taxonID	type	description	language	source
024087ABD848D1329ABA26E1FC08FA3E.taxon	description	(Figure 2 (a ))	en	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): 265-310, DOI: 10.1080/00222933.2022.2040630, URL: http://dx.doi.org/10.1080/00222933.2022.2040630
024087ABD848D1329ABA26E1FC08FA3E.taxon	materials_examined	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.	en	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): 265-310, DOI: 10.1080/00222933.2022.2040630, URL: http://dx.doi.org/10.1080/00222933.2022.2040630
024087ABD848D1329ABA26E1FC08FA3E.taxon	biology_ecology	Ecology Found at night on soft bottoms, between Ceramiales algal species and other red algae. Individuals found during April and May 2018 were mating.	en	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): 265-310, DOI: 10.1080/00222933.2022.2040630, URL: http://dx.doi.org/10.1080/00222933.2022.2040630
024087ABD848D1329ABA26E1FC08FA3E.taxon	distribution	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).	en	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): 265-310, DOI: 10.1080/00222933.2022.2040630, URL: http://dx.doi.org/10.1080/00222933.2022.2040630
024087ABD848D1329ABA26E1FC08FA3E.taxon	discussion	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	en	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): 265-310, DOI: 10.1080/00222933.2022.2040630, URL: http://dx.doi.org/10.1080/00222933.2022.2040630
024087ABD848D1339A5C22E7FCE5FB2E.taxon	description	(Figure 2 (b, c ))	en	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): 265-310, DOI: 10.1080/00222933.2022.2040630, URL: http://dx.doi.org/10.1080/00222933.2022.2040630
024087ABD848D1339A5C22E7FCE5FB2E.taxon	materials_examined	Material examined Cala Maset caves, Sant Feliu de Guíxols (Spain), 41 ° 47 ʹ 10.5 ” N, 3 ° 2 ʹ 44.6 ” E, 16 October 2017, 0.6 m depth,> 40 spcs, juveniles, adults and egg masses, L = 2 – 15 mm; 31 December 2017, 1.2 m depth, 3 spcs, juveniles and adults, L = up to 15 mm; Le Ponton, Étang de Thau, Sète (France), 43 ° 25 ʹ 28.5 ” N, 3 ° 42 ʹ E, 3 November 2017, 1.4 m depth, 2 spcs, adults, L = 20 mm; Fòrum pools, Barcelona (Spain), 41 ° 24 ʹ 34.5 ” N, 2 ° 13 ʹ 36.8 ” E, 25 November 2017, 1.7 m depth, 2 spcs, adults and egg masses, L = 20 mm; 27 April 2018, 0.8 m depth, 1 spc., adult, L = 10 mm; l’Espigó, Roses (Spain), 42 ° 15 ʹ 39.8 ” N, 3 ° 10 ʹ 26.8 ” E, 28 February 2020, 0.8 m depth, 5 spcs, adults and egg masses, L = 25 mm. External morphology Shell external, translucent, background colour light brown to grey with dark brown, white and orange punctuations surrounded by small dark red points. Parapodia lighter in colour. Head lighter in colour, area around eyes pigmented.	en	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): 265-310, DOI: 10.1080/00222933.2022.2040630, URL: http://dx.doi.org/10.1080/00222933.2022.2040630
024087ABD848D1339A5C22E7FCE5FB2E.taxon	biology_ecology	Ecology Specimens were found crawling on calcareous rocks with green algae of undetermined species during night samplings. Egg masses were observed in November and juveniles in December 2017. Egg masses elongated, forming a ‘ C’, with white eggs (Figure 1 (c )).	en	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): 265-310, DOI: 10.1080/00222933.2022.2040630, URL: http://dx.doi.org/10.1080/00222933.2022.2040630
024087ABD848D1339A5C22E7FCE5FB2E.taxon	distribution	Distribution Azores, Atlantic Spanish coast: Canary Islands; Mediterranean Spanish coast: Andalucía, Levantine coast (Cervera et al. 2004), Catalonia (this study); Mediterranean French coast (Garabedian et al. 2017; this study); Greece and Italy (Garabedian et al. 2017).	en	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): 265-310, DOI: 10.1080/00222933.2022.2040630, URL: http://dx.doi.org/10.1080/00222933.2022.2040630
024087ABD848D1339A5C22E7FCE5FB2E.taxon	discussion	Remarks Haminoea species in the Mediterranean are understudied (Crocetta et al. 2015; Micaroni et al. 2018) and, thus, all morphological characters that may be useful in distinguishing species are not always clear. One visible distinguishing feature of this species is the presence of a pigmented periocular area. The presence of small orange dots under the shell surrounded by smaller dots of dark purple or black colour, forming a flower pattern, was found in all studied specimens. Family PHILINIDAE Gray, 1850 (1815) Genus Philine Ascanius, 1772	en	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): 265-310, DOI: 10.1080/00222933.2022.2040630, URL: http://dx.doi.org/10.1080/00222933.2022.2040630
024087ABD849D1309ADB23F1FE1FFDDD.taxon	description	(Figure 2 (d ))	en	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): 265-310, DOI: 10.1080/00222933.2022.2040630, URL: http://dx.doi.org/10.1080/00222933.2022.2040630
024087ABD849D1309ADB23F1FE1FFDDD.taxon	materials_examined	Material examined Cala Maset caves, Sant Feliu de Guíxols (Spain), 41 ° 47 ʹ 10 ” N, 3 ° 2 ʹ 44 ” E, 13 December 2017, 1.3 m depth, 1 spc., adults, L = 5 mm; Punta del Romaní, L’Escala (Spain), 42 ° 6 ʹ 54 ” N, 3 ° 10 ʹ 9 ” E, 30 December 2017, 2.5 m depth, 2 spcs, adults, L = 3 – 7 mm; Cala d’Aiguafreda, Begur (Spain), 41 ° 57 ʹ 49 ” N, 3 ° 13 ʹ 41 ” E, 31 January 2018, 1.2 m depth, 1 spc., adult, L = 5 mm.	en	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): 265-310, DOI: 10.1080/00222933.2022.2040630, URL: http://dx.doi.org/10.1080/00222933.2022.2040630
024087ABD849D1309ADB23F1FE1FFDDD.taxon	description	External morphology Body elongate, narrow, white-beige or brown, with a discontinuous dark brown band over cephalic shield. Cephalic shield longer than shell. Parapodia short, not overlapping. Shell completely covered by mantle. Individuals likely hide in the sediment during the day and are active at night.	en	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): 265-310, DOI: 10.1080/00222933.2022.2040630, URL: http://dx.doi.org/10.1080/00222933.2022.2040630
024087ABD849D1309ADB23F1FE1FFDDD.taxon	biology_ecology	Ecology Specimens were found crawling at night on rocks with algae and sediment between rocky outcrops.	en	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): 265-310, DOI: 10.1080/00222933.2022.2040630, URL: http://dx.doi.org/10.1080/00222933.2022.2040630
024087ABD849D1309ADB23F1FE1FFDDD.taxon	distribution	Distribution North Sea (GBIF. org 2021); Azores (Cervera et al. 2004); Portugal (Cervera et al. 2004); Italy and Croatia (Zenetos et al. 2016); Greece (Crocetta et al. 2015); Atlantic Spanish coast: Galicia and Cantabria (Cervera et al. 2004); Mediterranean Spanish coast: Catalonia (this study).	en	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): 265-310, DOI: 10.1080/00222933.2022.2040630, URL: http://dx.doi.org/10.1080/00222933.2022.2040630
024087ABD849D1309ADB23F1FE1FFDDD.taxon	discussion	Remarks Molecular and morphological data indicate that this species may not belong to the genus Philine (J. Moles unpubl. data).	en	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): 265-310, DOI: 10.1080/00222933.2022.2040630, URL: http://dx.doi.org/10.1080/00222933.2022.2040630
024087ABD84AD1319A38240CFB9AFE87.taxon	description	(Figure 2 (e ))	en	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): 265-310, DOI: 10.1080/00222933.2022.2040630, URL: http://dx.doi.org/10.1080/00222933.2022.2040630
024087ABD84AD1319A38240CFB9AFE87.taxon	materials_examined	Material examined Cala Ventosa, Sant Feliu de Guíxols (Spain), 41 ° 47 ʹ 5 ” N, 3 ° 2 ʹ 52 ” E, 13 September 2017, 1 m depth, 1 spc., adult, L = 10 mm; Cala Maset caves, Sant Feliu de Guíxols (Spain), 41 ° 47 ʹ 10 ” N, 3 ° 2 ʹ 44 ” E, 7 May 2018, 1 m depth, 7 spcs, juveniles and adults, L = 3 – 15 mm; Cala d’Aiguafreda, Begur (Spain), 41 ° 57 ʹ 49 ” N, 3 ° 13 ʹ 41 ” E, 25 May 2018, 1 m depth, 6 spcs, juveniles and adults, L = 6 – 15 mm. External morphology Body elongate, rough, angulated, with tubercles in the laterals; body colour beige, with small white and light brown dots; rhinophores, rhinophoral sheaths and apical part of tubercles with dark brown spots. Branchial leaves protected by three tubercles, curved internally, equal in length.	en	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): 265-310, DOI: 10.1080/00222933.2022.2040630, URL: http://dx.doi.org/10.1080/00222933.2022.2040630
024087ABD84AD1319A38240CFB9AFE87.taxon	biology_ecology	Ecology All specimens were found on top of white calcareous sponges of the genus Sycon Risso, 1817 (pss. S. elegans (Bowerbank, 1845) and S. raphanus Schmidt, 1862) and Ascandra contorta (Bowerbank, 1866). Generally found at night at the entrance to or inside caves, crawling on walls.	en	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): 265-310, DOI: 10.1080/00222933.2022.2040630, URL: http://dx.doi.org/10.1080/00222933.2022.2040630
024087ABD84AD1319A38240CFB9AFE87.taxon	distribution	Distribution Sardinia, Italy (Trainito and Doneddu 2015); Mediterranean Spanish coast: Andalucía and Levantine coast (Cervera et al. 2004), Catalonia (Cervera et al. 2004; Ballesteros et al. 2012 – 2021; this study).	en	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): 265-310, DOI: 10.1080/00222933.2022.2040630, URL: http://dx.doi.org/10.1080/00222933.2022.2040630
024087ABD84AD1319A38240CFB9AFE87.taxon	discussion	Remarks This species can be differentiated from the other Atlantic species of Aegires by the shape and disposition of the tubercles around the gills and the dorsum, by the body colour, and by the dark brown dots in the sheaths and apex of the rhinophores (Ortea et al. 1990).	en	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): 265-310, DOI: 10.1080/00222933.2022.2040630, URL: http://dx.doi.org/10.1080/00222933.2022.2040630
024087ABD84BD1319AA52675FCE8FA2B.taxon	description	(Figure 2 (f ))	en	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): 265-310, DOI: 10.1080/00222933.2022.2040630, URL: http://dx.doi.org/10.1080/00222933.2022.2040630
024087ABD84BD1319AA52675FCE8FA2B.taxon	materials_examined	Material examined Cala Maset caves, Sant Feliu de Guíxols (Spain), 41 ° 47 ʹ 10 ” N, 3 ° 2 ʹ 44 ” E, 16 February 2018, 1 m depth, 1 spc., adult, L = 15 mm. External morphology Body elongate, rough, angulated with central part of dorsum flattened, with black marks on dorsum and laterals; body colour variable white to yellow. Branchial leaves protected by three tubercles, the central one larger than the laterals. Rhinophores smooth, having a brown ring close to the top.	en	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): 265-310, DOI: 10.1080/00222933.2022.2040630, URL: http://dx.doi.org/10.1080/00222933.2022.2040630
024087ABD84BD1319AA52675FCE8FA2B.taxon	biology_ecology	Ecology One specimen was found feeding on white calcareous sponges of the genus Ascandra Haeckel, 1872 and, thus, displaying the same white colouration as the sponge.	en	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): 265-310, DOI: 10.1080/00222933.2022.2040630, URL: http://dx.doi.org/10.1080/00222933.2022.2040630
