Elysia flava Verrill, 1901

Salvador, Xavier, Fernández-Vilert, Robert & Moles, Juan, 2022, Sea slug night fever: 39 new records of elusive heterobranchs in the western Mediterranean (Mollusca: Gastropoda), Journal of Natural History 56 (5 - 8), pp. 265-310 : 301

Elysia flava Verrill, 1901

( Figure 6 (g))

Material examined

Cala d’Aiguafreda , Begur ( Spain), 41°57 ʹ 49”N, 3°13 ʹ 41”E, 30 July 2015, 2.3 m depth, 6 spcs, adults, L = 5–12 mm; Roqueo de los 14, La Herradura ( Spain), 36°43 ʹ 13.2”N, 3°43 ʹ 43.5”W, 18 September 2016, 1.6 m depth, 3 spcs, adults, L = 7–10 mm .

External morphology

Body elongate, narrow, background colour green/yellow, dark green in parapodia, margin of parapodia wavy, white. Rhinophores short, apex white, with two white spots between eyes.

Ecology

Specimens found in July mating on unidentified algae. This species is strictly nocturnal, found during the day under rocks and at night on algae, especially green filamentous algae such as Cladophora .

Distribution

Caribbean Sea (GBIF.org 2021); Madeira ( Cervera et al. 2004); Azores ( Malaquias et al. 2009); Greece and Adriatic Sea (Ballesteros et al. 2012–2021); Spain: Canary Islands, Levantine coast, Catalonia ( Cervera et al. 2004; this study), Andalucía (this study).

Remarks

This species is differentiated from sympatric Elysia by the yellowish colour of the body as well as the green dark colour in the parapodia ( Thompson and Jaklin 1988).

Superorder SIPHONARIMORPHA

Family SIPHONARIIDAE Gray, 1827

Genus Williamia Monterosato, 1884

Figures

Figure 6. Photographs of live Sacoglossa species: (a) Hermaea bifida and close-up on its egg mass at the base of an alga. (b) Hermaea cantabra. (c) Hermaea paucicirra. (d) Limapontia capitata on Ulva lactuca. (e) Placida tardyi. (f) Placida viridis. (g) Elysia flava. Siphonariidae: (h) Williamia gussoni.