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