024087ABD84BD1319AA52675FCE8FA2B.taxon	distribution	Distribution Madeira (Malaquias et al. 2001); Azores (Calado 2002; Fahey and Gosliner 2004); Atlantic Spanish coast: Canary Islands (Odhner 1931; Altimira and Ros 1979, as Serigea sublaevis; Pérez Sánchez et al. 1990; Ortea et al. 1996; 2001, 2003; Malaquias and Calado 1997), Mediterranean Spanish coast: Levantine coast (Templado et al. 1987), and Catalonia (this study).	en	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): 265-310, DOI: 10.1080/00222933.2022.2040630, URL: http://dx.doi.org/10.1080/00222933.2022.2040630
024087ABD84BD1319AA52675FCE8FA2B.taxon	discussion	Remarks According to Ortea et al. (1996), the colouration of this species varies from yellow to beige or white depending on the diet. Slugs are generally found feeding on Clathrina coriacea (Montagu, 1814). Family CADLINIDAE Bergh, 1891 Genus Aldisa Bergh, 1878	en	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): 265-310, DOI: 10.1080/00222933.2022.2040630, URL: http://dx.doi.org/10.1080/00222933.2022.2040630
024087ABD84BD13E9A0322FCFCFDFC36.taxon	description	(Figure 2 (g ))	en	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): 265-310, DOI: 10.1080/00222933.2022.2040630, URL: http://dx.doi.org/10.1080/00222933.2022.2040630
024087ABD84BD13E9A0322FCFCFDFC36.taxon	materials_examined	Material examined Cala d’Aiguafreda, Begur (Spain), 41 ° 57 ʹ 49 ” N, 3 ° 13 ʹ 41 ” E, 24 April 2015, 3 m depth, 1 spc., L = 7 mm. External morphology Body rounded, flat; light red, with two dark circles on dorsum; yellow-brown line present at laterals of body next to the first circle. Gills light red, white at tips of branchial leaves.	en	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): 265-310, DOI: 10.1080/00222933.2022.2040630, URL: http://dx.doi.org/10.1080/00222933.2022.2040630
024087ABD84BD13E9A0322FCFCFDFC36.taxon	biology_ecology	Ecology A single specimen was found at a shallow depth under a rock, on top of the sponge Phorbas topsenti Vacelet and Pérez, 2008.	en	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): 265-310, DOI: 10.1080/00222933.2022.2040630, URL: http://dx.doi.org/10.1080/00222933.2022.2040630
024087ABD84BD13E9A0322FCFCFDFC36.taxon	distribution	Distribution Atlantic Spanish coast: Canary Islands (Pruvot-Fol 1953, as Aldisa binotata; Ortea et al. 1982); Mediterranean Spanish coast: Catalonia (this study).	en	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): 265-310, DOI: 10.1080/00222933.2022.2040630, URL: http://dx.doi.org/10.1080/00222933.2022.2040630
024087ABD84BD13E9A0322FCFCFDFC36.taxon	discussion	Remarks In the original description the body was described as red with two large dark circles and a white line just after the first dark circle (Ortea et al. 1982). The specimen studied here has lighter red colouration and lacks the second dark circle. The gills are also light red and white on the top, while the conspecific A. banyulensis (Pruvot-Fol, 1951) has dark red gills, lacking the white top. Moreover, our specimen has a yellow line in the anterior part of the body, anterior to the first dot, while in A. banyulensis the yellow line is found between the first and second dots, displayed slightly towards the posterior part. Family GONIODORIDIDAE H. Adams and A. Adams, 1854 Genus Okenia Menke, 1830	en	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): 265-310, DOI: 10.1080/00222933.2022.2040630, URL: http://dx.doi.org/10.1080/00222933.2022.2040630
024087ABD844D13C9BCB249FFCF2FDA2.taxon	description	(Figure 2 (h ))	en	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): 265-310, DOI: 10.1080/00222933.2022.2040630, URL: http://dx.doi.org/10.1080/00222933.2022.2040630
024087ABD844D13C9BCB249FFCF2FDA2.taxon	materials_examined	Material examined Cala Maset caves, Sant Feliu de Guíxols (Spain), 41 ° 47 ʹ 10 ” N, 3 ° 2 ʹ 44 ” E, 23 September 2016, 1 m depth, 5 spcs, juveniles, adults and egg masses, L = 2 – 8 mm; 14 September 2017, 1 m depth, 7 spcs, adults and egg masses, L = 5 – 13 mm; 16 October 2017, 1 m depth,> 20 spcs, adults and egg masses, L = 7 – 13 mm; Cala Ventosa, Sant Feliu de Guíxols (Spain), 41 ° 47 ʹ 5 ” N, 3 ° 2 ʹ 52 ” E, 13 September 2017, 1 m depth, 2 spcs, adults and egg masses, L = 5 mm; Fòrum pools, Barcelona (Spain), 41 ° 24 ʹ 34.5 ” N, 2 ° 13 ʹ 36.8 ” E, 23 November 2017, 2.3 m depth, 7 spcs, adults and egg masses, L = 5 – 10 mm.	en	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): 265-310, DOI: 10.1080/00222933.2022.2040630, URL: http://dx.doi.org/10.1080/00222933.2022.2040630
024087ABD844D13C9BCB249FFCF2FDA2.taxon	description	External morphology Body elongate, narrow, background colour light brown or white with irregular brown, black and white punctuations in adults. Papillae smooth, found scattered on dorsum and laterals. Rhinophores present a smooth front surface, lamellar in back. Discoidal branchial leaves.	en	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): 265-310, DOI: 10.1080/00222933.2022.2040630, URL: http://dx.doi.org/10.1080/00222933.2022.2040630
024087ABD844D13C9BCB249FFCF2FDA2.taxon	biology_ecology	Ecology All specimens at each locality were found on the bryozoans Amathia verticillata (Delle Chiaje, 1822), laying their egg masses.	en	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): 265-310, DOI: 10.1080/00222933.2022.2040630, URL: http://dx.doi.org/10.1080/00222933.2022.2040630
024087ABD844D13C9BCB249FFCF2FDA2.taxon	distribution	Distribution Recently reported in Italy and on the Mediterranean French coast (Pola et al. 2019); Mediterranean Spanish coast: Catalonia (Pola et al. 2019; this study).	en	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): 265-310, DOI: 10.1080/00222933.2022.2040630, URL: http://dx.doi.org/10.1080/00222933.2022.2040630
024087ABD844D13C9BCB249FFCF2FDA2.taxon	discussion	Remarks Pola et al. (2019) recently confirmed the differences between this species and O. zoobotryon (Smallwood, 1910), previously recorded in the Mediterranean but originally described from the Islands of Bermuda. Morphological analyses in that study revealed differences in the reproductive system and the gill branches between these two species. Thus, according to Pola et al. (2019), previous records of O. zoobotryon in the Mediterranean are misidentifications of O. longiductis, and O. zoobotryon is only present in the western Atlantic.	en	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): 265-310, DOI: 10.1080/00222933.2022.2040630, URL: http://dx.doi.org/10.1080/00222933.2022.2040630
024087ABD846D13D9AB325E6FDEFFEA4.taxon	description	(Figure 3 (a ))	en	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): 265-310, DOI: 10.1080/00222933.2022.2040630, URL: http://dx.doi.org/10.1080/00222933.2022.2040630
024087ABD846D13D9AB325E6FDEFFEA4.taxon	materials_examined	Material examined Cala Maset caves, Sant Feliu de Guíxols (Spain), 41 ° 47 ʹ 10 ” N, 3 ° 2 ʹ 44 ” E, 16 January 2018, 1.7 m depth, 5 spcs, adults and egg masses, L = 8 – 14 mm; 7 May 2018, 1.4 m depth, 1 spc., adult and egg masses, L = 15 mm; L = 8 – 14 mm; 11 March 2020, 2 m depth, 7 spcs, juveniles. External morphology Body short, thick, background colour black with numerous white papillae. Mantle margin white. Rhinophores with lamellae, beige or white. Branchial leaves dark brown.	en	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): 265-310, DOI: 10.1080/00222933.2022.2040630, URL: http://dx.doi.org/10.1080/00222933.2022.2040630
024087ABD846D13D9AB325E6FDEFFEA4.taxon	biology_ecology	Ecology Specimens were found mating and laying the egg masses on the bryozoans Amathia lendigera (Linnaeus, 1758) at the entrance of a cave, on overhangs. Egg masses were white with a soft brown colour and laid in a ‘ C’ shape over the bryozoans. Juvenile specimens, only found in 2020, were also crawling on A. lendigera. Slugs are more active at night and may go unnoticed by divers and other observers during the day.	en	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): 265-310, DOI: 10.1080/00222933.2022.2040630, URL: http://dx.doi.org/10.1080/00222933.2022.2040630
024087ABD846D13D9AB325E6FDEFFEA4.taxon	distribution	Distribution North Sea (England and Norway; Johnston 1838; Evertsen and Bakken 2013); Mediterranean Spanish coast: Catalonia (Ballesteros et al. 2016; this study).	en	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): 265-310, DOI: 10.1080/00222933.2022.2040630, URL: http://dx.doi.org/10.1080/00222933.2022.2040630
024087ABD846D13D9AB325E6FDEFFEA4.taxon	discussion	Remarks This species apparently has an Amphi-Atlantic and Boreo-Arctic distribution, but its identity may need confirmation since is easily confused with Palio dubia (M. Sars, 1829); therefore, several records may have been misidentified (Thompson and Brown 1984). Genus Polycera Cuvier, 1816	en	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): 265-310, DOI: 10.1080/00222933.2022.2040630, URL: http://dx.doi.org/10.1080/00222933.2022.2040630
024087ABD847D13D9AC42654FCA2F9C6.taxon	description	(Figure 3 (b ))	en	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): 265-310, DOI: 10.1080/00222933.2022.2040630, URL: http://dx.doi.org/10.1080/00222933.2022.2040630
024087ABD847D13D9AC42654FCA2F9C6.taxon	materials_examined	Material examined Le Ponton, Étang de Thau, Sète (France), 43 ° 25 ʹ 28.5 ” N, 3 ° 42 ʹ E, 8 April 2017, 1.2 m depth, 7 spc., adults and egg masses, L = 10 – 25 mm; 4 October 2017, 0.8 m depth, 3 spcs, adults, L = 20 – 25 mm; 21 May 2018, 1.5 m depth, 1 spc., adult, L = 45 mm; 1 November 2018, 1 m depth, 5 spcs, adults and egg masses, L = 15 – 30 mm; l’Espigó, Roses (Spain), 42 ° 15 ʹ 39.8 ” N, 3 ° 10 ʹ 26.8 ” E, 28 February 2020, 0.6 m depth, 8 spcs, adults and egg masses, L = 10 – 20 mm. External morphology Body short, thick, background colour black. Mantle margin white with numerous appendages of black and yellow, yellow close to apex, white papillae scattered all over body. Rhinophores lamellar, black forwards and white backwards, yellow on top. Gill leaves black, tips yellow.	en	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): 265-310, DOI: 10.1080/00222933.2022.2040630, URL: http://dx.doi.org/10.1080/00222933.2022.2040630
024087ABD847D13D9AC42654FCA2F9C6.taxon	biology_ecology	Ecology All specimens in each locality were found in shallow waters on the bryozoan Bugula neritina (Linnaeus, 1758), feeding and laying the egg masses.	en	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): 265-310, DOI: 10.1080/00222933.2022.2040630, URL: http://dx.doi.org/10.1080/00222933.2022.2040630
024087ABD847D13D9AC42654FCA2F9C6.taxon	distribution	Distribution Originally from the north-central Pacific coast of America, this species is reported from Australia, Japan, South Africa, Morocco (Moro et al. 2017); Cantabrian Sea (Cervera et al. 2004); and in the Mediterranean Sea from Italy, Croatia (Servello et al. 2019); France (GBIF. org 2021; this study); and Spain: Catalonia (this study).	en	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): 265-310, DOI: 10.1080/00222933.2022.2040630, URL: http://dx.doi.org/10.1080/00222933.2022.2040630
