Hydroids (Cnidaria, Hydrozoa) from Mauritanian Coral Mounds Author Gil, Marta Departamento de Ecoloxía e Bioloxía Animal, Facultade de Ciencias do Mar e Centro de Investigación Mariña (CIM-UVigo), Universidade de Vigo. Campus Lagoas-Marcosende. 36310 Vigo. Spain. & Instituto Español de Oceanografía, Centro Oceanográfico de Vigo. Subida Radio Faro 50. 36390 Vigo. Spain. Author Ramil, Fran Departamento de Ecoloxía e Bioloxía Animal, Facultade de Ciencias do Mar e Centro de Investigación Mariña (CIM-UVigo), Universidade de Vigo. Campus Lagoas-Marcosende. 36310 Vigo. Spain. & framil @ uvigo. es Author Agís, José Ansín Departamento de Ecoloxía e Bioloxía Animal, Facultade de Ciencias do Mar e Centro de Investigación Mariña (CIM-UVigo), Universidade de Vigo. Campus Lagoas-Marcosende. 36310 Vigo. Spain. & ansinjose @ gmail. com text Zootaxa 2020 2020-11-16 4878 3 412 466 journal article 7931 10.11646/zootaxa.4878.3.2 288c6fc9-269b-468f-8811-d79d4350f6e4 1175-5326 4425132 4F59F5B2-CFDB-4819-AF83-0EF232328F8D 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 ).