Gonothyraea loveni ( Allman, 1859 )

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 : 48

Gonothyraea loveni ( Allman, 1859)

Fig. 49

Laomedea loveni Allman, 1859: 138 .— Jägerskiöld, 1971: 63.

Campanularia geniculata .— Lovén, 1836: 281, pl. 6, figs. 1–10, pl. 7, figs. 11–18 [not Obelia geniculata ( Linnaeus, 1758) ].

Gonothyraea loveni .— Segerstedt, 1889: 13, 25.— Lönnberg, 1898: 52; 1899b: 17; 1903: 60.— Jäderholm, 1909: 64, pl. 6, fig. 2.— Östman, 1982a: 156; 1982b: 228; 1983: 6; 1999: 19.

Type locality. UK: Scotland, Firth of Forth , Cramond Island ( Allman 1859: 137) .

Museum material. Kosterhavet, 58°52.424’N, 11°06.178’E, 35– 11 m, 06.ix.2010, biological dredge, R / V Nereus , on algae, three colony fragments, up to 9 mm high, without gonothecae, ROMIZ B3885 .

Remarks. Gonothyraea loveni ( Allman, 1859) and G. hyalina Hincks, 1866 have been regarded as distinct by some authors (e.g. Linko 1911; Broch 1918; Kramp 1935b; Hamond 1957; Christiansen 1972; Östman 1987, 1999) and as conspecific by others (e.g. Fraser 1944; Naumov 1960; Calder 1970; Cornelius 1982; Schuchert 2009). The two have been separated on differences in structure of the hydrothecal margin, with hydroids having notched cusps with vertical lines extending down from them being assigned to G. hyalina and those with slightly notched or unnotched cusps and no vertical lines to G. loveni . Athough likely conspecific, they are listed separately in the Checklist at the end of this work.The trophosome of Laomedea neglecta Alder, 1856 is similar, although hydrothecal cusps of this small species are more distinctly bimucronate.

Gonothyraea loveni is a decidedly eurytopic species. In estuaries of the American east coast, it was active at temperatures from 0–24.5° C ( Calder 1971) and at salinities between 12–33‰ (Calder 1976). In the Gulf of Finland, it was observed at salinities as low as 5‰ by Alexander Antsulevich ( Cornelius 1995b).

Isozymes and nematocysts have been investigated in Swedish populations of G. loveni by Östman (1982a, b, 1983, 1987, 1999). Other aspects of its biology are summarized by Cornelius (1982, 1995b).

Gonothyraea loveni is common in Danish waters ( Kramp 1935b, as Laomedea loveni ) and the Oslofjord, Norway ( Christiansen 1972), as well as western Sweden (e.g., Jäderholm 1909). Cornelius (1995b) noted that the name of this species honours Sven Ludvig Lovén (1809–1895), the Swedish marine zoologist who first described and illustrated its unusual medusoids ( Lovén 1836: pl. 7, as Campanularia geniculata ).

Reported distribution. West coast of Sweden.—Kosterhavet to Öresund ( Segerstedt 1889; this study).

Elsewhere.—From Svalbard and the north coast of the Russian Federation to the Mediterranean Sea and Morocco in the eastern North Atlantic ( Cornelius 1982), and from Foxe Basin in the Canadian Arctic to South Carolina on North American shores ( Calder 1970; 1990).