024087ABD847D13D9AC42654FCA2F9C6.taxon	discussion	Remarks Its bryozoan prey grows on boat hulls, and thus movement via boats could be responsible for this species’ range expansion. However, although this bryozoan is abundant at marine ports, P. hedgpethi has not been recorded in biofouling samples containing B. neritina (X. Salvador pers. obs.). Notably, this species, when found in the Mediterranean, is often in environments with variable salinity, such as the Étang de Thau, or the Espigó de Roses, where there is a fresh water supply. Genus Polycerella A. E. Verrill, 1880	en	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): 265-310, DOI: 10.1080/00222933.2022.2040630, URL: http://dx.doi.org/10.1080/00222933.2022.2040630
024087ABD847D13A9ACC2151FCAEFB72.taxon	description	(Figure 3 (c ))	en	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): 265-310, DOI: 10.1080/00222933.2022.2040630, URL: http://dx.doi.org/10.1080/00222933.2022.2040630
024087ABD847D13A9ACC2151FCAEFB72.taxon	materials_examined	Material examined Cala Maset caves, Sant Feliu de Guíxols (Spain), 41 ° 47 ʹ 10 ” N, 3 ° 2 ʹ 44 ” E, 23 August 2017, 1 m depth, 11 spcs, juveniles, adults and egg masses, L = 2 – 5 mm; Alfacs mussel farms, Sant Carles de la Ràpita, Montsià (Spain), 40 ° 37 ʹ 20.1 ” N, 0 ° 39 ʹ 48.5 ” E, 12 September 2018, 0.7 m depth,> 20 spcs, adults and egg masses, L = 4 – 5 mm; le Ponton, Étang de Thau, Sète (France), 43 ° 25 ʹ 28.5 ” N, 3 ° 42 ʹ E, 1 November 2018, 1.2 m depth, 7 spc., adults and egg masses, L = 5 – 7 mm. External morphology Body short, narrow, background colour white with irregular black and white-yellow punctuation. Gills composed of three leaves, with short, smooth papillae found on dorsum and body laterals. Rhinophores smooth.	en	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): 265-310, DOI: 10.1080/00222933.2022.2040630, URL: http://dx.doi.org/10.1080/00222933.2022.2040630
024087ABD847D13A9ACC2151FCAEFB72.taxon	biology_ecology	Ecology All specimens at each locality were found on the bryozoan Amathia verticillata (Delle Chiaje, 1822) where they laid egg masses.	en	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): 265-310, DOI: 10.1080/00222933.2022.2040630, URL: http://dx.doi.org/10.1080/00222933.2022.2040630
024087ABD847D13A9ACC2151FCAEFB72.taxon	distribution	Distribution Species originally from the east coast of North America (GBIF. org 2021); Pacific coast of North America (Terrence 1988); now found in Morocco, Portugal and the south of Spain (Cervera et al. 2004); Italy (Servello et al. 2019); Greece (Crocetta et al. 2017); France (this study) and Catalonia (Camps and Prado 2018; this study).	en	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): 265-310, DOI: 10.1080/00222933.2022.2040630, URL: http://dx.doi.org/10.1080/00222933.2022.2040630
024087ABD847D13A9ACC2151FCAEFB72.taxon	discussion	Remarks Originally described from the North American Atlantic coast (Verrill 1881), this species has been reported from the American Atlantic and Pacific coasts, and the Mediterranean Spanish, Italian, Greek and African coasts. Its bryozoan prey is commonly found attached to boat hulls. In the case of the specimens found in Catalonia, it was found in ports, bays and eutrophic locations. Genus Thecacera J. Fleming, 1828	en	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): 265-310, DOI: 10.1080/00222933.2022.2040630, URL: http://dx.doi.org/10.1080/00222933.2022.2040630
024087ABD840D13B9ACE222CFCAFFCD2.taxon	description	(Figure 3 (d ))	en	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): 265-310, DOI: 10.1080/00222933.2022.2040630, URL: http://dx.doi.org/10.1080/00222933.2022.2040630
024087ABD840D13B9ACE222CFCAFFCD2.taxon	materials_examined	Material examined Cala Maset caves, Sant Feliu de Guíxols (Spain), 41 ° 47 ʹ 10 ” N, 3 ° 2 ʹ 44 ” E, 14 February 2018, 1.5 m depth, 1 spc., adult, L = 20 mm. External morphology Body short, thick, background colour white with numerous black and yellow dots. Rhinophores lamellar, protected by two papillae, the posterior one longer than those anterior. Gill leaves discoid in shape, protected by long posterior papillae.	en	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): 265-310, DOI: 10.1080/00222933.2022.2040630, URL: http://dx.doi.org/10.1080/00222933.2022.2040630
024087ABD840D13B9ACE222CFCAFFCD2.taxon	biology_ecology	Ecology The singleton specimen was found on an unidentified bryozoan species of the genus Bugula. The species is nocturnal; during the day slugs are found ‘ resting’ at the base of bryozoans.	en	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): 265-310, DOI: 10.1080/00222933.2022.2040630, URL: http://dx.doi.org/10.1080/00222933.2022.2040630
024087ABD840D13B9ACE222CFCAFFCD2.taxon	distribution	Distribution Originally described from the North Sea (England; Montagu 1813); New South Wales, Australia (Burn 1978); south-west coast of India (Mohamed Hatha 2017); north-east American coast, Portugal and Italy (Gerovasileiou et al. 2017; Bariche et al. 2020); Spain: the Canary Islands, Cantabric Sea (Cervera et al. 2004), Catalonia (this study).	en	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): 265-310, DOI: 10.1080/00222933.2022.2040630, URL: http://dx.doi.org/10.1080/00222933.2022.2040630
024087ABD840D13B9ACE222CFCAFFCD2.taxon	discussion	Remarks This species has a broad distribution and is usually found in temperate waters (Dekker 1986). In the western Atlantic, T. pennigera has peaks of abundance during which, over the course of a few days, large numbers of specimens appear (Willan and Coleman 1984). Suborder CLADOBRANCHIA Family AEOLIDIIDAE Gray, 1827 Genus Anteaeolidiella M. C. Miller, 2001	en	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): 265-310, DOI: 10.1080/00222933.2022.2040630, URL: http://dx.doi.org/10.1080/00222933.2022.2040630
024087ABD841D13B9A5A244CFD52FC2A.taxon	description	(Figure 3 (e ))	en	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): 265-310, DOI: 10.1080/00222933.2022.2040630, URL: http://dx.doi.org/10.1080/00222933.2022.2040630
024087ABD842D1399AEF2585FF0FFE52.taxon	description	(Figure 3 (f ))	en	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): 265-310, DOI: 10.1080/00222933.2022.2040630, URL: http://dx.doi.org/10.1080/00222933.2022.2040630
024087ABD842D1399AEF2585FF0FFE52.taxon	materials_examined	Material examined Cala Maset caves, Sant Feliu de Guíxols (Spain), 41 ° 47 ʹ 10.5 ” N, 3 ° 2 ʹ 44.6 ” E, 13 April 2016, 0.3 m depth, 1 spc., L = 5 mm; 31 December 2017, 1.2 m depth, 3 spcs, juveniles and adults, L = 15 mm; 13 January 2018, 0.4 m depth, 2 spcs, L = 3 – 7 mm; 31 December 2017, 1.2 m depth, 3 spcs, juveniles and adults, L = 15 mm; Le Ponton, Étang de Thau, Sète (France), 43 ° 25 ʹ 28.5 ” N, 3 ° 42 ʹ E, 13 April 2018, 0.2 m depth, 4 spcs, adults, L = 7 – 10 mm; 21 May 2018, 0.2 m depth, 12 spcs, adults and egg masses, L = 7 – 10 mm; la Farge, Étang de Thau, Sète (France), 43 ° 25 ʹ 48 ” N, 3 ° 42 ʹ 14 ” E, 21 May 2018, 0.2 m depth, 17 spcs, adults and egg masses, L = 7 – 10 mm; Port de Sant Feliu (Spain), 41 ° 46 ʹ 42.2 ” N, 3 ° 02 ʹ 16.4 ” E, 29 January 2020, 0.2 m depth, 11 spcs, adults, juveniles and egg masses, L = 2 – 12 mm; Arenys de Mar port (Spain), 41 ° 34 ʹ 38.8 ” N, 2 ° 33 ʹ 23.5 ” E, 15 February 2020, 0.2 m depth, 2 spcs, adults, L = 10 mm; Port de Blanes (Spain), 41 ° 40 ʹ 25.5 ” N, 2 ° 47 ʹ 48.6 ” E, 2 March 2020, 0.2 m depth, 2 spcs, adults, L = 6 – 10 mm; Mar Menor, Cartagena (Spain), 37 ° 38 ʹ 6 ” N, 0 ° 44 ʹ 10.3 ” W, 27 September 2020, 0.3 m depth, 7 spcs, juveniles, adults and egg masses, L = 2 – 6 mm. External morphology Body elongate, narrow, background colour white with black marks all along but most concentrated in the head area. Rhinophores black with white tips. Cerata with tubercles, apical part black.	en	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): 265-310, DOI: 10.1080/00222933.2022.2040630, URL: http://dx.doi.org/10.1080/00222933.2022.2040630
024087ABD842D1399AEF2585FF0FFE52.taxon	biology_ecology	Ecology Specimens were found at shallow depths where there was an influx of fresh water, on rocks and hydrozoans, possibly Obelia spp., feeding and laying large, short, linear, white egg masses (very different from the characteristic egg masses of the genus Doto, with an ‘ S’ shape) at the bottom of the colony. Found to be more active at night.	en	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): 265-310, DOI: 10.1080/00222933.2022.2040630, URL: http://dx.doi.org/10.1080/00222933.2022.2040630
024087ABD842D1399AEF2585FF0FFE52.taxon	distribution	Distribution Corsica (Ortea and Bouchet 1989); Italy (Chiarore et al. 2019); Spain: Spanish Levantine coast (this study), Mallorca (GROC 2009 – 2021), Catalonia (this study); France (this study).	en	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): 265-310, DOI: 10.1080/00222933.2022.2040630, URL: http://dx.doi.org/10.1080/00222933.2022.2040630
024087ABD842D1399AEF2585FF0FFE52.taxon	discussion	Remarks This species is easily distinguished from Doto conspecifics by the presence of black rhinophores and small tubercles with a black dot in the cerata (Ortea and Bouchet 1989).	en	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): 265-310, DOI: 10.1080/00222933.2022.2040630, URL: http://dx.doi.org/10.1080/00222933.2022.2040630
024087ABD843D1399A8C2529FBBCFAEE.taxon	description	(Figure 3 (g ))	en	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): 265-310, DOI: 10.1080/00222933.2022.2040630, URL: http://dx.doi.org/10.1080/00222933.2022.2040630
024087ABD843D1399A8C2529FBBCFAEE.taxon	materials_examined	Material examined Punta del Romaní, L’Escala (Spain), 42 ° 6 ʹ 54 ” N, 3 ° 10 ʹ 9 ” E, 6 March 2021, 9 m depth, 1 spc., juvenile, L = 10 mm. External morphology Body elongate, cream to brown, with numerous white spots in oral veil. Rhinophoral sheath and back with numerous white spots in juveniles; rhinophoral sheath completely white in adults. Cerata beige to ochre, darker than body. Rhinophores homogeneously ochre.	en	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): 265-310, DOI: 10.1080/00222933.2022.2040630, URL: http://dx.doi.org/10.1080/00222933.2022.2040630
024087ABD843D1399A8C2529FBBCFAEE.taxon	biology_ecology	Ecology This species frequents cold waters, feeding on colonies of hydrozoans, especially of the genus Nemertesia Lamouroux, 1812, on which it lays egg masses in the form of a pink ribbon.	en	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): 265-310, DOI: 10.1080/00222933.2022.2040630, URL: http://dx.doi.org/10.1080/00222933.2022.2040630
