefs at shallow depth. Burton (1959) reported this species from the Maldives, but provided no description.

Remarks. Dendy’s (1913) type material is similar in shape (although slightly smaller) and also has the giant triactines clearly visible at the surface (cf. Dendy 1913: pl.1 fig. 7). The white live color was not recorded by Dendy. The combination of characters differs clearly from Leucetta chagosensis (yellow, smooth, with clearly thinner giant triactines, and the apical actines of the tetractines usually curved) and L. microraphis (red-browngreenish, apical actines of the tetractines thin and usually curved).

Voigt et al. ’s (2017) record of L. microraphis consisted of pinkish white lobes, with prominent oscules. The transparent surface shows giant triactines like in our material, and the apical actines of the tetractines are long, up to 180 x 13 µm, so we assume that their record could belong to the present species.

Unfortunately we were not succesfull in obtaining partial 28S sequences.