Cinachyra antarctica Carter 1872

Cinachyra antarctica (Carter, 1872)

(Fig. 2)

Cinachyra antarctica (Carter, 1872): Burton 1929: 419, 1932: 264, 1938: 5. Koltun 1976: 167. Desqueyroux 1975: 55, pl. 1, figs. 10–12. Desqueyroux-Faúndez 1989: 104, pl. 1, figs. 3a–c, pl. 6, figs. 33–34. Barthel et al. 1990: 122, 1997: 47. Gutt and Koltun 1995: 230. Campos et al. 2007a: 688–690, figs. 2–11, tab. 1.

Synonymy:

Tethya antarctica Carter, 1872: 412, pl. 20, figs. 1–10.

Cinachyra vertex Lendenfeld, 1907: 310 –322, pl. 21, figs. 17–24, pl. 22, figs. 1–42, pl. 23, figs. 1–19. Cinachyra vertex monticularis Kirkpatrick, 1908: 11, pl. 10, figs, 15, 16, pl. 11, figs. 1–3.

Material. 7 specimens from station 048-1 (SMF 11795, 11764), 602.1 m, 70° 23.94' S, 8° 19.14' W, 12.01.2008. Material examined for comparison: BMNH 1928.11.15.201, “Discovery” Investigations, 1928, Stn. 42, South Georgia, 120–204 m, wet specimen.

Description. All specimens very small juvenile sponges of about 5 mm x 4 mm. A large osculum surrounded by a very dense regular fringe of spicules at the top (Fig. 2). At the basis, few rooting spicules present. Surfaces with very small conules bearing short, protruding bundles of spicules. Skeleton of radially arranged bundles of triaenes and oxeas, originating from the center and diverging towards the exterior, often breaking trough the epidermis, thus forming the fringe at the osculum, spicule bundles at the surface and root tufts. Within the choanosome, free oxeas present. Sigmaspires very abundant, freely within the entire tissue. Epidermis composed of a very dense layer of spongin with grains of sand incorporated (Fig. 2). Spicule sizes in all specimens very variable, with anatriaenes and protriaenes up to 2000 µm and oxeas about 600 to 1100 µm, sigmaspires 20 µm.

Remarks. Spicules of this species have been well investigated and documented by Campos et al. (2007a) and Lendenfeld (1907). The spicules of our new specimens fit very well within the known schemes. The type material of C. antarctica, described by Carter (1872), is about 5 to 10 cm large, bears very long, protruding spicule bundles, and has no distinct spicular fringe around the osculum. Also, the holotype has no sigmaspires. By these characters our specimens therefore differ from the typical C. antarctica. Lendenfeld (1907) made a remarkable description of a new species he called Cinachyra vertex. The large specimens of this species differ from the C. antarctica holotype only in the possession of sigmaspires. The species therefore was synomymized with C. antarctica by Burton (1929), who considered the missing sigmaspires in the holotype to be a simple individual feature of the specimen. This synonymy was maintained by Campos et al. (2007a). Still, what makes the description by Lendenfeld (1907) so remarkable is the fact that he was able to examine not only adults, but also juvenile sponges. Thus he could document the development of C. antarctica in detail, with many specimens representing different growth stages. The clear line of development between these specimens makes their identity as representatives of a single species clear, even though the youngest differ strongly from the adults. The youngest sponges portrayed by Lendenfeld (1907) show exactly the same characteristics as our new SYSTCO-specimens: The dense fringe around the osculum, developing root system, very small, almost absent spicule bundles, and the epidermis with strong incorporation of sand in one layer (called “Sandpanzer” by Lendenfeld 1907).