Symplectoscyphus magellanicus ( Marktanner-Turneretscher, 1890 )

Galea, Horia R., 2007, Hydroids and hydromedusae (Cnidaria: Hydrozoa) from the fjords region of southern Chile, Zootaxa 1597 (1), pp. 1-116 : 69-71

Symplectoscyphus magellanicus ( Marktanner-Turneretscher, 1890)

(fig. 16J–L, table 27)

Calyptothuiaria magellanica Marktanner-Turneretscher, 1890: 244 , pl. 5 fig. 7.

Symplectoscyphus magellanicus: Vervoort, 1972a: 158 , figs 51A–C, 52, 53.

Sertularella magellanica: Hartlaub, 1905: 637 , fig. C 4; Stepanjants, 1979: 82, pl. 14 fig. 3A–B.

Sertularella affinis Hartlaub, 1900: 43 , fig. 5; 1905: 632, figs X 3, Y 3.

Material examined. Stn. CPI — 07.iii. 2006, 18 m, S133: one sterile colony, 6.5 cm high, on sponge ( MHNG INVE 53410 ) .

Type locality. Strait of Magellan (no exact locality) .

Description. One erect colony, 6.5 cm high; slightly polysiphonic basally, becoming monosiphonic

toward middle part; stem not ramified. Colony pinnate, with main stem bearing regularly alternating side branches of same diameter and structure; stem axis slightly geniculate; side branches arising every three or more stem hydrothecae. Stem and branches divided into internodes by oblique, more or less deep, constrictions of perisarc; length of internodes varying considerably, in some parts of colony being short, long in others. Branches arising laterally below stem hydrothecae via short apophysis; a constriction of perisarc present between the apophysis and proximal end of branch. Side branches simple, rarely ramified, bearing up to 32 hydrothecae. Hydrothecae situated on distal part of internodes; biseriate, alternate and coplanar; tubular, with ad- and abcauline walls nearly parallel or slightly converging distally. Dimensions of hydrotheca extremely variable within same stem or branch. Free adcauline part as long as its corresponding adnate part or longer; wall straight or slightly convex; sometimes, surface with some indistinct undulations. Abcauline side convex, with inflexion point at middle, to nearly straight in some hydrothecae. Perisarc of abcauline wall thicker than on adcauline side. Rim slightly everted, especially on adcauline side; with no or rare, closely-spaced renovations; with three triangular cusps with pointed tips delimiting three relatively deep, rounded embayments. Closing apparatus composed of three triangular flaps, meeting centrally to form a low, pointed roof. Hydranths badly preserved, impossible to ascertain number of tentacles. Periderm yellowish. Gonothecae not found.

Remarks. The present material agrees well with Vervoort’s (1972a) redescription of this species. However, the colonies from Vema were exclusively monosiphonic, while the present material from Chile is slightly polyphonic basally. Vervoort (1972a) described some colonies having all the side branches on one side of stem.

Vervoort (1972a) synonymized Sertularella affinis Hartlaub, 1900 with S. magellanicus and this opinion is followed here.

The gonothecae of S. magellanicus still remain to be discovered.

Hydroid epibionts. Filellum serratum ( Clarke, 1879) .

World distribution. Strait of Magellan, Tierra del Fuego, Falkland Islands, Argentina ( Vervoort 1972a).

Records from Chile. The present material was collected from Canal Pitt Chico.