Mycale (Oxymycale) acerata Kirkpatrick 1907

Mycale (Oxymycale) acerata Kirkpatrick, 1907

(Fig. 10 C)

Mycale acerata Kirkpatrick, 1907: 280 –282, 1908: 36, pl. 20, fig. 1, pl. 24, fig. 10. Burton 1929: 430, 1934: 23, pl. 8, figs. 1–4. Koltun 1964: 33, pl. 5, figs. 1–7, 1976: 169. Boury-Esnault & Van Beveren 1982: 52–53, figs. 14f–i. Ríos et al. 2004: 110– 111, fig. 9.

Synonymy:

Mycale acerata var. minor Hentschel, 1914: 63 –64. Mycale acerata var. sphaerulosa Hentschel, 1914: 63.

Material. 11 fragmentary specimens from station 048-1 (SMF 11800, 11848 grown together with a specimen of Myxilla asigmata, 11849, 11850, 11859–11865), the true number of specimens sampled cannot be reconstructed from the fragments; 602.1 m, 70° 23.94' S, 8° 19.14' W, 12.01.2008. Material examined for comparison: BMNH 1908.2.5.170, holotype, National Antarctic Expedition HMS “Discovery”, W.Q. 25.IX.03, 12 hole (243), described in Kirkpatrick (1908), wet specimen.

Description. Massive, soft sponges, whitish in ethanol. Skeleton a plumose reticulation of anastomosing spicular-spongin fibres fanning out towards the surface. Basal fibres very thick, in older parts of the sponge body often the only remains after tissue has decayed. Thus the sponges show a very characteristic habit as a mixture of living and dead parts. Surface covered by a distinct reticular ectosome. Oxeas 550 to 950 µm long, palmate anisochelae 80 to 100 µm long.

Remarks. This well-known and wide-spread species has been described and illustrated in detail by Kirkpatrick (1908), Koltun (1964) and Ríos et al. (2004). Our new specimens are in accordance with earlier descriptions. The typical growth form has been pictured by Kirkpatrick (1908) and Ríos (2006), and is even recognizable on underwater-photographs taken by ROV. Representatives of this species are the largest and also among the most abundant sponges sampled on SYSTCO I station 048-1, although the total number of specimens cannot be evaluated due to the fragmentary state of most specimens. As these sponges are both large and abundant, they very likely provide a great range of habitats for associated fauna. This will be examined in a separate study conducted on our new material. As a constraint to this point though, we have to state that the species has proven to be toxic at least for goldfish (McClintock, 1987).