Eudendrium ramosum ( Linnaeus, 1758 )

Gil, Marta, Ramil, Fran & Agís, José Ansín, 2020, Hydroids (Cnidaria, Hydrozoa) from Mauritanian Coral Mounds, Zootaxa 4878 (3), pp. 412-466 : 420

Eudendrium ramosum ( Linnaeus, 1758)

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

Material examined. MAURIT-0911, stn MU DR01 , 16º08´24”N, 16º57´12”W, 488 m, 5-XII-2009: 25 colonies, badly damaged, some attached to other hydroids and bryozoans .

MAURIT-1011, stn MU DR20 , 16º08´11”N, 16º56´08”W, 405 m, 7-XII-2010: two colonies badly damaged, one colony attached to a sponge and the other attached to Sertularella gayi .

MSM 16 /3, stn GeoB 14802–1, BG, 20°14.791’N, 17°40.188’W, 595 m, 3-XI-2010: two colonies without gonozooids, attached to corals .

MSM 16 /3, stn GeoB 14886–1, ROV, 18°39.013’– 18°38.476’N, 16°43.580’– 16°43.757’W, 484–640 m, 12-XI- 2010: one colony 17 mm high with female gonophores, growing on Acesta excavata .

MSM 16 /3, stn GeoB 14905–1, CKG, 17°32.457’N, 16°39.997’W, 486 m, 15-XI-2010: one colony, without gonozooids .

Biology. This species grows on a wide variety of substrates, especially on hard substrata, algae and as epibiont on other invertebrates ( Peña Cantero & García Carrascosa 2002). Fertile material has been found from March to December ( Peña Cantero & García Carrascosa 2002; Schuchert 2012; Gil & Ramil 2017a).

In our material, some colonies were collected growing on the bivalve A. excavata and the hydroid S. gayi . Female gonophores were observed in November.

Distribution. Eudendrium ramosum was reported as a cosmopolitan species by Bouillon et al. (2006), but many of its records are considered doubtful ( Ramil & Vervoort 1992; Marques et al. 2000; Schuchert 2001; Peña Cantero & García Carrascosa 2002). Schuchert (2012) indicated that all records outside the East Atlantic (Arctic to South Africa, including the Mediterranean) need confirmation. In West Africa, it was collected from Morocco ( Ramil & Vervoort 1992; Vervoort 2006), Canary Islands ( Vervoort 2006), Mauritania ( Gil & Ramil 2017a) and Cape Verde ( Ritchie 1907; Vervoort 2006). The bathymetrical distribution of the species extends from tidal areas ( Ansín Agís 1992) to a depth of 1870 m ( Ramil & Vervoort 1992).

The material studied by us was collected from depths of 484 to 640 m.

Remarks. The study of the nematocysts confirms that our material belongs to E. ramosum .