Eudendrium ramosum ( Linnaeus, 1758 )

Gil, Marta & Ramil, Fran, 2025, Hydroids (Cnidaria, Hydrozoa) from Guinea Bissau, Zootaxa 5577 (1), pp. 1-89 : 16

Eudendrium ramosum ( Linnaeus, 1758)

Tubularia ramosa Linnaeus, 1758: 804 .

Eudendrium ramosum : Ramil & Vervoort, 1992a: 20–21.— Schuchert, 2001: 32–33, fig. 20.— Peña Cantero & García Carrascosa, 2002: 37–38, fig. 7A–C.— Bouillon et al., 2006: 60–61, fig. 36H–L.— Vervoort, 2006: 215–216, fig. 4 no. 2.— Schuchert, 2012: 322–323, fig. 281.

Material examined. BISSAU-0810, stn BS191, 10º18'25"– 10º19'20"N, 16º08'47"– 16º08'47"W, 24–25 m, 3-XI-2008: 30 colonies, 28–113 mm high, without gonophores, of which two growing on Diphasia digitalis , and one on a polychaete tube.

BISSAU-0810, stn BS192, 10º19'30"– 10º20'15"N, 16º10'27"– 16º10'59"W, 24 m, 3-XI-2008: four colonies, 47–70 mm high, all without gonophores, substrate unknown.

BISSAU-0810, stn BS194, 10º21'59"– 10º22'36"N, 16º13'23"– 16º14'03"W, 21–24 m, 3-XI-2008: five colonies, 24–88 mm high, all without gonophores, substrate unknown.

BISSAU-0810, stn BS195, 10º22'44"– 10º23'22"N, 16º15'37"– 16º16'18"W, 29 m, 3-XI-2008: one colony without gonophores, attached to a bryozoan.

BISSAU-0810, stn BS216, 10º30'53"– 10º31'39"N, 16º31'33"– 16º32'02"W, 56–58 m, 7-XI-2008: one colony without gonophores, epizoic on Nemertesia ramosa .

Remarks. The study of nematocysts allowed us to identify this material as E. ramosum .

Biology. This species has been found growing on hard substrates, whether artificial or organic, such as algae and other invertebrates, e.g. bryozoans, gastropods, bivalves, anthozoans, polychaete tubes and other hydroids ( Peña Cantero & García Carrascosa 2002; Gil & Ramil 2021b). In the northern hemisphere, colonies with gonophores have been found between March and December ( Peña Cantero & García Carrascosa 2002; Schuchert 2012; Gil & Ramil 2017a), while in the southern hemisphere, fertile material was found in February ( Gil & Ramil 2021b).

In our material, E. ramosum was found growing on D. digitalis , N. ramosa , a polychaete tube and a bryozoan. Gonophores were not observed.

Distribution. Eudendrium ramosum is considered as a cosmopolitan species; nevertheless, many of its records are doubtful ( Ramil & Vervoort 1992a; Marques et al. 2000), especially those from outside the eastern Atlantic ( Schuchert 2012). In West Africa, it was recorded from Morocco ( Ramil & Vervoort 1992a; Vervoort 2006) to the Cape Verde ( Ritchie 1907; Vervoort 2006), and from the Valdivia Seamount ( Gil & Ramil 2021b). Its bathymetrical range starts from the tidal zone ( Ansín Agís 1992), reaching depths as much as 1870 m ( Ramil & Vervoort 1992a).

The material studied by us was collected at depths between 21–58 m.