Sea slug night fever: 39 new records of elusive heterobranchs in the western Mediterranean (Mollusca: Gastropoda) Salvador, Xavier Fernández-Vilert, Robert Moles, Juan Journal of Natural History 2022 2022-05-18 56 5 - 8 265 310 799DB 2780906 (Quatrefages, 1844) Quatrefages 1844 [434,881,1303,1329] Gastropoda Runcinidae Runcina Animalia Runcinida 27 292 Mollusca species ornata  ( Figure 5(e))   Material examined   Cala d’Aiguafreda, Begur( Spain), 41°57 ʹ49”N, 3°13 ʹ41”E,  13 October 2017,  0.1 mdepth, 7 spcs, adults, L = 2–3 mm;  21 November 2017,  0.1 mdepth, 1 spc., adult, L = 2 mm;  31 January 2018,  0.1 mdepth, 9 spcs, adults, L = 2–3 mm;  23 April 2018,  0.1 mdepth, 2 spcs, adults, L = 3 mm;  25 May 2018,  0.1 mdepth, 2 spcs, adults, L = 3 mm;  Punta del Romaní, L’Escala( Spain), 42°6 ʹ54”N. 3°10 ʹ9”E,  10 January 2018,  0.2 mdepth, 4 spcs, adults, L = 2–3 mm;  24 April 2018,  0.2 mdepth, 3 spcs, adults, L = 2–3 mm;  7 December 2018,  0.2 mdepth, 7 spcs, adults, L = 2–3 mm; Punta d’en Bosch, Sant Feliu de Guíxols( Spain), 41°45 ʹ54”N, 3°0 ʹ11”E,  17 April 2018,  0.1 mdepth, 5 spcs, adults, L = 1–3 mm.  External morphology Body elongate, narrow, black or brown in colour, rear tail darker. Foot large.   Ecology Specimens found grazing on biofouling at night over calcarean red algae or boulders, in very superficial waters.   Distribution Atlantic Spanish coast: Canary Islands and Strait of Gibraltar( Cervera et al. 2004) and Mediterranean Spanish coast: Catalonia (this study).   Remarks This species is rarely observed and very small. Easily distinguishable from other  Runcinaspeciesby its absence of spots and white marks and its uniform black colour ( Quatrefages 1844). Superorder SACOGLOSSA Ihering, 1876 Family HERMAEIDAE H. Adams and A. Adams, 1854 Genus  AplysiopsisDeshayes, 1853 3819588382 2017-10-13 2017-11-21 2017-10-13 Spain 1 41.96361 Cala d'Aiguafreda 19 3.2280555 Begur 27 292 1 3819588315 2017-10-13 2017-11-21 2017-10-13 Spain 1 41.96361 Cala d'Aiguafreda 19 3.2280555 Begur 27 292 1 3819588331 2017-10-13 2017-11-21 2017-10-13 Spain 1 41.96361 Cala d'Aiguafreda 19 3.2280555 Begur 27 292 1