Checklist of Benthic Cnidaria in the SW Atlantic Ocean (54 ºS- 56 ºS) Author Schejter, L. 0000-0001-5443-4048 Instituto Nacional de Investigación y Desarrollo Pesquero (INIDEP). Paseo Victoria Ocampo 1, 7600, Mar del Plata, Argentina. Instituto de Investigaciones Marinas y Costeras (IIMyC), Consejo Nacional de Investigaciones Científicas y Técnicas, Mar del Plata, Argentina. & schejter @ inidep. edu. ar, https: // orcid. org / 0000 - 0001 - 5443 - 4048 Author Genzano, G. 0000-0002-9818-7648 genzano @ mdp. edu. ar; https: // orcid. org / 0000 - 0002 - 9818 - 7648 genzano@mdp.edu.ar Author Pérez, C. D. 0000-0002-0866-1183 Centro Acadêmico de Vitória, Universidade Federal de Pernambuco, Rua Alto do Reservatório s / n, Bela Vista, CEP: 55608 - 680, Vitória de Santo Antão-PE, Brazil. & carlos. perez @ ufpe. br, https: // orcid. org / 0000 - 0002 - 0866 - 1183 Author Acuña, F. Estación Científica Coiba (Coiba-AIP), Clayton, Panamá, República de Panamá. Author Cordeiro, R. T. S. 0000-0002-3164-5333 Departamento de Biologia, Universidade Federal Rural de Pernambuco, Rua Dom Manuel de Medeiros, s / n, Dois Irmãos, CEP: 52171 - 900, Recife / PE, Brazil. & Department of Invertebrate Zoology, National Museum of Natural History, Smithsonian Institution, Washington, DC, USA ralfts @ gmail. com; https: // orcid. org / 0000 - 0002 - 3164 - 5333 ralfts@gmail.com Author Silva, R. A. Centro Acadêmico de Vitória, Universidade Federal de Pernambuco, Rua Alto do Reservatório s / n, Bela Vista, CEP: 55608 - 680, Vitória de Santo Antão-PE, Brazil. Author Garese, A. Author Bremec, C. S. text Zootaxa 2020 2020-11-13 4878 2 201 239 journal article 7936 10.11646/zootaxa.4878.2.1 b10a81a2-3936-425a-92b6-9e52fd7be1e7 1175-5326 4424884 F930E674-DDA9-4EC9-B0E9-3891B239C6CF Thouarella spp. Material examined: 37 specimens not identified from four diferente morphotypes. BBB 2016: St. 12; St. 13; St. 18; St. 21; St. 28; St. 32; St. 36; St. 38; St. 40. PD BB 17: St. 9; St. 10; St. 16; St. 21; St. 23; St. 27; St. 29; St. 30; St. 43. GARCÍA 15: St. 17; St. 17bis. Distribution: Thouarella is the most speciose genus within the Family Primnoidae , especially diversified in subantarctic waters, mostly in depths from 400 to 5850 m ( Taylor et al. 2013 ). Thouarella spp. were one of the dominant group in the studied area and were recorded at almost all stations ( Schejter et al . 2020 ). Remarks: At least five species of Thouarella were already found in the Burdwood bank area: T. antarctica (Valenciennes, 1846) , T. brucei Thomson & Ritchie, 1906 , T. striata Kükenthal, 1907 , T. chilensis Kükenthal, 1908 , T. viridis Zapata-Guardiola & López-González, 2010 ( Taylor et al. 2013 ); and one is first reported herein: T. variabilis Wright & Studer, 1889 . Two potentially new species were identified from the Marine Protected Areas Namuncurá I and II, which did not fit in any species described so far. There are at least 38 valid Thouarella species ( Núñez-Flores et al . 2020 ); however, as morphological plasticity is common among species of Thouarella , such as in T. variabilis Wright & Studer, 1889 , further assessments (Scanning Electron Micrographies and COI , MutS sequencing) are needed in order to confirm if they are new species and identify at species level the four morphotypes analysed. This fact reinforces the still poorly known octocoral diversity in the region, despite several studies on that fauna.