024087ABD843D1399A8C2529FBBCFAEE.taxon	distribution	Distribution Widely recorded in the north-eastern Atlantic to the Galician coast (Ortea et al, 1978); Mediterranean Sea: Catalonian coast (this study).	en	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): 265-310, DOI: 10.1080/00222933.2022.2040630, URL: http://dx.doi.org/10.1080/00222933.2022.2040630
024087ABD843D1399A8C2529FBBCFAEE.taxon	discussion	Remarks Often found feeding on Nemertesia antenninna (Linnaeus, 1758). This is the first record in the Mediterranean Sea, wherein it was observed inside a cave feeding on Kirchenpaueria pinnata (Linnaeus, 1758); after two weeks the specimen and its prey were not found anymore.	en	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): 265-310, DOI: 10.1080/00222933.2022.2040630, URL: http://dx.doi.org/10.1080/00222933.2022.2040630
024087ABD843D1279A8C229EFCB4FC53.taxon	description	(Figure 3 (h ))	en	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): 265-310, DOI: 10.1080/00222933.2022.2040630, URL: http://dx.doi.org/10.1080/00222933.2022.2040630
024087ABD843D1279A8C229EFCB4FC53.taxon	materials_examined	Material examined Cala d’Aiguablava, Begur (Spain), 41 ° 56 ʹ 13.4 ” N, 3 ° 13 ʹ 08.6 ” E, 22 June 2018, 0 m depth, 6 spcs, juveniles and adults, L = 2 – 5 mm; Cala Maset caves, Sant Feliu de Guíxols (Spain), 41 ° 47 ʹ 10.5 ” N, 3 ° 2 ʹ 44.6 ” E, 11 February 2020, 0.1 m depth, 7 spcs, adults and egg masses, L = 5 – 10 mm. External morphology Body elongate, narrow, background colour white with black patches to completely black. Rhinophores elongate, transluscent white. Cerata displayed in a sinuous ‘ S’ fashion with white tubercles only on the external part, the inner part being almost smooth.	en	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): 265-310, DOI: 10.1080/00222933.2022.2040630, URL: http://dx.doi.org/10.1080/00222933.2022.2040630
024087ABD843D1279A8C229EFCB4FC53.taxon	biology_ecology	Ecology Specimens found on floating debris. The specimens from Aiguablava were living on plastic debris eating hydrozoan colonies, probably of the genus Obelia. The specimens of Cala Maset were living on floating wood. Slugs mated and laid egg masses while eating hydrozoans of the genus Tubularia. Egg masses are shaped like a winding cord forming an ‘ S’; egg colour is yellowish.	en	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): 265-310, DOI: 10.1080/00222933.2022.2040630, URL: http://dx.doi.org/10.1080/00222933.2022.2040630
024087ABD843D1279A8C229EFCB4FC53.taxon	distribution	Distribution Italy (Schmekel and Portmann 1982); Spain: Canary Islands (Cervera et al. 2004), Spanish Levantine coast (Cervera et al. 2004), Catalonia (this study).	en	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): 265-310, DOI: 10.1080/00222933.2022.2040630, URL: http://dx.doi.org/10.1080/00222933.2022.2040630
024087ABD843D1279A8C229EFCB4FC53.taxon	discussion	Remarks This species can be differentiated from other Doto species by having a black body with very elongated rhinophores, a smooth edge on the rhinophoral sheath, and ‘ S’ - shaped cerata, the inner part being almost smooth and the external with tubercles aligned longitudinally (Ortea et al. 1997). Family PHYLLIROEIDAE Genus Phylliroe Péron and Lesueur, 1810	en	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): 265-310, DOI: 10.1080/00222933.2022.2040630, URL: http://dx.doi.org/10.1080/00222933.2022.2040630
024087ABD85DD124996E24FDFCDBFDCB.taxon	description	(Figure 4 (a ))	en	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): 265-310, DOI: 10.1080/00222933.2022.2040630, URL: http://dx.doi.org/10.1080/00222933.2022.2040630
024087ABD85DD124996E24FDFCDBFDCB.taxon	materials_examined	Material examined Cala d’Aiguablava, Begur (Spain), 41 ° 56 ʹ 13.4 ” N, 3 ° 13 ʹ 8.6 ” E, 29 March 2021, 3 m depth, 1 spc., adult, L = 20 mm; Cap de Begur, Begur (Spain), 41 ° 57 ʹ 2 ” N, 3 ° 14 ʹ 3.1 ” E, 30 March 2021, 2 – 4 m depth, 4 spcs, adults, L = 20 – 30 mm; Cala Sa Tuna, Begur (Spain), 41 ° 57 ʹ 38 ” N, 3 ° 13 ʹ 52 ” E, 31 March 2021, 1 m depth, 5 spcs, adults, L = 10 – 20 mm; Montiel, Tamariu (Spain), 41 ° 54 ʹ 55.9 ” N, 3 ° 12 ʹ 46.3 ” E, 1 April 2021, 3 m depth, 2 spcs, adults, L = 20 mm. External morphology Body flat, laterally compressed, ending in a fishtail shape; translucent tegument, internal organs seen by transparency (four digestive gland ramifications, reproductive and nervous systems); numerous yellow, iridescent spots on dorsal and ventral sides. Rhinophores long, smooth, slightly rippled once in ethanol.	en	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): 265-310, DOI: 10.1080/00222933.2022.2040630, URL: http://dx.doi.org/10.1080/00222933.2022.2040630
024087ABD85DD124996E24FDFCDBFDCB.taxon	biology_ecology	Ecology The species lives in the open sea, generally at great depths, having a body adapted for swimming. Feeds on jellyfish, although its diet is not well studied.	en	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): 265-310, DOI: 10.1080/00222933.2022.2040630, URL: http://dx.doi.org/10.1080/00222933.2022.2040630
024087ABD85DD124996E24FDFCDBFDCB.taxon	distribution	Distribution Syria (Durgham and Ikhtiyar 2020); Italy (Schmekel and Portmann 1982); Spain: Canary Islands (Cervera et al. 2004), Spanish Levantine coast (Cervera et al. 2004), Catalonia (this study).	en	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): 265-310, DOI: 10.1080/00222933.2022.2040630, URL: http://dx.doi.org/10.1080/00222933.2022.2040630
024087ABD85DD124996E24FDFCDBFDCB.taxon	discussion	Remarks According to Lamarck’s description (1816) and his illustrations, our specimens resemble P. bucephala, but a molecular analysis is required to validate its identity due to its similarities to P. lichtensteinii Eschscholtz, 1825, which has also been recorded in the Mediterranean Sea. In any case, this represents the first record of the genus Phylliroe on the Iberian Spanish coast. Family EUBRANCHIDAE Odhner, 1934 Genus Amphorina Quatrefages, 1844	en	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): 265-310, DOI: 10.1080/00222933.2022.2040630, URL: http://dx.doi.org/10.1080/00222933.2022.2040630
024087ABD85ED1259BAE2559FE59FDCF.taxon	description	Martynov, 2020 (Figure 4 (b ))	en	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): 265-310, DOI: 10.1080/00222933.2022.2040630, URL: http://dx.doi.org/10.1080/00222933.2022.2040630
024087ABD85ED1259BAE2559FE59FDCF.taxon	materials_examined	Material examined Cala d’Aiguafreda, Begur (Spain), 41 ° 57 ʹ 49 ” N, 3 ° 13 ʹ 41 ” E, 22 June 2013, 18 m depth, 1 spc., juvenile, L = 3 mm (GROC 2009 _ 2021); Balaruc-les-Bains (France), 43 ° 26 ʹ 28.8 ” N, 3 ° 41 ʹ 3 ” E, 5 April 2014, 2 m depth, 2 spcs, adults, L = 10 – 15 mm; Barra de l’Arbre, Mataró (Spain), 41 ° 31 ʹ 57.9 ” N, 2 ° 28 ʹ 21.2 ” E, 1 May 2014, 20 m depth, 1 spc., juvenile, H = 2 mm; Punta del Romaní, L’Escala (Spain), 42 ° 6 ʹ 54 ” N, 3 ° 10 ʹ 9 ” E, 12 April 2015, 4 m depth, 3 spcs, adults, L = 10 – 12 mm; Cala Maset caves, Sant Feliu de Guíxols (Spain), 41 ° 47 ʹ 10 ” N, 3 ° 2 ʹ 44 ” E, 16 January 2018, 1 m depth, 2 spcs, adults, L = 10 mm; 16 January 2018, 1 m depth, 2 spcs, adults and egg masses, L = 10 – 12 mm; 22 January 2018, 0.7 m depth, 6 spcs, adults, mating and egg masses, L = 12 – 15 mm; 16 February 2018, 1.2 m depth, 2 spcs, adults, L = 8 – 10 mm; 9 March 2018, 0.6 m depth, 6 spcs, adults, mating and egg masses, L = 10 – 15 mm; Punta d’en Bosch, Sant Feliu de Guíxols (Spain), 41 ° 45 ʹ 54 ” N, 3 ° 0 ʹ 11 ” E, 17 April 2018, 1 m depth, 5 spcs, adults mating, L = 8 – 12 mm; Cova de l’infern (Spain), 42 ° 19 ʹ 2.75 ” N, 3 ° 19 ʹ 12.74 ” E, 2 March 2019, 1 m depth, 3 spcs, adults and egg masses, L = 10 – 20 mm.	en	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): 265-310, DOI: 10.1080/00222933.2022.2040630, URL: http://dx.doi.org/10.1080/00222933.2022.2040630
024087ABD85ED1259BAE2559FE59FDCF.taxon	description	External morphology Body elongate, narrow, background colour variable, typically white with black and orange marks, some specimens with completely white or orange colouration. Rhinophores and oral tentacles smooth and yellow, white apically. Cerata globular, with white and black marks, apical part yellow.	en	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): 265-310, DOI: 10.1080/00222933.2022.2040630, URL: http://dx.doi.org/10.1080/00222933.2022.2040630
024087ABD85ED1259BAE2559FE59FDCF.taxon	biology_ecology	Ecology Specimens found at a broad range of depths, always associated with hydrozoan colonies. The specimens of Sant Feliu were found inside a cave and associated with hydrozoans of the genus Sertularella, on which they often lay their egg masses. Active at night, mating and laying eggs. During the day they are found at the base of the hydrozoans. The egg mass is spiral-shaped, usually laid on rocks, but also on the hydrozoans upon which they feed.	en	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): 265-310, DOI: 10.1080/00222933.2022.2040630, URL: http://dx.doi.org/10.1080/00222933.2022.2040630
024087ABD85ED1259BAE2559FE59FDCF.taxon	distribution	Distribution Italy and Croatia (Korshunova et al. 2020); France (this study); Spain: Catalonia (this study).	en	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): 265-310, DOI: 10.1080/00222933.2022.2040630, URL: http://dx.doi.org/10.1080/00222933.2022.2040630
024087ABD85ED1259BAE2559FE59FDCF.taxon	discussion	Remarks This species was recently described, but up to now it was considered a morphotype of Eubranchus farrani, now Amphorina farrani (Alder and Hancock 1845). Amphorina andra is variable in body colour, from completely white or orange to a white with black spots and orange circles on the dorsum. Specimens found at deeper depths were typically small, whereas specimens found at very shallow depths, mostly in caves, were larger and found on hydrozoan colonies of the genera Obelia and Sertularella, among others. Populations observed in Croatia were in shallow waters, between 0 and 0.5 m (Korshunova et al. 2020), as was the population studied in Sant Feliu, Catalonia (Spain).	en	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): 265-310, DOI: 10.1080/00222933.2022.2040630, URL: http://dx.doi.org/10.1080/00222933.2022.2040630
024087ABD85FD1229AFA2596FCE2FE2C.taxon	description	(Figure 4 (c ))	en	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): 265-310, DOI: 10.1080/00222933.2022.2040630, URL: http://dx.doi.org/10.1080/00222933.2022.2040630
