Haliclona spongiosissima ( Topsent, 1908 )

Schejter, Laura, Cristobo, Javier & Ríos, Pilar, 2024, New records of demosponges (Porifera) from the South Orkney Islands (Antarctica) with a checklist for the region, Zootaxa 5403 (4), pp. 401-430 : 421

Haliclona spongiosissima ( Topsent, 1908)

( Figure 11a–f )

Restricted synonymy: Chalina spongiosissima Topsent, 1908 .

Material examined: 2 specimens collected at stations 16 ( SOI; 60°40,992'S, 46°14,560'W; 104 m; 7/3/2012) and 17 ( SOI; 60°42,260'S, 46°01,18'W; 86 m; 8/3/2012; MACN-In 44366) .

Description: Sponge very soft and compressible, beige in colour in living specimens, and white in the preserved state. Digitate or ramified, with multiple oscula irregularly distributed along the branches ( Figure 11a ). The sponge has a hispid surface due to the protruding fibres. The ectosome lacks spicules, it has the appearence of a dermal membrane and the screened surface is evident in the fresh but also in the preserved specimens ( Figure 11c, d ). Spicules are oxeas of 240–320 µm by 10 µm ( Figure 11b ), although smaller and thinner oxeas (probably in formation oxeas) were observed in one of the specimens (195–240 µm by 5 µm). The skeleton consists in principal fibres of about 3 spicules, joined by secondary fibres or single spicules ( Figure 11e, f ).

Remarks: This is an uncommon species, only recorded by Topsent (1908), Koltun (1964) and Desqueyroux (1975). This finding represents the first record for the SOI. The photographs here provided also represent the first ones for the species, previously known only from the illustrations in the original description.

Figures

FIGURE 11. a–f. Haliclona spongiosissima. a. general morphology, scale: 3 cm; b. oxea, scale: 55 µm, c. detail of the oscula and the screened surface in a fresh specimen, scale: 1mm, d. detail of the screened surface in a dried specimen, scale: 1mm, e–f. choanosomal skeleton, detail of the spicule’s arrangements, scale: 200 µm; g–i. H. (Gellius) rudis, g. general morphology, scale: 2 cm, h. sigma, scale: 35 µm, i. oxea, scale: 160 µm; j–p. H. (G.) cf. cucurbitiformis, j. general morphology, scale: 3 cm, k. oxea, scale: 100 µm, l. sigmas, scale: 30 µm, m. macroscopic view of the choanosomal skeleton, scale: 1 mm, n. macroscopic view of the surface and the ectosome, scale: 1 mm, o. microscopic view of the spicule arrangement in the choanosomal skeleton, scale: 200 µm, p. detail of the choanosomal skeleton, scale: 200 µm.