Cyerce graeca Thompson T., 1988

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 : 295

Cyerce graeca Thompson T., 1988

( Figure 5 (h))

Material examined

Cala d’Aiguafreda , Begur ( Spain), 41°57 ʹ 49”N, 3°13 ʹ 41”E, 26 August 2015, 0.5 m depth, 1 spc ., adult, L = 15 mm; 3 August 2017, 2.3 m depth, 1 spc., adult; Cala Ventosa , Sant Feliu de Guíxols ( Spain), 41°47 ʹ 5”N, 3°2 ʹ 52”E, 13 September 2017, 1.3 m depth, 1 spc ., adult; Cala Maset caves, Sant Feliu de Guíxols ( Spain), 41°47 ʹ 10”N, 3°2 ʹ 44”E, 29 January 2018, 1.2 m depth, 1 spc ., adult; 14 February 2018, 0.7 m depth, 1 spc., juvenile, L = 3 mm; 22 February 2019, 1 m depth, 1 spc., adult, L = 12 mm; 20 February 2020, 0.7 m depth, 1 spc., adult, L = 10 mm.

External morphology

Body elongate, thick, background colour transparent to beige with darker dorsum. Cerata rounded, globular, beige to semi-transparent in colour, with blunt and dark brown digitations on top and white dots concentrated under these digitations. Rhinophores divided into a ‘Y’ shape.

Ecology

Specimens found on unidentified red algae; juveniles were found in February. Slugs were active at night and usually under rocks in areas with abundant algae during the day.

Distribution

Originally described from Greece (Thompson 1988); the Adriatic Sea and Italy (Ballesteros et al. 2012–2021); Spain: Balearic Islands (GROC 2009–2021), Catalonia ( Ballesteros et al. 2016; this study).

Remarks

Easily differentiated from other Mediterranean Cyerce species by its rounded parapodial margin and digitate cerata tips, whereas C. cristallina has an angular parapodial margin and roughened but not digitated cerata apexes (Thompson 1988).

Genus Hermaea Lovén, 1844

Figures

Figure 5. Photographs of live Pteropoda species: (a) Creseis virgula. (b) Hyalocylis striata. (c) Peracle reticulata. (d) Pneumodermopsis canephora. Runcinida: (e) Runcina ornata. Sacoglossa: (f) Aplysiopsis elegans. (g) Caliphylla mediterránea. (h) Cyerce graeca.