Haliclona (Rhizoniera) dancoi (Topsent, 1901)

Göcke, Christian & Janussen, Dorte, 2013, Demospongiae of ANT XXIV / 2 (SYSTCO I) Expedition — Antarctic Eastern Weddell Sea, Zootaxa 3692 (1), pp. 28-101 : 89-91

Haliclona (Rhizoniera) dancoi (Topsent, 1901)

( Fig. 23 , Tab. 19 )

Haliclona dancoi (Topsent, 1901) : Burton 1934: 6. Koltun 1964: 97, pl. 15, figs. 5, 6, 1976: 196.

Synonymy:

Chalina dancoi (Topsent, 1901) : Burton 1929: 420.

Reniera dancoi Topsent, 1901: 12 , pl. 2, fig. 1, pl. 3, fig. 3. Kirkpatrick 1908: 53, pl. 18, fig. 3. Hentschel 1914: 134.

Material. Several fragments of probably 2 different specimens from station 048-1 (SMF 11802, 11842), 602.1 m, 70° 23.94' S, 8° 19.14' W, 12.01.2008.

Description. Specimens ( Fig. 23 A) fragmentary. Some of whitish-beige color in ethanol (SMF 11802), others of darker, brownish color (SMF 11842), possibly representing two different specimens. Shape of living sponges unkwon. Fragments lamellar, about 5 mm in thickness. Surface hispid from protruding spicule tufts. In topview, triangular honeycomb structures between spicule tufts visible. Surface bearing several pores, larger ones probably oscules, about 2 to 4 mm in width, quite regularly arranged at distances of about 5 to 10 mm. Between these, smaller pores of about 0.5 to 1 mm diameter. Texture soft and fragile.

Skeleton: Skeleton a rather regular anisotropic reticulation ( Fig. 23 B). Primary tracts built of about 4 oxeas in thickness, running from the sponges base towards surface, which they penetrate, forming short spicule tufts. Primary tracts interconnected by oxea, which mainly occur single or pairwise, only rarely forming longer, more consistent tracts. Ectosomal skeleton absent. In some parts of sponge, high amounts of sand grains present.

Spiculation ( Tab. 19 ): Spicules almost straight, slender oxeas (fig. 23 C–E) of 610 to 820 x 15 to 29 µm. Microscleres absent.

Remarks. This species is characterized by rather few, weak characters. Still, the identification seems unquestionable. Topsent (1901) reported oxeas of 615–630 x 18–20 µm, which are in a similar range to the ones reported here. Topsent's (1901) specimens also showed similar characters in skeleton and structure of the surface. Most of his specimens, due to the sponge’s soft texture and fragility, were fragments, like ours. For some specimens, he reported a cylindrical growth. Those specimens are remarkably smaller than the ones we sampled.

The SYSTCO-specimens therefore might be larger adult representatives of the species, although the exact shape of these sponges, as stated above, cannot be reconstructed. The specimens of Topsent (1901) showed significantly fewer oscules than ours, which were smaller (1 mm) and not regularly distributed. Still, this might as well be caused by the small growth of his sponges. Koltun (1964) reported tubular specimens with an inner cavity, thus differing from the massive types of Topsent (1901). Those hollow sponges therefore show some distinct similarity to our fragmentary specimens. Koltun (1964) did not give the sizes of his sponges, but like our new ones, might have been larger adult counterparts of the small, probably juvenile specimens of Topsent (1901). Interestingly, Koltun’s (1964) specimens had oxeas with a minimum size of 343 µm, therefore being much smaller than the usual ones and especially the larger oxeas of our new specimens.

Figures

FIGURE 23. Haliclona (Rhizoniera) dancoi (Topsent, 1901), SMF 11802. A, habit alive ex situ. B, section. C – E, oxea with details. Scale bars: A: 20 mm, B: 10 mm, C – D: 100 µm, E: 30 µm.