Chondrocladia (Chondrocladia) antarctica Hentschel 1914

Chondrocladia (Chondrocladia) antarctica Hentschel, 1914

(Fig. 13, Tab. 9)

Chondrocladia antarctica Hentschel, 1914: 77, pl. 4, fig. 6, pl. 6, fig. 5. Koltun 1964: 38.

Material. 1 specimen from station 017-10 (SMF 11752), 2189.7 m, 70° 4.58' S, 3° 19.66' W, 22.12.2007.

Description. Observed specimen (Fig. 13 A) with rounded body with thick stalk on underside and filaments on top side. Total height about 7 cm, with main part about 2.5 cm in diameter, stalk broken off at lower end, about 3 cm in length. Filaments about 1 cm in length, rarely longer. Surface hispid, consistency varying, but mainly very firm. Color alive and in alcohol greyish brown.

Skeleton (Fig. 13 B, C): Cored by a very dense aggregation of spicules originating from the rooting stalk and running into the head, there branching into several spicular tracts which form the skeletal basis of filaments. Surrounding the dense core of the sponge a thick bark-like tissue, which is cored by paratangentially arranged styles and penetrated by the tracts running into filaments. A cavity between cortex and coring spicule tracts present. Epidermis showing an accumulation of chelae which sometimes protrude above surface.

Spiculation (Tab. 9): Main spicules simple styles (Fig. 13 D–G), 925–2875 x 20–63 µm large. Among these a differentiation into two size categories present, one size class about 1400 µm in mean length and one about 2400 µm in mean length. Transitions between size classes present aggravating a final separation of size categories. Microscleres are: 1. anchorate isochelae I (Fig. 13 H), with three alae on each end, 80–109 µm in length. 2. anchorate isochelae II (Fig. 13 I), same shape as isochelae I, but distinctly smaller, 42–49 µm long. 3. c-shaped sigmas (Fig. 13 J), often relatively strong, sinuous, 89–142.5 x 44 –75 µm in size.

Remarks. The species seems to be rather rare, the only detailed reports to our knowledge are the type description (Hentschel 1914) and a record by Koltun (1964), who mainly summarizes the data of Hentschel (1914). Two further specimens were collected in the abyssal Weddell Sea during the ANDEEP II expedition (Janussen, unpubl.). One major difference exists between our sponge and the holotype: Hentschel (1914) reports a distinct difference between two size categories of styles (compare Tab. 9). However, as he mentions a distinct transition between the two size categories, his presented data might be a falsifying simplification of the true situation.