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 Gargamella immaculata Bergh, 1894 ( Figures 2E, 2F ) Material examined . Argentina , San Matías gulf, Puerto Lobos , two specimens , (MLP-Ma 14578); Río Negro : Isla Mejillón , one specimen , intertidal, 03/11/2017 ; Plataforma, one specimen , 9m , 10/01/2018 ; one specimen , 6 m , 01/20/18. Description . Length up to 30 mm . Body oval, white, yellowish to orange. Dorsum densely covered with caryophyllidia of different sizes, the tips of some white in color. Rhinophores foliated. 8 to 12 bipinnate or tripinnate gill leaves around the anal papilla ( Figure 2E ). The radular formula is 60 x 81.0.81, lateral teeth very dense near the middle of the radula and are smaller towards the external ones. Geographic distribution and depth range . North of Argentina ( 37°50´S , 56°11´W ), Argentinean and Chilean Patagonia to Bahia Coliumo, central Chile ( Schrödl 1997b , 2003 ). Found in soft and intertidal bottoms under rocks up to 15 m depth. Biology . Egg mass is a gelatinous ribbon yellowish about 20 mm long with up to four complete spiral turns, and deposited on rocks ( Figure 2F ). Remarks . The genus Gargamella Bergh, 1894 currently contains seven species. Only one of them is listed for South America, Gargamella inmaculata , since the Chilean species Gargamella latior Odhner, 1926 was included as a junior synonym of G. inmaculata ( Schrödl 2003 ) . This species differs from Gargamella gravastella Valdés & Gosliner, 1999 and Gargamella bovina Garovoy, Valdés & Gosliner, 1999 , from South Africa , by the absence of dark grey mantle color and dense carophyllidia present in G. garvastella . It differs from G. bovina by the absence of the white notum colored with dark brown spots and short caryophyllidia.