Caulophacus

Janussen, Dorte & Reiswig, Henry M., 2009, Hexactinellida (Porifera) from the ANDEEP III Expedition to the Weddell Sea, Antarctica, Zootaxa 2136, pp. 1-20 : 16-17

Caulophacus sp.

Material examined: SMF 10608, 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; SMF 10609, ANDEEP III Exped., R.V. 'Polarstern', stn PS67/142-6, Weddell Sea, Antarctica , 18 Mar. 2005, 62°09.93'S, 49°30.47'W to 62°09.80'S, 49°30.59'W, 3403–3404 m, ethanol.

Description and remarks: Two additional partial specimens, both stalks, attributable to Caulophacus , are inadequate to place more definitely. The first, from station PS67/059-10, collected along with C.

(Oxydiscus) weddelli , is a small stalk, 91 mm long, 2.7 mm diameter at its narrowest point, and 7.2 mm at its slightly inflated upper end. It is a hollow tube composed of diactins thoroughly fused by synapticula, characteristic of Caulophacus stalks. Associated with it are a few slightly pinular spiny hexactins and pentactins as surface spicules, with ray lengths of 100–250 µm. The only microscleres present are oxyhexasters along with hemioxyhexasters and oxyhexactins, 100–160 µm in diameter. Spiculation is thus similar to Bathydorus subtilis , but no specimens of that species were recovered from that station and such a fused stalk is not known from that species. The combination of stalk of fused diactins and spicules suggest this might be a new form of C. (Caulophacella) but the condition of the specimen is too poor to base a taxonomic description upon it. For now it is best designated as Caulophacus sp., but it suggests an interesting taxon is yet to be discovered in this area.

The second specimen from station PS67/142-6 consists of fragments of a larger stalk. It consists of diactins thoroughly fused by synapticula and contains a few loose spiny hexactins. It is almost certainly a Caulophacus , but cannot be attributed to any subgenus or species on the basis of its constituents.