Clytia gigantea ( Hincks, 1866 )

Calder, Dale R., 2012, On a collection of hydroids (Cnidaria, Hydrozoa, Hydroidolina) from the west coast of Sweden, with a checklist of species from the region 3171, Zootaxa 3171 (1), pp. 1-77 : 46-47

Clytia gigantea ( Hincks, 1866)

Figs. 46 , 47

Campanularia gigantea Hincks, 1866: 297 .— Jäderholm, 1909: 69, pl. 7, figs. 1–3.

FIGURE 47. Clytia gigantea : gonotheca, ROMIZ B3917. Scale equals 0.5 mm.

Type locality. UK: Scotland, Lamlash Bay ( Hincks 1866: 297) .

Museum material. Kosterhavet, 58°53.093’N, 11°05.668’E, 20–30 m, 09.ix.2010, biological dredge, R / V Nereus , on tube of polychaete, one colony, up to 2.2 cm high, with gonothecae, ROMIZ B3917 .

Remarks. This nominal species has sometimes been combined with Clytia hemisphaerica ( Linnaeus, 1767) . Cornelius (1982) considered them identical, and a number of recent authors, including me ( Calder, 1991; Cairns et al. 2002), adopted that opinion. After examining the material above, however, Clytia gigantea ( Hincks, 1866) is upheld as a valid species based on a combination of characters including its strikingly robust colony form, sparingly branched pedicels, and exceptionally large, elongate, gradually tapered hydrothecae. Moreover, hydrothecal cusps in C. gigantea are linguiform ( Fig. 46 ) rather than wavy as in C. hemisphaerica . Specimens studied here were much like those reported earlier from Bohuslän by Jaderholm (1909: pl. 7, figs. 1–3). In reporting the species from the Oslofjord, Norway, Christiansen (1972) noted that some hydrothecae in his material reached 3 mm long. Ones exceeding 2 mm in length were observed on the hydroid colony reported herein from Kosterhavet.

Reports of Clytia gigantea from the Mediterranean, and from the Atlantic and Pacific coasts of North America (see below), need confirmation. The species, or a variant of it, has also been reported from Chile ( Leloup 1974; Galea et al. 2009).

Gonophores of this species, examined here (Fig. 47), are previously unknown in Europe. Those of the variant form from Chile have been described and illustrated by Leloup (1974) and Galea et al. (2009).

Reported distribution. West coast of Sweden.—Bohuslän ( Jäderholm 1909, as Campanularia gigantea ).

Elsewhere.—Boreal waters of the North Atlantic from Norway to Great Britain in Europe ( Hincks 1868; Christiansen 1972), and from Newfoundland to Cape Cod in North America ( Fraser 1944); questionable records exist from the Mediterranean (e.g., Pieper 1884; Babić 1904), the Queen Charlotte Islands in the northeast Pacific ( Fraser 1937, as Campanularia gigantea ), and Chile ( Leloup 1974; Galea et al. 2009).

Figures

FIGURE 46. Clytia gigantea: two hydrothecae, ROMIZ B3917. Scale equals 0.5 mm.