Haloa japonica (Pilsbry, 1895) (Figure 2 (a)) Material examined Le Ponton, Étang de Thau, Sète (France), 43°25 ʹ 28.5”N, 3°42 ʹ E, 3 November 2017, 2.1 m depth, 1 spc., adult, L = 20 mm; 14 April 2018, 1.7 m depth, 3 spcs, adults, L = 20–30 mm; 21 May 2018, 1.9 m depth, 8 spcs, adults, L = up to 35 mm. External morphology Shell external, translucent, background colour brown with large orange punctuations. Parapodia darker on top. Head lighter on edge, with darker central part between the eyes. Ecology Found at night on soft bottoms, between Ceramiales algal species and other red algae. Individuals found during April and May 2018 were mating. Distribution Japanese coast (Pilsbry 1895); USA (Hanson et al. 2013; GBIF.org 2021); Italy (Crocetta et al. 2013); Atlantic Spanish coast: Galicia and Cantabria; Mediterranean Spanish coast: Andalucía (Cervera et al. 2004 as Haminoea cadillegenita); Mediterranean French coast (Hanson et al. 2013; this study). Remarks In the marine pools along the French south-eastern Mediterranean coast there are several marine species of Japanese origin, such as the alga wakame [Undaria pinnatifida (Harvey) Suringar, 1873] and the oyster [Magallana gigas (Thunberg, 1793)], so their presence may be caused by aquaculture (e.g. Faasse 2018). Genus Haminoea Turton and Kingston [in Carrington], 1830

Published as part of Salvador, Xavier, Fernández-Vilert, Robert & Moles, Juan, 2022, Sea slug night fever: 39 new records of elusive heterobranchs in the western Mediterranean (Mollusca: Gastropoda), pp. 265-310 in Journal of Natural History 56 (5 - 8) on page 269, DOI: 10.1080/00222933.2022.2040630, http://zenodo.org/record/6758438