Caulophacus (Caulodiscus) valdiviae Schulze 1904

Caulophacus (Caulodiscus) valdiviae Schulze, 1904

Material examined: SMF 10528/10607, ANDEEP III Exped., R.V. 'Polarstern', stn PS67/059-10, Weddell Sea, Antarctica, 15 Feb. 2005, 67°30.37'S, 0°03.74'E to 67°30.27'S, 0°04.34'E, 4648 m, ethanol.

Description and remarks. Seven fragments, probably from a single sponge, were obtained at a far eastern station of the Weddell Sea along with a fragment of one other caulophacid. Included is part of the upper stalk with lower body attached, 68 mm long by 9.6 mm diameter at its mid-waist. The largest upper body part is a sheet, 63 by 64 mm in horizontal dimensions, with a maximum thickness of 6 mm. Spiculation of six of the fragments are identical, including typical dermal and atrial pinular pentactins and hexactins, hypodermal pentactins with coarse spination on the proximal areas of all rays, principal diactins, and smooth choanosomal hexactins. Microscleres consist mainly of discohexactins with very rough rays and onychohexasters with relatively long primary rays, 19.8 (15.5–29.2) µm in length, each bearing five terminal rays, 22.5 (18.8–25.5) µm in length. This feature, following the key provided in Janussen et al. (2004:1870) allows unambiguous assignment of these fragments to C. (Caulodiscus) valdiviae, a species known from Antarctic waters off Enderby Land (Schulze, 1904) and possibly from Bellingshausen Sea (Barthel & Tendal, 1994). The seventh fragment has all of the spicules common to the other six, with addition of numerous oxyhexasters, unknown in this species. It is concluded that these are foreign intrusions from other specimens collected in the same trawl and that this fragment belongs to the same species and probably the same original specimen as the other six fragments. This report is the first record of occurrence of C. (Caulodiscus) valdiviae in the Weddell Sea region.