Nemertesia perrieri ( Billard, 1901 )

Gil, Marta, Ramil, Fran & Agís, José Ansín, 2020, Hydroids (Cnidaria, Hydrozoa) from Mauritanian Coral Mounds, Zootaxa 4878 (3), pp. 412-466 : 452

Nemertesia perrieri ( Billard, 1901)

Antennularia Perrieri Billard, 1901: 73 ; 1906: 211, fig. 15C.

Nemertesia perrieri: Ansín Agís et al., 2001: 211–215 , fig. 82; Peña Cantero & García Carrascosa, 2002: 114–115, fig. 22a–c; Vervoort, 2006: 256.

Nemertesia irregularis: Ramil & Vervoort, 1992:170–173 , fig. 48a; Medel & Vervoort, 1995: 52–56, figs. 22, 23c [not Nemertesia irregularis ( Quelch, 1885) ]

Material examined. MAURIT-0911, stn MUDR02 , 16º08´50”N, 16º57´01”W, 462 m, 5-XII-2009: three colonies, without gonothecae .

Biology. This species was collected in bottoms of mixed sand and mud and on concretions of polychaete tubes ( Medel & Vervoort 1995) and usually provided a suitable substrate for other hydroids ( Peña Cantero & García Carrascosa 2002). Colonies with gonothecae have been found between February and May, July and August ( Ansín Agís et al. 2001; Peña Cantero & García Carrascosa 2002; Gil & Ramil 2017a).

Distribution. Nemertesia perrieri is a Lusitanian species, recorded from Belle-Ile (NW France) to Senegal, including the Mediterranean Sea. In West Africa, N. perrieri was collected from Morocco ( Ramil & Vervoort 1992, as N. irregularis ; Ansín Agís et al. 2001), Canary Islands ( Ansín Agís et al. 2001), Mauritania ( Ansín Agís et al. 2001; Gil & Ramil 2017a) and Senegal (Vervoort 1959). Its bathymetric range extends from 5 to 1387 m ( Ansín Agís et al. 2001; Peña Cantero & García Carrascosa 2002; Gil & Ramil 2017a). The records of N. perrieri from Sagami Bay, Japan ( Stechow 1907, as Antennularia dendritica Stechow, 1907 ; Stechow 1909, as Antennularia Perrieri ) are here considered doubtful and need to be confirmed with new data.

Our material was collected from a depth of 462 m.

Remarks. The absence of nematothecae on the hydrocaulus and presence of two nematothecae on the ahydrothecate internodes allowed us to identify this species. The presence of ahydrothecate internodes with only one nematotheca is always related to the process of regeneration of internodes after damage ( Ansín Agís et al. 2001).