Limapontia capitata (O.F. Müller, 1774)

(Figure 6 (d))

Material examined

Le Ponton, Étang de Thau, Sète (France), 43°25 ʹ 28.5”N, 3°42 ʹ E, 18 May 2017, 1 m depth, 2 spcs, adults, L = 3 mm .

External morphology

Body short, thick, background colour dark brown, periocular area and tail white. Rhinophores very short, crest-like. Parapodia absent. Protuberance caused by pericardial system seen in dorsum.

Ecology

Specimens found in brackish waters on substrate extensively covered by the green alga Ulva lactuca Linnaeus, 1753 .

Distribution

Originally described in the North Sea (England and Norway; Muller 1773); also, Portugal (Cervera et al. 2004); Spain: Cantabric Sea, Galicia, Levantine coast (Templado et al. 1983; Cervera et al. 2004); Mediterranean French coast (this study).

Remarks

This species has been reported from eutrophic areas with variable salinity, although its presence has been attributed to having been washed there by waves (Rudman 2021). It has always been found with green algae of the genera Cladophora, Ulva and Bryopsis . It can be distinguished from L. senestra (Quatrefages, 1844) because it lacks long cephalic extensions, and from L. depressa Alder and Hancock, 1862 because of its particular head shape (Gascoigne 1952).

Genus Placida Trinchese, 1876