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 54187 10.11646/zootaxa.5244.5.3 bca5397b-9bb5-4b55-a9e0-302523ff937c 1175-5326 7663830 21F87739-7A95-4A6C-8887-A8E22A40120A Doris fontainii d'Orbigny, 1837 ( Figures 2A , 3A ) Material examined. Argentina , San Matías gulf, Caleta Los Hornitos , BENTOS 2008, two specimens (MLP-Ma 14653); Río Negro : Las Grutas , REDE 2009 , one specimen , 15 m , 2011; San Antonio Este, Punta Villarino, five specimens ( MACN 13367 ); San Matías gulf, one, three and seven specimens ( MACN 21309 , MACN 21310 and MACN 21308 , respectively) . Description . Length up to 70 mm , body oval, color varies from pale to dark yellow. Dorsal area covered by large tubercles that become smaller towards the edge of the mantle. Lamellate rhinophores, wide base and around 30 lamellae. Gill with 5-7 multipennate leaves around the anal papilla ( Figure 2A ). Radular formula is 35 x 63.0.63 (MLP-Ma 14653). Lateral teeth curved without denticles ( Figure 3A ). Geographic distribution and depth range . Argentina , from San Antonio Cape ( Valdés & Muniain 2002 ); Arica, Chile (Schrödl 2000) to Islote Ferrol ( 09°08′22″S ; 78°37′15″W ), Ancash , Peru ( Araya & Valdés 2016 ). Usually found under rocks between six and 20 m depth . Remarks . Doris fontainii is easily recognizable due to its large size, the bright yellow color of its body and a mantle covered with conspicuous tubercles. Some of the examined specimens present dark brown pigment between the tubercles which Schrödl et al. (2005) described as a characteristic of central and northern Chilean specimens.