Polymastia invaginata Kirkpatrick, 1907

Göcke, Christian & Janussen, Dorte, 2013, Demospongiae of ANT XXIV / 2 (SYSTCO I) Expedition — Antarctic Eastern Weddell Sea, Zootaxa 3692 (1), pp. 28-101 : 40

Polymastia invaginata Kirkpatrick, 1907

( Fig. 3 B)

Polymastia invaginata Kirkpatrick 1907: 271, 1908: 15 –16, pl. 12, fig. 1b, pl. 14 figs. 5–15a. Burton 1929: 446, 1932: 338. Koltun 1964: 26, pl. 4 figs. 10–14, 1976: 168. Boury-Esnault & van Beveren 1982: 36–37, pl. 4 (13–14), figs. 9d, e, f. Plotkin & Janussen 2008: 102–109, figs. 4–5, tab. 2, 3.

Synonymy:

Polymastia invaginata var. gaussi Hentschel 1914: 49 , pl. 4, fig. 4.

Material. 1 specimen from station 017-11 (SMF 11765), 2090.7 m, 70° 4.66' S, 3° 21.37' W, 22.12.2007; 4 specimens from station 039-16 (SMF 11766–11768), 2151.3 m, 64° 28.79' S, 2° 52.74' E, 04.01.2008; 2 specimens from station 039-17 (SMF 11777) 2153.1 m, 64° 28.66' S, 2° 53.14' E, 04.01.2008; 5 specimens from station 048-1 (SMF 11782, 11791, 11792), 602.1 m, 70° 23.94' S, 8° 19.14' W, 12.01.2008.

Description. Encrusting sponges of round shape. Commonly with one or few oscula, often invaginated, with long papillae. Choanosomal skeleton made up of radial tracts of (tylo-)styles and occasionally strongyles of up to 2240 µm running straight towards the cortex, this composed of a palisade-like monolayer of tylostyles about 140 µm in length.

Remarks. Polymastiidae of ANDEEP expeditions including P. invaginata were studied in detail by Plotkin and Janussen (2008). Our new specimens, which were sampled in the same geographic region, show the same or similar characters.

An interesting point about P. i n v a g i n a t a is its remarkably wide geographical and bathymetrical distribution. During SYSTCO I expedition, specimens have been sampled between 602 and 2153 m. The shallowest record of P. invaginata was at 18 m depth (Kirkpatrick 1908), the deepest at 4800 m depth (Plotkin & Janussen 2008). The species occurs widespread in almost all Antarctic and adjacent areas (Plotkin & Janussen 2008). The rich occurrence of the species on Maud Rise (stations 039-16 and 039-17) is interesting in that it co-occurs there with Tentorium semisuberites (Schmidt, 1870) , the most abundant sponge taxon along with total absence of hexactinellids. The peculiarities of the Maud Rise fauna are discussed in Brandt et al. (2011).

Figures

FIGURE 3. Habitus pictures. A: Tetilla leptoderma Sollas, 1886 (SMF 11760), alive, ex situ, B: Polymastia invaginata Kirkpatrick, 1907 (SMF 11777), alive, ex situ, C: Tentorium semisuberites (Schmidt, 1870) (SMF 11788), alive, ex situ, D: Tentorium papillatum (Kirkpatrick, 1908) (SMF 11787), alive, ex situ, E: Stylocordyla cf. chupachups Uriz, Gili, Orejas & Perez-Porro, 2011 (SMF 11771), in ethanol, F: Iophon unicorne Topsent, 1907 (SMF 11812), in ethanol, G: Raspailia (Hymeraphiopsis) irregularis Hentschel, 1914 (SMF 11806), in ethanol, H: Inflatella belli (Kirkpatrick, 1907) (SMF 11811), in ethanol, I: Lissodendoryx (Ectyodoryx) ramilobosa (Topsent, 1916) (SMF 11808), in ethanol, J: Lissodendoryx (Lissodendoryx) cf. styloderma Hentschel, 1914 (SMF 11826), in ethanol, K: Crella (Pytheas) crassa (Hentschel, 1914) (SMF 11832), in ethanol. Scale bars: A: 30 mm, B: 10, F – K mm, C – E: 5 mm.