024087ABD85FD1229AFA2596FCE2FE2C.taxon	materials_examined	Material examined Cala Maset caves, Sant Feliu de Guíxols (Spain), 41 ° 47 ʹ 10 ” N, 3 ° 2 ʹ 44 ” E, 11 to 16 February 2018, 1.5 – 2 m depth, 13 spcs, adults and egg masses, L = 4 – 7 mm; 9 to 15 March 2018, 1.5 m depth, 13 spcs, juveniles, adults and egg masses, L = 6 – 10 mm; 30 March 2018, 1.5 m depth, 7 spcs, juveniles, adults and egg masses, L = 7 – 15 mm; 15 April 2018, 1.5 m depth, 2 spcs, adults, L = 8 mm; 7 May 2018, 0.7 m depth, 2 spcs, adults, L = 7 mm. External morphology Body elongate, narrow, with a black mark on the dorsum (corresponding to digestive gland seen by transparency), starting between the first couple of cerata and ending at the last group of cerata. Background colour beige with brown and white punctuation. Rhinophores long, equal. Cerata large and fusiform compressed at the middle, transparent with white to dark brown visible digestive gland, white tips.	en	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): 265-310, DOI: 10.1080/00222933.2022.2040630, URL: http://dx.doi.org/10.1080/00222933.2022.2040630
024087ABD85FD1229AFA2596FCE2FE2C.taxon	biology_ecology	Ecology Specimens found during the day at the base of the hydrozoan Kirchenpaueria halecioides (Alder, 1859), but actively crawling, mating and feeding on the colony at night. ‘ C’ - shaped egg masses were found on the hydrozoan.	en	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): 265-310, DOI: 10.1080/00222933.2022.2040630, URL: http://dx.doi.org/10.1080/00222933.2022.2040630
024087ABD85FD1229AFA2596FCE2FE2C.taxon	distribution	Distribution Ghana; Strait of Gibraltar (García-Gómez 1987); France (Rudman 2020); Atlantic Spanish coast: Cantabria (Ortea and Bacallado 1981); Mediterranean Spanish coast: Catalonia (this study).	en	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): 265-310, DOI: 10.1080/00222933.2022.2040630, URL: http://dx.doi.org/10.1080/00222933.2022.2040630
024087ABD85FD1229AFA2596FCE2FE2C.taxon	discussion	Remarks When active, the cerata are completely lateralised. Slugs are camouflaged from the pycnogonids also found on the hydrozoan colonies (X. Salvador pers. obs.). Specimens can be differentiated externally from other Eubranchus species by the insertion of the first cerata groupings and the visible black digestive gland on the dorsum between cerata (Llera and Ortea 1981). Family FACELINIDAE Bergh, 1889 Genus Godiva Macnae, 1954	en	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): 265-310, DOI: 10.1080/00222933.2022.2040630, URL: http://dx.doi.org/10.1080/00222933.2022.2040630
024087ABD858D1229ADE26C2FCB1F957.taxon	description	(Figure 4 (d ))	en	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): 265-310, DOI: 10.1080/00222933.2022.2040630, URL: http://dx.doi.org/10.1080/00222933.2022.2040630
024087ABD858D1229ADE26C2FCB1F957.taxon	materials_examined	Material examined Cala Maset caves, Sant Feliu de Guíxols (Spain), 41 ° 47 ʹ 10.5 ” N, 3 ° 2 ʹ 44.6 ” E, 31 December 2017, 2 m depth, 1 spc., L = 10 mm; 5 January 2018, 1.3 m depth, 1 spc., adult, L = 25 mm; 22 January 2018, 1.3 m depth, 1 spc., adult, L = 25 mm; 29 January 2018, 1.3 m depth, 1 spc., adult, L = 25 mm; Le Ponton, Étang de Thau, Sète (France), 43 ° 25 ʹ 28.5 ” N, 3 ° 42 ʹ E, 8 April 2017, 1 m depth, 5 spc., adults and egg masses, L = 20 – 40 mm; 20 May 2018, 1 m depth, 4 spc., juveniles, adults and egg masses, L = 5 – 30 mm. External morphology Body elongate, narrow, background colour light orange with whitish-blue electric marks. Oral tentacles present a whitish blue line connecting apical part with base of rhinophores. Rhinophores conical, slightly annulated, whitish-yellow apically. Cerata abundant, smooth, base red, tops orange, blue and yellow.	en	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): 265-310, DOI: 10.1080/00222933.2022.2040630, URL: http://dx.doi.org/10.1080/00222933.2022.2040630
024087ABD858D1229ADE26C2FCB1F957.taxon	biology_ecology	Ecology This species has a very broad diet (Betti et al. 2015), and is commonly found eating anemones (e. g. the genera Anemonia and Aiptasia), worms (e. g. Sabella), and other heterobranchs such as Spurilla neapolitana (Delle Chiaje, 1841).	en	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): 265-310, DOI: 10.1080/00222933.2022.2040630, URL: http://dx.doi.org/10.1080/00222933.2022.2040630
024087ABD858D1229ADE26C2FCB1F957.taxon	distribution	Distribution This is an invasive species originally from South Africa and the Pacific Sea [e. g. Australia (Nimbs and Smith 2017), Hawaii (Gosliner 1980), now found in Italy, France, the Mediterranean Spanish coast: Andalucía (Zenetos et al. 2016; Gerovasileiou et al. 2017) and Catalonia (this study).	en	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): 265-310, DOI: 10.1080/00222933.2022.2040630, URL: http://dx.doi.org/10.1080/00222933.2022.2040630
024087ABD858D1229ADE26C2FCB1F957.taxon	discussion	Remarks This species is a large facelinid with a very characteristic colour pattern, making it difficult to misidentify. In the Étang de Thau, France, the species is very abundant during spring.] Family PISEINOTECIDAE Edmunds, 1970 Genus Piseinotecus Er. Marcus, 1955	en	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): 265-310, DOI: 10.1080/00222933.2022.2040630, URL: http://dx.doi.org/10.1080/00222933.2022.2040630
024087ABD859D1239B8C27ADFC14FBAE.taxon	description	(Figure 4 (e ))	en	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): 265-310, DOI: 10.1080/00222933.2022.2040630, URL: http://dx.doi.org/10.1080/00222933.2022.2040630
024087ABD859D1239B8C27ADFC14FBAE.taxon	materials_examined	Material examined Cala Maset caves, Sant Feliu de Guíxols (Spain), 41 ° 47 ʹ 10 ” N, 3 ° 2 ʹ 44 ” E, 22 January 2018, 1.8 m depth, 7 spcs, juveniles, adults and egg masses, L = 4 – 25 mm; 29 January 2018, 1.6 m depth, 9 spcs, adults and egg masses, L = 12 – 25 mm. External morphology Body elongate, narrow, background colour violet or pink. Rhinophores and oral tentacles smooth, white apically with degraded white punctuation. Cerata smooth, long, translucent, with digestive gland visible in orange; white apically, presenting profuse white punctuation.	en	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): 265-310, DOI: 10.1080/00222933.2022.2040630, URL: http://dx.doi.org/10.1080/00222933.2022.2040630
024087ABD859D1239B8C27ADFC14FBAE.taxon	biology_ecology	Ecology Specimens found mating and laying the egg masses on unidentified species of hydrozoans at night, and inactive at the base of the colonies during the day.	en	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): 265-310, DOI: 10.1080/00222933.2022.2040630, URL: http://dx.doi.org/10.1080/00222933.2022.2040630
024087ABD859D1239B8C27ADFC14FBAE.taxon	distribution	Distribution Morocco (Tamsouri et al. 2014); Italy (Ballesteros et al. 2012 – 2021), Catalonia (Ballesteros et al. 2016; this study).	en	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): 265-310, DOI: 10.1080/00222933.2022.2040630, URL: http://dx.doi.org/10.1080/00222933.2022.2040630
024087ABD859D1239B8C27ADFC14FBAE.taxon	discussion	Remarks Originally described from Morocco, it is quite widespread on the Catalan coast. Differs from similar-looking species, such as Edmundsella pedata (Montagu, 1816), by the presence of abundant white spots in the cerata, rhinophores and oral tentacles.	en	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): 265-310, DOI: 10.1080/00222933.2022.2040630, URL: http://dx.doi.org/10.1080/00222933.2022.2040630
024087ABD859D1209AEC235FFCF9FD94.taxon	description	(Figure 4 (f ))	en	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): 265-310, DOI: 10.1080/00222933.2022.2040630, URL: http://dx.doi.org/10.1080/00222933.2022.2040630
024087ABD859D1209AEC235FFCF9FD94.taxon	materials_examined	Material examined Punta del Romaní, l’Escala, Girona (Catalunya), 42 ° 6 ʹ 53.088 ” N, 3 ° 10 ʹ 6.765 ” E, 8 November 2014, 1 spc.; Le Ponton, Étang de Thau, Sète (France), 43 ° 25 ʹ 28.5 ” N, 3 ° 42 ʹ E, 20 May 2018, 0.4 m depth, 1 spc., adult, L = 13 mm. External morphology Body elongate, narrow, background colour transparent white. Rhinophores and oral tentacles smooth, translucent with white spots. Cerata smooth, background colour white or beige, base with a green iridescent sphere at their base; first and second row of cerata connected with a dark line.	en	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): 265-310, DOI: 10.1080/00222933.2022.2040630, URL: http://dx.doi.org/10.1080/00222933.2022.2040630
024087ABD859D1209AEC235FFCF9FD94.taxon	biology_ecology	Ecology The singleton specimen was found on the hydrozoan Obelia sp. at night. Distribution Ghana (Edmunds 1977); Portugal (Cervera et al. 2004); Italy and Adriatic Sea (Zenetos et al. 2016); Spain: Canary Islands (Ortea et al. 2003), Catalonia (GROC 2009 – 2021; Ballesteros et al. 2016); France (this study).	en	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): 265-310, DOI: 10.1080/00222933.2022.2040630, URL: http://dx.doi.org/10.1080/00222933.2022.2040630
024087ABD859D1209AEC235FFCF9FD94.taxon	discussion	Remarks This elusive species is easily diagnosed by an iridescent green sphere at the base of the cerata (Ortea et al. 2003). Family TRINCHESIIDAE F. Nordsieck, 1972 Genus Tenellia A. Costa, 1866	en	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): 265-310, DOI: 10.1080/00222933.2022.2040630, URL: http://dx.doi.org/10.1080/00222933.2022.2040630
024087ABD85AD1209ADB2503FCE4F9A4.taxon	description	(Figure 4 (g ))	en	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): 265-310, DOI: 10.1080/00222933.2022.2040630, URL: http://dx.doi.org/10.1080/00222933.2022.2040630
024087ABD85AD1209ADB2503FCE4F9A4.taxon	materials_examined	Material examined Port de Blanes (Spain), 41 ° 40 ʹ 25.5 ” N, 2 ° 47 ʹ 48.6 ” E, 21 January 2019, 0.1 m depth, 1 spc., adults, L = 7 mm. External morphology Body elongate, narrow, background colour black. Rhinophores smooth; oral veil very well developed and without oral tentacles. Cerata lateral, elongated; tip swollen.	en	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): 265-310, DOI: 10.1080/00222933.2022.2040630, URL: http://dx.doi.org/10.1080/00222933.2022.2040630
024087ABD85AD1209ADB2503FCE4F9A4.taxon	biology_ecology	Ecology A single specimen was found in a mass of hydrozoans in a floating dock with other sea slugs.	en	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): 265-310, DOI: 10.1080/00222933.2022.2040630, URL: http://dx.doi.org/10.1080/00222933.2022.2040630
024087ABD85AD1209ADB2503FCE4F9A4.taxon	distribution	Distribution North-east Atlantic (OBIS 2021); Pacific North American coast (iNaturalist. org 2021; OBIS 2021); Portugal (Encarnação et al. 2020); Spain: Canary Islands, Atlantic Andalusian coast, Galicia, Levantine coast (Cervera et al. 2004), Catalonia (this study).	en	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): 265-310, DOI: 10.1080/00222933.2022.2040630, URL: http://dx.doi.org/10.1080/00222933.2022.2040630
024087ABD85AD1209ADB2503FCE4F9A4.taxon	discussion	Remarks This species has a widespread and cosmopolitan distribution (Roginskaya 1970), being found in oceanic and brackish waters (Thompson and Brown 1984). Tenellia adspersa can be differentiated from conspecifics by having an oral veil connecting the oral tentacles and the cerata are clustered (Evertsen et al. 2004). Typically, the colour of the body and cerata varies from black to creamy with their diet (authors pers. obs.). Encarnação et al. (2020) found this species associated with the invasive hydrozoan Cordylophora caspia (Pallas, 1771) on artificial structures. Genus Trinchesia Er. Ihering, 1879	en	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): 265-310, DOI: 10.1080/00222933.2022.2040630, URL: http://dx.doi.org/10.1080/00222933.2022.2040630
