Halopteris catharina ( Johnston, 1833 )

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 : 45

Halopteris catharina ( Johnston, 1833)

Fig. 44

Plumularia catharina Johnston, 1833: 497 , figs. 61–62.— Jäderholm, 1909: 107, pl. 12, fig. 7.

Plumularia catharinae .— Segerstedt, 1889: 21, 27 [incorrect subsequent spelling].

Halopteris catharina .— Rees & Rowe, 1969: 21.

Schizotricha catharina .— Jägerskiöld, 1971: 64.

Type locality. UK: England, Berwick ; Scotland, Firth of Forth ( Johnston 1833: 497) .

Museum material. Väderöarna, 58°35.010’N, 11°04.864’E, 121– 50 m, 13.ix.2010, biological dredge, R / V Nereus , on a bivalve, one small colony, 5 mm high, without gonophores, ROMIZ B3929 .

Remarks. Relatively recent taxonomic accounts of Halopteris catharina ( Johnston, 1833) have been given by authors including Ramil & Vervoort (1992), Cornelius (1995b), and Schuchert (1997). Most records of the species have been from boreal and temperate waters of the eastern north Atlantic, and it appears to be relatively common at moderate depths along the west coast of Sweden (see Checklist). It is also known from Danish waters ( Kramp 1935b, as Schizotricha catharina ) and from the Oslofjord ( Christiansen 1972, as Antennella catharina ). The species can be distinguished from known congeners in having hydrocladia that are usually arranged in opposite pairs, and hydrothecae that are flanked by two pairs of lateral nematothecae. Female gonothecae of H. catharina resemble a flattened cylinder ( Schuchert 1997).

Reports of H. catharina from pelagic Sargassum in the western North Atlantic were considered misidentifications of H. diaphana (Heller, 1868) earlier by me (Calder 1997). In turn, records of H. diaphana from that region have been referred to H. alternata ( Nutting, 1900) by Schuchert (1997), who indicated that H. diaphana appears limited to the Mediterranean Sea and to Brazil.

Reported distribution. West coast of Sweden.—Säcken Reef area to southern Kattegat ( Jägerskiöld 1971).

Elsewhere.—Atlantic Ocean from Trondheim, Norway, and Iceland to Namibia in the east ( Jäderholm 1909; Ramil & Vervoort 1992), and from Georgia, USA, to the Straits of Magellan in the west ( Vervoort 1972).

Figures

FIGURE 44. Halopteris catharina: part of hydrocladium with hydrothecae and nematothecae, ROMIZ B3929. Scale equals 0.5 mm.