Halichondria (Halichondria)

Morozov, Grigori, Sabirov, Rushan & Zimina, Olga, 2019, Sponge fauna of the New Siberian Shoal: biodiversity and some features of formation, Journal of Natural History 52 (47), pp. 2961-2992 : 2961-2992

Halichondria (Halichondria) sp.

( Figure 11 (a))

Description

Body elongated, cylindrical, with peduncle. Consistency is fragile and crumbly. The surface is uneven, scabrous, and coarse-pored. Dermal membrane is a thin crust filled with a layer of disorderly scattered spicules lying tangentially; easily separated from the tissues below. The largest of the fragments examined was about 2 cm in height and 1 cm in diameter. Colour (in alcohol) is light grey.

Skeleton

The main skeleton consists of quite compact, more or less longitudinally arranged, branching bundles, which have a thickness of 3 – 6 spicules. Numerous disorderly scattered single spicules fill the spaces between the main bundles. Towards the surface the bundles of the main skeleton become oriented more or less perpendicular to the ectosome, supporting the superficial crust.

Spicules

( Figure 11 (a)) Slightly curved, rather long-pointed oxea, dimensions: 243.7 – 443 – 604.2 (n = 30) × 8.5 – 15 – 18.5 (n = 25) µm.

Distribution

East Greenland Shelf, north-west of the Faroe Islands, the Barents and Kara seas, north of the New Siberian Islands (st. A-57). Depth range: 18 – 494 m.

Remarks

This species is quite similar to H. oblonga ( Hansen 1885) except for the skeletal structure. As Lundbeck noted (1902, p. 24 – 26), the main skeleton of H. oblonga consists of an irregular network of loose fibres, in which the ‘ spread spicules outside the fibres as good as none are found ’. Furthermore, examined specimens are characterised by the absence of special ectosomal skeleton. To assess these differences, additional specimens need to be examined.

Figures

Figure 11. Halichondria sp., scanning electron microscope (SEM) images of oxea.