Halecium beanii ( Johnston, 1838 )

Gil, Marta, Ramil, Fran & Agís, José Ansín, 2020, Hydroids (Cnidaria, Hydrozoa) from Mauritanian Coral Mounds, Zootaxa 4878 (3), pp. 412-466 : 427

Halecium beanii ( Johnston, 1838)

Halecium beanii: Millard, 1975: 144-145 , figs 47A-E; Cornelius, 1995a: 276–278, fig. 62; Ramil et al., 1998: 7; Medel & Vervoort, 2000: 8–12, fig. 1; Schuchert, 2005: 615–618 , fig. 5, 6.

Material examined. MSM 16 /3, stn GeoB 14796–1, ROV, 20°14.840’– 20°14.575’N, 17°40.193’– 17°40.071’W, 487–642 m, 3-XI-2010: three colonies 40–60 mm high, attached to Lophelia pertusa , all colonies with female gonothecae .

Biology. Halecium beanii has been usually found growing on hard substrata like rocks and concretions and on algae and other invertebrates ( Gravili et al. 2015). Fertile material has been found throughout the year ( Cornelius 1995a; Gil & Ramil 2017a).

Our material was found growing on L. pertusa . Colonies with female gonothecae were recorded in November.

Distribution. This species shows a near cosmopolitan distribution in shallow to moderately deep waters, with records in all oceans but the Southern Ocean ( Cornelius 1995a; Ramil et al. 1998; Schuchert 2005); its distribution was reviewed in detail by Medel & Vervoort (2000). In West Africa, H. beanii was collected from Morocco ( Patriti 1970), Canary Islands ( Medel & Vervoort 2000), Cape Verde Islands ( Rees & Thursfield 1965), Guinea-Bissau (Vervoort 1959; Gili et al. 1989) and Ghana ( Buchanan 1957). Its bathymetric distribution extends from 0 to 1134 m ( Millard 1978).

Our material was collected from depths of 487 to 642 m.

Remarks. The presence of female gonothecae confirms the identification of this material as H. beanii . Its morphology is very similar to that of Halecium halecinum ( Linnaeus, 1758) , and only the female gonothecae allow accurate separation of both species ( Millard 1975; Ramil & Vervoort 1992; Schuchert 2005).