Sphaerotylus borealis Swartschewsky, 1906

Morozov, Grigori, Sabirov, Rushan Mirzovich & Anisimova, Natalia, 2018, New data on sponges from Svalbard Archipelago with a description of a new species of Halicnemia, Journal of Natural History (J. Nat. Hist.) 52 (7 - 8), pp. 491-507 : 498-499

Sphaerotylus borealis Swartschewsky, 1906

( Figure 5 (a–g))

Proteleia borealis Swartschewsky 1906, p. 315 , pl. X fig. 1, pl. XIII fig. 2

Spaerotylus borealis: Koltun 1966, p. 83 , fig. 55, pl. XXX figs. 1–5; Plotkin 2004, p. 543, figs. 1I, 2I, 4B; Plotkin et al. 2016, pp. 14–17, figs. 10, 11

Description

( Figure 5 (a)) Sponge cushion- or disc-shaped, up to 2.5 cm in diameter and 1.5 cm in height. Surface shaggy with several cylindrical or conical papillae up to 1.2 cm in length, some with oscula (about 1 mm in diameter) on the summits. Colour light brown.

Skeleton

The choanosomal skeleton is formed by the thick radial bundles of styles and disorderly scattered small tylostyles. Ectosomal skeleton consists of two layers: (1) palisade layer of small styles and (2) underlayer of intermediary spicules arranged tangentially. Surface hispidation caused by long styles and sphaerotyles, basal ends of which anchored in the ectosome.

Spicules

( Figure 5 (b–g)) Large polytylotes styles, dimensions: 583–1351–2517 (n = 20) × 7.4–26– 38.5 µm (n = 15); styles (tylostyles) intermediate, dimensions: 191.85–459.4–707.8 (n = 30) × 10.5–12.75– 15.6 µm (n = 10); small tylostyles, of two distinct categories: straight and curved (in their apices), dimensions: 110–141.4–218.8 (n = 30) × 2.9–4.3– 6.9 µm (n = 30); long styles and sphaerotyles (with rough heads) up to 7.7 mm in length and 44 µm thickness.

Distribution

Norwegian Sea, Barents Sea (south-western part, Franz Josef Land), Spitsbergen, White and Kara (Shokalsky Strait) seas.

Figures

Figure 5. T. norvegica, (a) habitus; (b) cross section through the sponge surface; (c–e) SEM images of spicules; (c) style; (c1) details of apices of style; (d) strongylaster; (e) spheraster.