Parascyphus repens

Parascyphus repens (Jäderholm, 1904)

(fig. 18A–D, table 30)

Thyroscyphus repens Jäderholm, 1904b: 8; 1905: 19, pl. 7 figs 8–10.

Parascyphus repens: Vervoort, 1972a: 95, fig. 28; Leloup, 1974: 25, fig. 20; Stepanjants, 1979: 61, pl. 10 fig. 3A–B; El Beshbeeshy, 1991: 137, fig. 32.

Material examined. Stn. CCO — 09.iii. 2006, 18 m, S144 (18 m): several sterile colonies, up to 7 mm high, epizoic on Symplectoscyphus sp.; S140 (0–20 m): one fertile colony, about 1 cm high, on algae and sponge (MHNG INVE 53433). Stn. CPA — 09.iii. 2005, 15 m, S170: small colonies, less than 1 cm high, epizoic on Symplectoscyphus subdichotomus.

Type locality. North Beagle Canal, south of Slogget Bay, Tierra del Fuego.

Description. Colonies small (up to 1 cm high, rarely more), branched or unbranched, arising from a creeping stolon. Cauli monosiphonic, divided into successive internodes by means of transverse to slightly oblique nodes, not always distinctly marked. Internode ringed or wrinkled proximally; with distal apophysis supporting hydrotheca; apophyses alternately directed left and right. Branching of caulus occasional. Hydrothecae borne directly on stem apophyses or on several successive, short segments. Hydrotheca tubular, tapering basally, with almost straight abcauline wall and basally-swollen adcauline wall; margin with four triangular, pointed cusps; ad- and abcauline cusps smaller than laterals; closing apparatus composed of four triangular plates firmly attached to hydrothecal rim. Gonothecae borne on stem apophyses by means of short, ringed pedicels; large, ovoid, gradually narrowing towards base, apex provided with large, rounded aperture. Gonothecal contents badly preserved.

Remarks. The number of segments which make the junction between stem apophyses and hydrothecae is quite variable. Vervoort (1972a), in his material from the Strait of Magellan and the Atlantic coast of South America, observed 1–3 such segments, while Leloup (1974) found up to 7 in his Chilean specimens. In present material, the hydrothecae are borne either directly on their corresponding stem apophyses (sample S144) or on up to 5 short, quadrangular segments (sample S140).

Hydroid epibionts. Modeeria rotunda (Quoy & Gaimard, 1827).

World distribution. Santa Cruz (Argentina), Strait of Magellan, and Atlantic coast between Tierra del Fuego and Falkland Islands (Vervoort 1972a), Crozet (Stepanjants 1979).

Records from Chile. This species was previously recorded from both Canals Beagle and Chacao, Seno Reloncaví and Golfo de Ancud (Leloup 1974). The present material originates from both Canals Copihue and Pasaje.