024087ABD85AD1219BD72173FB92FAAA.taxon	description	Fletcher, Malmberg, Lundin and Martynov, 2019 (Figure 4 (h ))	en	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): 265-310, DOI: 10.1080/00222933.2022.2040630, URL: http://dx.doi.org/10.1080/00222933.2022.2040630
024087ABD85AD1219BD72173FB92FAAA.taxon	materials_examined	Material examined Punta del Romaní, L’Escala (Spain), 42 ° 6 ʹ 54 ” N, 3 ° 10 ʹ 9 ” E, 10 February 2014, 7 m depth, 1 spc., juvenile, L = 3 mm; 14 February 2015, 14 m depth, 1 spc., adult, L = 10 mm; Le Ponton, Étang de Thau, Sète (France), 43 ° 25 ʹ 28.5 ” N, 3 ° 42 ʹ E, 14 April 2018, 1 m depth, 3 spc., adults, L = 7 – 20 mm; Cala Maset caves, Sant Feliu de Guíxols (Spain), 41 ° 47 ʹ 10 ” N, 3 ° 2 ʹ 44 ” E, 15 April 2018, 0.6 m depth, 15 spcs, juveniles, adults and egg masses, L = 4 – 15 mm; 6 June 2018, 0.6 m depth, 20 spcs, adults and egg masses, L = 10 – 15 mm; 11 March 2020, 0.5 m depth, 12 spcs, adults and mating, L = 7 – 15 mm; Tamariu beach (Spain), 41 ° 55 ʹ 0.5 ” N, 3 ° 12 ʹ 27.1 ” E, 11 February 2019, 2 m depth, 4 spcs, adults, L = 6 – 10 mm.	en	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): 265-310, DOI: 10.1080/00222933.2022.2040630, URL: http://dx.doi.org/10.1080/00222933.2022.2040630
024087ABD85AD1219BD72173FB92FAAA.taxon	description	External morphology Body elongate, narrow, background colour white or light yellow. Rhinophores and oral tentacles smooth, more intensely white than the body. Red or orange mark between eyes and on central dorsum. Cerata globular, displaying a bright yellow-blue-yellow colouration.	en	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): 265-310, DOI: 10.1080/00222933.2022.2040630, URL: http://dx.doi.org/10.1080/00222933.2022.2040630
024087ABD85AD1219BD72173FB92FAAA.taxon	biology_ecology	Ecology Specimens found mating and laying the eggs on the hydrozoans Sertularella mediterranea Hartlaub, 1901 and Sertularella polyzonias (Linnaeus, 1758) inside superficial caves.	en	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): 265-310, DOI: 10.1080/00222933.2022.2040630, URL: http://dx.doi.org/10.1080/00222933.2022.2040630
024087ABD85AD1219BD72173FB92FAAA.taxon	distribution	Distribution North-east Atlantic (Korshunova et al. 2019); Adriatic Sea (Ballesteros et al. 2012 – 2021); Mediterranean French coast (this study); Spain: Catalonia (this study).	en	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): 265-310, DOI: 10.1080/00222933.2022.2040630, URL: http://dx.doi.org/10.1080/00222933.2022.2040630
024087ABD85AD1219BD72173FB92FAAA.taxon	discussion	Remarks This species was recently described and observed in the North Atlantic and Mediterranean Sea (Korshunova et al. 2019). It is different from similar Trinchesia species by having one light or pale red marking between the eyes and in the middle part of the back. This species likely has a shorter life cycle than T. morrowae (Korshunova et al. 2019), since it has only been observed in the winter and spring months, whereas T. morrowae is observed yearround. Trinchesia caerulea (Montagu, 1804) has been found only during spring and autumn and is usually found in deeper waters than T. cuanensis (X. Salvador pers. obs.).	en	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): 265-310, DOI: 10.1080/00222933.2022.2040630, URL: http://dx.doi.org/10.1080/00222933.2022.2040630
024087ABD85BD12F9A8F2123FCE6FB72.taxon	description	(Figure 5 (a ))	en	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): 265-310, DOI: 10.1080/00222933.2022.2040630, URL: http://dx.doi.org/10.1080/00222933.2022.2040630
024087ABD85BD12F9A8F2123FCE6FB72.taxon	materials_examined	Material examined Ullastres 3, Llafranc (Spain), 41 ° 53 ʹ 14.1 ” N, 3 ° 12 ʹ 26.0 ” E, 27 February 2019, 0.5 m depth, 3 spcs, adults, L = 10 mm; Cala Sa Tuna, Begur (Spain), 41 ° 57 ʹ 38 ” N, 3 ° 13 ʹ 52 ” E, 9 March 2019, 0.8 m depth, 1 spc., adult, L = 10 mm; Montiel, Tamariu (Spain), 41 ° 54 ʹ 55.9 ” N, 3 ° 12 ʹ 46.3 ” E, 13 March 2019, 1 m depth, 20 spcs, adults, L = 5 – 10 mm. External morphology Shell narrow, elongated, conical, back end slightly curved, smooth. Parapodia transparent, large, with double-axe shape.	en	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): 265-310, DOI: 10.1080/00222933.2022.2040630, URL: http://dx.doi.org/10.1080/00222933.2022.2040630
024087ABD85BD12F9A8F2123FCE6FB72.taxon	biology_ecology	Ecology Found in open waters close to the surface and around other pelagic pteropod and salp species.	en	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): 265-310, DOI: 10.1080/00222933.2022.2040630, URL: http://dx.doi.org/10.1080/00222933.2022.2040630
024087ABD85BD12F9A8F2123FCE6FB72.taxon	distribution	Distribution Cosmopolitan. In the Mediterranean Sea this species has been reported from the eastern and western Mediterranean, and in the Malta stretch and between Mallorca and Sicily (OBIS 2021). This is the first report of this species from the Mediterranean Spanish coast.	en	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): 265-310, DOI: 10.1080/00222933.2022.2040630, URL: http://dx.doi.org/10.1080/00222933.2022.2040630
024087ABD85BD12F9A8F2123FCE6FB72.taxon	discussion	Remarks Almost all records in the Mediterranean are based on shell observations or from specimens caught in plankton tows in open waters, at superficial (0 – 10 m) or greater depths (600 – 700 m; OBIS 2021). Our specimens were found from February to March along with the massive arrival of pelagic zooplankton in superficial waters. This species is very similar to C. conica Eschscholtz, 1829, so several specimens with slightly different morphologies have been collected to determine whether both species could be present. In the case of both species, this record represents the first observation of either taxon for the Catalan coast. Genus Hyalocylis Fol, 1875	en	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): 265-310, DOI: 10.1080/00222933.2022.2040630, URL: http://dx.doi.org/10.1080/00222933.2022.2040630
024087ABD855D12C9ABF222CFCF2FC84.taxon	description	(Figure 5 (b ))	en	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): 265-310, DOI: 10.1080/00222933.2022.2040630, URL: http://dx.doi.org/10.1080/00222933.2022.2040630
024087ABD855D12C9ABF222CFCF2FC84.taxon	materials_examined	Material examined Cala Sa Tuna, Begur (Spain), 41 ° 57 ʹ 38 ” N, 3 ° 13 ʹ 52 ” E, 9 February 2019, 1 m depth, 1 spc., adult, L = 6 mm; Montiel, Tamariu (Spain), 41 ° 54 ʹ 55.9 ” N, 3 ° 12 ʹ 46.3 ” E, 13 March 2019, 1 m depth, 4 spcs, adults, L = 6 – 10 mm; 14 March 2019, 1 m depth, 3 spcs, adults, L = 6 – 10 mm. External morphology Shell wide, short, striated, conical, translucent. Parapodia large, transparent. Statocysts visible between shell and parapodia.	en	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): 265-310, DOI: 10.1080/00222933.2022.2040630, URL: http://dx.doi.org/10.1080/00222933.2022.2040630
024087ABD855D12C9ABF222CFCF2FC84.taxon	biology_ecology	Ecology Found in open waters close to the surface and around other pelagic pteropod and salp species.	en	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): 265-310, DOI: 10.1080/00222933.2022.2040630, URL: http://dx.doi.org/10.1080/00222933.2022.2040630
024087ABD855D12C9ABF222CFCF2FC84.taxon	distribution	Distribution Cosmopolitan. In the Mediterranean Sea, it is commonly reported in the eastern part (Koukouras 2010; OBIS 2021) and from the Italian coast (OBIS 2021). This species was recorded in Spanish Mediterranean waters by the study of Cervera et al. (2004) but only in remote areas tens of miles from the coast. This is the first report in the vicinity of the Mediterranean Spanish coast and the first record for Catalonia.	en	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): 265-310, DOI: 10.1080/00222933.2022.2040630, URL: http://dx.doi.org/10.1080/00222933.2022.2040630
024087ABD855D12C9ABF222CFCF2FC84.taxon	discussion	Remarks As for C. virgula, almost all records in the Mediterranean Sea are based on shells of specimens caught with plankton nets in open waters and at great depths (OBIS 2021). Our specimens were found from February to March along with the massive arrival of pelagic zooplankton. Family PERACLIDAE Tesch, 1913 Genus Peracle Forbes, 1844	en	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): 265-310, DOI: 10.1080/00222933.2022.2040630, URL: http://dx.doi.org/10.1080/00222933.2022.2040630
024087ABD856D12D9ADF2417FC8CFF4D.taxon	description	(Figure 5 (c ))	en	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): 265-310, DOI: 10.1080/00222933.2022.2040630, URL: http://dx.doi.org/10.1080/00222933.2022.2040630
024087ABD856D12D9ADF2417FC8CFF4D.taxon	materials_examined	Material examined Cala Sa Tuna, Begur, NE Spain, 41 ° 57 ʹ 38 ” N, 3 ° 13 ʹ 52 ” E, 31 March 2021, 1 m depth, 2 spcs, adults, L = 4 mm; 2 April 2021, 3 m depth, 1 spc., L = 4 mm. External morphology Shell helicoidal, conical, with reticulated microsculpture, orange due to digestive gland seen by transparency. Wing flaps broad, extending over the length of the shell.	en	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): 265-310, DOI: 10.1080/00222933.2022.2040630, URL: http://dx.doi.org/10.1080/00222933.2022.2040630
024087ABD856D12D9ADF2417FC8CFF4D.taxon	biology_ecology	Ecology This is a pelagic species living in offshore waters and its life cycle has not been well studied.	en	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): 265-310, DOI: 10.1080/00222933.2022.2040630, URL: http://dx.doi.org/10.1080/00222933.2022.2040630
024087ABD856D12D9ADF2417FC8CFF4D.taxon	distribution	Distribution Cosmopolitan; widely recorded in the Atlantic Ocean (OBIS 2021). Portugal, Canary Islands, Strait of Gibraltar (Cervera et al. 2004); the Mediterranean Sea from the Andalusian coast (Cervera et al. 2004), Italy (OBIS 2021), Greece (GBIF. org 2021) and Catalonia (this study).	en	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): 265-310, DOI: 10.1080/00222933.2022.2040630, URL: http://dx.doi.org/10.1080/00222933.2022.2040630
024087ABD856D12D9ADF2417FC8CFF4D.taxon	discussion	Remarks Easily identified by its morphology, but since it is a cosmopolitan and scarcely studied species, of which often only the shell is found, several specimens were collected for sequencing. Family PNEUMODERMATIDAE Latreille, 1825 Genus Pneumodermopsis Keferstein, 1862	en	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): 265-310, DOI: 10.1080/00222933.2022.2040630, URL: http://dx.doi.org/10.1080/00222933.2022.2040630
