Nudibranchia (Mollusca: Gastropoda) from San Matías Gulf, Northern Argentine Patagonia Author Cetra, Nicolás Escuela Superior de Ciencias Marinas (ESCiMar), San Martín 247, San Antonio Oeste, Río Negro, Argentina. Author Roche, Andrea Escuela Superior de Ciencias Marinas (ESCiMar), San Martín 247, San Antonio Oeste, Río Negro, Argentina. & Centro de Investigación y Transferencia Tecnológica en Recursos Marinos Almirante Storni (CIMAS), Güemes 1030, San Antonio Oeste, Río Negro, Argentina. text Zootaxa 2023 2023-02-22 5244 5 455 473 http://dx.doi.org/10.11646/zootaxa.5244.5.3 journal article 10.11646/zootaxa.5244.5.3 1175-5326 7663830 21F87739-7A95-4A6C-8887-A8E22A40120A Spurilla braziliana ( MacFarland, 1909 ) ( Figures 4E, 4F , 5H ) Material examined . Argentina , Río Negro : Caleta Los Hornitos , 15 specimens , intertidal, 18/12/2016 ( two specimens deposited, MLP-Ma 14659); four specimens , intertidal, 03/02/2017 ; San Antonio Este , one specimen , intertidal, 24/08/2016 (ESCM-Ma-79); Fuerte Argentino , two specimens , intertidal, 03/03/2011 (ESCM-Ma-81); El Buque , two specimens , intertidal, 15/06/2016 (ESCM-Ma-31); Bahía San Antonio , two specimens , intertidal, 28/05/2016 (ESCM-Ma-32); Plataforma ; one specimen , 12 m , 03/2017 (ESCM-Ma-80); Chubut , Puerto Lobos, one specimen (MLP-Ma 13108) . Description . Length up to 50 mm , body elongated, orange. Rhinophores lamellate, with a white apex. Cerata arranged in 6 to 9 arches, with the tips clearer and curved towards the dorsal area of the body. Digestive glands are visible in the cerata ( Figure 4E ). Radular formula 23 x 0.1.0. (MLP-Ma 14659). Teeth progressively smaller in the posterior region of the radula. Rachidian teeth bicurved, with between 55 to 70 denticles on each side of the central, small, and triangular cusp. ( Figure 5H ). Geographic distribution and depth range . Pacific and Atlantic Ocean. Hawaiian Islands, Costa Rica , Peru , Japan , China , and Australia . From Florida to Argentinean Patagonian ( Carmona et al. 2014 ). San Matías gulf, Argentina (Ģller & Zelaya 2017 ). Found in soft and intertidal bottoms under rocks up to 10 m depth. Biology . The egg mass is a spiral white ribbon, about 30 mm in length. The egg masses are deposited on the rocks ( Figure 4F ). Remarks . This species has often been recorded under the name Spurilla neapolitana (Delle Chiaje 1841) . Externally, the color and morphology are not sufficient to differentiate the two species. Based on genetic data, Carmona et al. (2014) identified the southwestern Atlantic species as S. braziliana .