Symplectoscyphus cumberlandicus Jaderholm 1905

Symplectoscyphus cumberlandicus (Jäderholm, 1905)

(Pl. 1S, Fig. 2 T, U)

Symplectoscyphus cumberlandicus — Peña Cantero, Svoboda & Vervoort, 2002: 1519, fig. 3. — Peña Cantero, 2010: 769, fig. 5B, C.

Material examined. Stn. SHO — 20.ii.2011, Ant.07/2011 (20–30 m): a fragmentary colony composed of two stems ca. 10 cm high, both bearing numerous gonothecae (MHNG-INVE-79783); 26.ii.2011, Ant.10/2011 (20–30 m): fragmentary colony, largest fragment ca. 10 cm high (taller in life), fertile female (MHNG-INVE-79784).

Remarks. For a description of S. cumberlandicus and its synonymy, see Peña Cantero et al. (2002) and Peña Cantero (2010). This species has a very brittle perisarc and preserved material is often fragmentary. There are only two descriptions of the general shape of the colonies in the literature (Jäderholm 1905, Peña Cantero 2010). The living specimen from sample Ant.07/2011 is illustrated on Pl. 1S. It is composed of two stems arising from a well developed rhizoidal hydrorhiza. Their branching is regular, with side branches arising generally every three hydrothecae. The stems are polysiphonic for most of their length, as well as some of the side branches. These may divide again, in the same manner as the main stem, and form additional, lower order branches (up to the 3rd order branches are present). Accessory hydrothecae often occur on the basal parts of the side branches, more rarely on the main stem. Gonothecae are abundantly borne on the 2nd and 3rd order branches; in places, they are given off from below successive hydrothecae, and partly rely on each other, so that their long axis is no longer straight, but S-shaped. Those in the present material are much longer (2600–3015 µm long) and wider (780–1000 µm), and have a greater number of transverse rings (15–20) than previously described [compare to table 3 in Peña Cantero et al. (2002)]. Their terminal tube is 210–270 µm long, 190–220 µm wide in middle, and its diameter at aperture is 255–295 µm. In sample Ant.10/2011, their content appear slightly better preserved than in sample Ant.07/2011, and their sex is likely female, possibly suggesting sexual dimorphism.

Geographical distribution. Circum-antarctic (Peña Cantero et al. 2002).