024087ABD857D12D9A0427D6FC57FB6B.taxon	description	(Figure 5 (d ))	en	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): 265-310, DOI: 10.1080/00222933.2022.2040630, URL: http://dx.doi.org/10.1080/00222933.2022.2040630
024087ABD857D12D9A0427D6FC57FB6B.taxon	materials_examined	Material examined Montiel, Tamariu (Spain), 41 ° 54 ʹ 55.9 ” N, 3 ° 12 ʹ 46.3 ” E, 13 February 2019, 1 m depth, 9 spcs, adults, L = 7 – 10 mm; Montiel, Tamariu (Spain), 41 ° 54 ʹ 55.9 ” N, 3 ° 12 ʹ 46.3 ” E, 12 March 2021, 3 m depth, 1 spc., adult, L = 5 mm; Cala Sa Tuna, 41 ° 57 ʹ 38 ” N, 3 ° 13 ʹ 52 ” E, 31 March 2021, 1 m depth, 2 spcs, juvenile and adult, L = 2 – 10 mm. External morphology Body rounded, transparent, with numerous glands, dark chromatophores can be seen by transparency all over body. Lateral gill extremely long, posterior gill absent. Posterior end with two ciliated bands. Head with two apical tentacles.	en	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): 265-310, DOI: 10.1080/00222933.2022.2040630, URL: http://dx.doi.org/10.1080/00222933.2022.2040630
024087ABD857D12D9A0427D6FC57FB6B.taxon	biology_ecology	Ecology Found in open waters close to the surface and with other pteropods and pelagic salps.	en	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): 265-310, DOI: 10.1080/00222933.2022.2040630, URL: http://dx.doi.org/10.1080/00222933.2022.2040630
024087ABD857D12D9A0427D6FC57FB6B.taxon	distribution	Distribution North Atlantic (OBIS 2021); Mediterranean Sea (Pruvot-Fol 1924); this is the first report of this gastropod from the Catalan coast (Spain).	en	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): 265-310, DOI: 10.1080/00222933.2022.2040630, URL: http://dx.doi.org/10.1080/00222933.2022.2040630
024087ABD857D12D9A0427D6FC57FB6B.taxon	discussion	Remarks Mostly found in North Atlantic waters (Pruvot-Fol 1924). Of the eight specimens collected and housed alive in the same container, two disappeared along with some other species of pteropods, likely indicating that in stressful situations this species may be cannibalistic. Order RUNCINIDA Family RUNCINIDEA H. Adams and A. Adams, 1854 Genus Runcina Forbes [in Forbes and Hanley], 1851	en	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): 265-310, DOI: 10.1080/00222933.2022.2040630, URL: http://dx.doi.org/10.1080/00222933.2022.2040630
024087ABD857D12A9AD92234FCC2FCA7.taxon	description	(Figure 5 (e ))	en	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): 265-310, DOI: 10.1080/00222933.2022.2040630, URL: http://dx.doi.org/10.1080/00222933.2022.2040630
024087ABD857D12A9AD92234FCC2FCA7.taxon	materials_examined	Material examined Cala d’Aiguafreda, Begur (Spain), 41 ° 57 ʹ 49 ” N, 3 ° 13 ʹ 41 ” E, 13 October 2017, 0.1 m depth, 7 spcs, adults, L = 2 – 3 mm; 21 November 2017, 0.1 m depth, 1 spc., adult, L = 2 mm; 31 January 2018, 0.1 m depth, 9 spcs, adults, L = 2 – 3 mm; 23 April 2018, 0.1 m depth, 2 spcs, adults, L = 3 mm; 25 May 2018, 0.1 m depth, 2 spcs, adults, L = 3 mm; Punta del Romaní, L’Escala (Spain), 42 ° 6 ʹ 54 ” N. 3 ° 10 ʹ 9 ” E, 10 January 2018, 0.2 m depth, 4 spcs, adults, L = 2 – 3 mm; 24 April 2018, 0.2 m depth, 3 spcs, adults, L = 2 – 3 mm; 7 December 2018, 0.2 m depth, 7 spcs, adults, L = 2 – 3 mm; Punta d’en Bosch, Sant Feliu de Guíxols (Spain), 41 ° 45 ʹ 54 ” N, 3 ° 0 ʹ 11 ” E, 17 April 2018, 0.1 m depth, 5 spcs, adults, L = 1 – 3 mm. External morphology Body elongate, narrow, black or brown in colour, rear tail darker. Foot large.	en	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): 265-310, DOI: 10.1080/00222933.2022.2040630, URL: http://dx.doi.org/10.1080/00222933.2022.2040630
024087ABD857D12A9AD92234FCC2FCA7.taxon	biology_ecology	Ecology Specimens found grazing on biofouling at night over calcarean red algae or boulders, in very superficial waters.	en	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): 265-310, DOI: 10.1080/00222933.2022.2040630, URL: http://dx.doi.org/10.1080/00222933.2022.2040630
024087ABD857D12A9AD92234FCC2FCA7.taxon	distribution	Distribution Atlantic Spanish coast: Canary Islands and Strait of Gibraltar (Cervera et al. 2004) and Mediterranean Spanish coast: Catalonia (this study).	en	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): 265-310, DOI: 10.1080/00222933.2022.2040630, URL: http://dx.doi.org/10.1080/00222933.2022.2040630
024087ABD857D12A9AD92234FCC2FCA7.taxon	discussion	Remarks This species is rarely observed and very small. Easily distinguishable from other Runcina species by its absence of spots and white marks and its uniform black colour (Quatrefages 1844). Superorder SACOGLOSSA Ihering, 1876 Family HERMAEIDAE H. Adams and A. Adams, 1854 Genus Aplysiopsis Deshayes, 1853	en	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): 265-310, DOI: 10.1080/00222933.2022.2040630, URL: http://dx.doi.org/10.1080/00222933.2022.2040630
024087ABD850D12B9ADE2477FEA0FE87.taxon	description	(Figure 5 (f ))	en	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): 265-310, DOI: 10.1080/00222933.2022.2040630, URL: http://dx.doi.org/10.1080/00222933.2022.2040630
024087ABD850D12B9ADE2477FEA0FE87.taxon	materials_examined	Material examined Cova de l’infern (Spain), 42 ° 19 ʹ 2.75 ” N, 3 ° 19 ʹ 12.74 ” E, 19 November 2017, 1.2 m depth, 5 spcs, adults and egg masses, L = 15 – 20 mm; Cala Maset caves, Sant Feliu de Guíxols (Spain), 41 ° 47 ʹ 10 ” N, 3 ° 2 ʹ 44 ” E, 13 September 2019, 1.3 m depth, 1 spc., adult, L = 15 mm; Punta de la Mona, Andalucía (Spain), 36 ° 43 ʹ 12.9 ” N 3 ° 43 ʹ 43.1 ” W, 19 September 2020, 3 m depth, 1 spc., adult and egg masses, L = 20 mm. External morphology Body elongate, narrow, background colour white with longitudinal dark red lines on dorsum and lateral body parts. Cerata long, smooth; background colour green with white punctuation, dark red vertical lines, pink on tips.	en	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): 265-310, DOI: 10.1080/00222933.2022.2040630, URL: http://dx.doi.org/10.1080/00222933.2022.2040630
024087ABD850D12B9ADE2477FEA0FE87.taxon	biology_ecology	Ecology Specimens were found feeding on the green alga Cladophora prolifera (Roth) Kützing, 1843. The egg mass is whitish, cylindrical, found associated with algae. The specimen observed in 2019 was found at night crawling over algae, while the 2017 specimens were hidden inside algae. This could mean that slugs are mostly nocturnal, hiding among algae during the day.	en	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): 265-310, DOI: 10.1080/00222933.2022.2040630, URL: http://dx.doi.org/10.1080/00222933.2022.2040630
024087ABD850D12B9ADE2477FEA0FE87.taxon	distribution	Distribution Greece (OBIS 2021); Croatia (Mavrič et al. 2014); Spain: Canary Islands (Ortea et al. 1998, 2001), Balearic Islands (Ballesteros and Templado 1996), Catalonia (this study).	en	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): 265-310, DOI: 10.1080/00222933.2022.2040630, URL: http://dx.doi.org/10.1080/00222933.2022.2040630
024087ABD850D12B9ADE2477FEA0FE87.taxon	discussion	Remarks This species is rarely observed. It is found among algae, especially Cystoseira, Cladophora and Halopteris scoparia (Linnaeus) Sauvageau, 1904 (Mavrič et al. 2014), and probably feeds on them.	en	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): 265-310, DOI: 10.1080/00222933.2022.2040630, URL: http://dx.doi.org/10.1080/00222933.2022.2040630
024087ABD851D1289AF42646FCC8FF30.taxon	description	(Figure 5 (g ))	en	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): 265-310, DOI: 10.1080/00222933.2022.2040630, URL: http://dx.doi.org/10.1080/00222933.2022.2040630
024087ABD851D1289AF42646FCC8FF30.taxon	materials_examined	Material examined Cala d’Aiguafreda, Begur (Spain), 41 ° 57 ʹ 49 ” N, 3 ° 13 ʹ 41 ” E, 5 September 2017, 0.8 m depth, 2 spcs, adults, L = 17 mm; CalaVentosa, Sant Feliu de Guíxols (Spain), 41 ° 47 ʹ 5 ” N, 3 ° 2 ʹ 52 ” E, 13 September 2017, 1.5 m depth, 1 spc., adult, L = 20 mm; Cala Maset caves, Sant Feliu de Guíxols (Spain), 41 ° 47 ʹ 10 ” N, 3 ° 2 ʹ 44 ” E, 5 December 2017, 0.7 m depth, 9 spcs, adults and egg masses, L = 5 – 40 mm; Fòrum pools, Barcelona (Spain), 41 ° 24 ʹ 34.5 ” N, 2 ° 13 ʹ 36.8 ” E, 5 December 2017, 0.7 m depth, 8 spcs, juveniles, adults and egg masses, L = 5 – 40 mm; Cova de l’infern (Spain), 42 ° 19 ʹ 2.75 ” N, 3 ° 19 ʹ 12.74 ” E, 18 September 2018, 1.3 m depth, 1 spc., adult and egg masses, L = 40 mm; Punta de la Mona, Andalucía (Spain), 36 ° 43 ʹ 12.9 ” N 3 ° 43 ʹ 43.1 ” W, 20 September 2020, 1 – 5 m depth,> 40 spcs, juveniles, adults and egg masses, L = 4 – 30 mm. External morphology Body elongate, thick, background colour light green with small brown and white dots along body, and a white pigmented area between eyes. Cerata numerous, flat; transparent with green lines running towards apex. Rhinophores long, folded, divided in ‘ Y’ shape, tips divided into two unequal parts.	en	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): 265-310, DOI: 10.1080/00222933.2022.2040630, URL: http://dx.doi.org/10.1080/00222933.2022.2040630
024087ABD851D1289AF42646FCC8FF30.taxon	biology_ecology	Ecology Specimens found at night and during the day on the green algae Bryopsis duplex (De Notaris, 1844) and Cladophora prolifera laying egg masses. At night slugs actively crawled and laid egg masses, while by day they hid among the algae.	en	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): 265-310, DOI: 10.1080/00222933.2022.2040630, URL: http://dx.doi.org/10.1080/00222933.2022.2040630
024087ABD851D1289AF42646FCC8FF30.taxon	distribution	Distribution Gulf of Mexico (BioGoMx 2021); Brazil (GBIF. org 2021); Gibraltar (García-Gómez 2002); Atlantic Spanish coast: Canary Islands (Ortea and Bacallado 1981; Ortea et al. 1999, 2001; Moro et al. 2003); Mediterranean Spanish coast, Andalucía (Luque 1983; García Raso et al. 1992; Ocaña et al. 2000), Levantine coast (Templado et al. 1987, 2002), Balearic Islands (GROC 2009 – 2021), Catalonia (this study).	en	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): 265-310, DOI: 10.1080/00222933.2022.2040630, URL: http://dx.doi.org/10.1080/00222933.2022.2040630
024087ABD851D1289AF42646FCC8FF30.taxon	discussion	Remarks This species is distinguished from similar ones like C. viridis (Deshayes, 1857) (formerly Polybranchia viridis) by the presence of a ramified digestive gland in the cerata (see Poybranchia viridis in Rudman 2021). Genus Cyerce Bergh, 1870	en	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): 265-310, DOI: 10.1080/00222933.2022.2040630, URL: http://dx.doi.org/10.1080/00222933.2022.2040630
024087ABD852D1289AD427F7FCE1FAC6.taxon	description	(Figure 5 (h ))	en	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): 265-310, DOI: 10.1080/00222933.2022.2040630, URL: http://dx.doi.org/10.1080/00222933.2022.2040630
024087ABD852D1289AD427F7FCE1FAC6.taxon	materials_examined	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.	en	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): 265-310, DOI: 10.1080/00222933.2022.2040630, URL: http://dx.doi.org/10.1080/00222933.2022.2040630
