Sea slug night fever: 39 new records of elusive heterobranchs in the western Mediterranean (Mollusca: Gastropoda) Author Salvador, Xavier 0000-0003-3039-7566 Author Fernández-Vilert, Robert 0000-0002-2812-4414 Author Moles, Juan 0000-0003-4511-4055 text Journal of Natural History 2022 2022-05-18 56 5 - 8 265 310 http://dx.doi.org/10.1080/00222933.2022.2040630 journal article 10.1080/00222933.2022.2040630 38f6df24-838f-409a-90df-b56087e6a9bc 1464-5262 6758438 Aegires sublaevis Odhner, 1932 ( Figure 2 (f)) Material examined Cala Maset caves, Sant Feliu de Guíxols ( Spain ), 41°47 ʹ 10”N , 3°2 ʹ 44”E , 16 February 2018 , 1 m depth , 1 spc ., adult, L = 15 mm . External morphology Body elongate, rough, angulated with central part of dorsum flattened, with black marks on dorsum and laterals; body colour variable white to yellow. Branchial leaves protected by three tubercles, the central one larger than the laterals. Rhinophores smooth, having a brown ring close to the top. Ecology One specimen was found feeding on white calcareous sponges of the genus Ascandra Haeckel, 1872 and, thus, displaying the same white colouration as the sponge. Distribution Madeira ( Malaquias et al. 2001 ); Azores ( Calado 2002 ; Fahey and Gosliner 2004 ); Atlantic Spanish coast: Canary Islands ( Odhner 1931 ; Altimira and Ros 1979 , as Serigea sublaevis ; Pérez Sánchez et al. 1990 ; Ortea et al. 1996 ; 2001 , 2003; Malaquias and Calado 1997 ), Mediterranean Spanish coast: Levantine coast ( Templado et al. 1987 ), and Catalonia (this study). Remarks According to Ortea et al. (1996) , the colouration of this species varies from yellow to beige or white depending on the diet. Slugs are generally found feeding on Clathrina coriacea (Montagu, 1814) . Family CADLINIDAE Bergh, 1891 Genus Aldisa Bergh, 1878