024087ABD852D1289AD427F7FCE1FAC6.taxon	biology_ecology	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.	en	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): 265-310, DOI: 10.1080/00222933.2022.2040630, URL: http://dx.doi.org/10.1080/00222933.2022.2040630
024087ABD852D1289AD427F7FCE1FAC6.taxon	distribution	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).	en	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): 265-310, DOI: 10.1080/00222933.2022.2040630, URL: http://dx.doi.org/10.1080/00222933.2022.2040630
024087ABD852D1289AD427F7FCE1FAC6.taxon	discussion	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	en	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): 265-310, DOI: 10.1080/00222933.2022.2040630, URL: http://dx.doi.org/10.1080/00222933.2022.2040630
024087ABD852D1169AAC2255FD46FC74.taxon	description	(Figure 6 (a ))	en	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): 265-310, DOI: 10.1080/00222933.2022.2040630, URL: http://dx.doi.org/10.1080/00222933.2022.2040630
024087ABD852D1169AAC2255FD46FC74.taxon	materials_examined	Material examined Cala d’Aiguafreda, Begur (Spain), 41 ° 57 ʹ 49 ” N, 3 ° 13 ʹ 41 ” E, 31 March 2017, 1 m depth, 9 spcs, adults, L = 7 – 12 mm; 25 December 2017, 1 m depth, 5 spcs, adults and juveniles; Cala Maset caves, Sant Feliu de Guíxols (Spain), 41 ° 47 ʹ 10 ” N, 3 ° 2 ʹ 44 ” E, 31 December 2017, 0.7 m depth, 2 spcs, juvenile and adult, L = 2 – 6 mm; 8 March 2018, 1.4 m depth, 2 spcs, adults and egg masses, L = 12 mm; Cala Sa Tuna, 41 ° 57 ʹ 38 ” N, 3 ° 13 ʹ 52 ” E, 3 January 2018, 0.8 m depth, 4 spcs, adults, L = 5 – 7 mm; Punta del Romaní, L’Escala (Spain), 42 ° 6 ʹ 54 ” N, 3 ° 10 ʹ 9 ” E, 6 January 2018, 0.7 m depth, 1 spc., juvenile, L = 2 mm; Cala Trons, Lloret de Mar (Spain), 41 ° 41 ʹ 57 ” N, 2 ° 51 ʹ 52 ” E, 20 January 2018, 1.7 m depth, 1 spc., adult, L = 12 mm. External morphology Body elongate, narrow, background colour red and semi-transparent, with dispersed white dots concentrated around head, cerata and rhinophore apexes. Cerata globular, leaf-shaped, semi-transparent, with internal lines of red colour running towards apex and surrounded by four tubercles. Rhinophores beige, internally rolled, bifid with superior apex slightly longer than inferior one.	en	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): 265-310, DOI: 10.1080/00222933.2022.2040630, URL: http://dx.doi.org/10.1080/00222933.2022.2040630
024087ABD852D1169AAC2255FD46FC74.taxon	biology_ecology	Ecology Specimens were found on the red alga Bornetia secundiflora (J. Agardh) Thuret, 1855, where they were mating and laying the eggs. The egg mass is whitish, cylindrical and ‘ C’ - shaped (Figure 5 (b), close-up); they were laid under the algae, around B. secundiflora but not on it.	en	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): 265-310, DOI: 10.1080/00222933.2022.2040630, URL: http://dx.doi.org/10.1080/00222933.2022.2040630
024087ABD852D1169AAC2255FD46FC74.taxon	distribution	Distribution Central American coast and England (iNaturalist. org 2021); Portugal (Cervera et al. 2004); Gibraltar (García-Gómez 2002); Spain: Galicia (Rolán 1983), Andalucía (Cervera et al. 1988), Levantine coast (Templado 1982; Templado et al. 1983, 1984; Marín and Ros 1988), Balearic Islands, Spain (GROC 2009 – 2021), Catalonia (Ballesteros et al. 2016; this study); France (Rudman 2021).	en	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): 265-310, DOI: 10.1080/00222933.2022.2040630, URL: http://dx.doi.org/10.1080/00222933.2022.2040630
024087ABD852D1169AAC2255FD46FC74.taxon	discussion	Remarks In the Spanish Balearic Islands this species was reported on the invasive alga Lophocladia lallemandii (Montagne) F. Schmitz, 1893 (GROC 2009 – 2021), off Catalonia we commonly found it on B. secundiflora; juvenile specimens had a fluorescent orange colouration on their cerata, similar in colour to the latter alga.	en	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): 265-310, DOI: 10.1080/00222933.2022.2040630, URL: http://dx.doi.org/10.1080/00222933.2022.2040630
024087ABD86CD1179A162309FB86FE54.taxon	description	(Figure 6 (b ))	en	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): 265-310, DOI: 10.1080/00222933.2022.2040630, URL: http://dx.doi.org/10.1080/00222933.2022.2040630
024087ABD86CD1179A162309FB86FE54.taxon	materials_examined	Material examined Es Caials, Cadaqués (Spain), 42 ° 17 ʹ 5.1 ” N, 3 ° 17 ʹ 50 ” E, 20 February 2010 10 m depth, 2 spcs, adults, H = 6 – 10 mm; Tamariu beach (Spain), 41 ° 55 ʹ 0.5 ” N, 3 ° 12 ʹ 27.1 ” E, 11 February 2019, 5 m depth, 1 spc., adult, L = 5 mm. External morphology Body elongate, narrow, background colour semi-transparent, with two lateral and two dorsal red narrow lines close to eyes, little visible at the end of body. Cerata globular, semi-transparent, with red digestive gland seen by transparency running towards apex, external white punctuations scattered throughout but most concentrated into two tubercles before each ceras top. Rhinophores beige in apical part, with a central red line and white coloured scattered dots.	en	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): 265-310, DOI: 10.1080/00222933.2022.2040630, URL: http://dx.doi.org/10.1080/00222933.2022.2040630
024087ABD86CD1179A162309FB86FE54.taxon	biology_ecology	Ecology The specimen was found in a red filamentous alga sample at superficial depths. Distribution North Spanish coast (Caballer and Ortea 2015); Catalonia (GROC 2009 – 2021; this study).	en	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): 265-310, DOI: 10.1080/00222933.2022.2040630, URL: http://dx.doi.org/10.1080/00222933.2022.2040630
024087ABD86CD1179A162309FB86FE54.taxon	discussion	Remarks This species is distinguished from H. bifida by the presence of red lines that run from the rhinophores, passing between the eyes, to the dorsum, the absence of oral appendages (present in H. bifida), and a less ramified digestive gland (Caballer and Ortea 2015). The species description of H. cantabra was only established in 2015, and thus some previous records of H. bifida in the Iberian Peninsula could be misidentifications (e. g. Salvat 1968; Ortea 1977).	en	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): 265-310, DOI: 10.1080/00222933.2022.2040630, URL: http://dx.doi.org/10.1080/00222933.2022.2040630
024087ABD86DD1179AC72526FCADF957.taxon	description	(Figure 6 (c ))	en	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): 265-310, DOI: 10.1080/00222933.2022.2040630, URL: http://dx.doi.org/10.1080/00222933.2022.2040630
024087ABD86DD1179AC72526FCADF957.taxon	materials_examined	Material examined Cala Maset caves, Sant Feliu de Guíxols (Spain), 41 ° 47 ʹ 10 ” N, 3 ° 2 ʹ 44 ” E, 5 January 2018, 0.4 m depth, 3 spcs, adults and copulation, L = 2 – 3 mm. External morphology Body elongate, narrow, background colour translucent white, with red lines on dorsum from apex of rhinophores to tail, and on laterals from eyes; with white opaque dots scattered on dorsum. Cerata club-shaped, red in colour, with white punctuation more concentrated in apex. Rhinophores internally rolled, posterior part longer than anterior part, transparent white with opaque white dots.	en	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): 265-310, DOI: 10.1080/00222933.2022.2040630, URL: http://dx.doi.org/10.1080/00222933.2022.2040630
024087ABD86DD1179AC72526FCADF957.taxon	biology_ecology	Ecology Specimens found feeding and mating on the red alga Antithamnion cruciatum (C. Agardh) Nägeli, 1847 and were active at night.	en	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): 265-310, DOI: 10.1080/00222933.2022.2040630, URL: http://dx.doi.org/10.1080/00222933.2022.2040630
024087ABD86DD1179AC72526FCADF957.taxon	distribution	Distribution The species description of this slug was from specimens in Atlantic waters of Morocco and Senegal (Pruvot-Fol 1953); also found in Portugal (Cervera et al. 2004); Gibraltar (Cervera and García-Gómez 1986); Spain: Canary Islands, Andalucía, Galicia, Cantabric Sea, Levantine coast (Cervera et al. 2004), Catalonia (Ballesteros et al. 2016; this study).	en	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): 265-310, DOI: 10.1080/00222933.2022.2040630, URL: http://dx.doi.org/10.1080/00222933.2022.2040630
024087ABD86DD1179AC72526FCADF957.taxon	discussion	Remarks This species is distinguished from H. bifida by having more globular and rounded cerata, and more abundant white body punctuation (Salvat 1968). Hermaea paucicirra can be differentiated from its sympatric species H. cantabra by the presence of a more opaque white body with a red mark on the eyes. Because the epidermal red pigmentation on the dorsum obscures the digestive gland as it also happens with the cerata, not as in H. cantabra (Caballer and Ortea 2015). Family LIMAPONTIIDAE Gray, 1847 Genus Limapontia Johnston, 1836	en	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): 265-310, DOI: 10.1080/00222933.2022.2040630, URL: http://dx.doi.org/10.1080/00222933.2022.2040630
024087ABD86ED1149AF627ADFCF4FB02.taxon	description	(Figure 6 (d ))	en	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): 265-310, DOI: 10.1080/00222933.2022.2040630, URL: http://dx.doi.org/10.1080/00222933.2022.2040630
024087ABD86ED1149AF627ADFCF4FB02.taxon	materials_examined	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.	en	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): 265-310, DOI: 10.1080/00222933.2022.2040630, URL: http://dx.doi.org/10.1080/00222933.2022.2040630
024087ABD86ED1149AF627ADFCF4FB02.taxon	biology_ecology	Ecology Specimens found in brackish waters on substrate extensively covered by the green alga Ulva lactuca Linnaeus, 1753.	en	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): 265-310, DOI: 10.1080/00222933.2022.2040630, URL: http://dx.doi.org/10.1080/00222933.2022.2040630
024087ABD86ED1149AF627ADFCF4FB02.taxon	distribution	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).	en	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): 265-310, DOI: 10.1080/00222933.2022.2040630, URL: http://dx.doi.org/10.1080/00222933.2022.2040630
024087ABD86ED1149AF627ADFCF4FB02.taxon	discussion	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	en	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): 265-310, DOI: 10.1080/00222933.2022.2040630, URL: http://dx.doi.org/10.1080/00222933.2022.2040630
024087ABD86ED1159AA6238CFF0BFC13.taxon	description	(Figure 6 (e ))	en	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): 265-310, DOI: 10.1080/00222933.2022.2040630, URL: http://dx.doi.org/10.1080/00222933.2022.2040630
024087ABD86ED1159AA6238CFF0BFC13.taxon	materials_examined	Material examined Fòrum pools, Barcelona (Spain), 41 ° 24 ʹ 34.5 ” N, 2 ° 13 ʹ 36.8 ” E, 23 November 2017, 0.4 m depth, 12 spcs, juveniles, adults and egg masses, L = 3 – 20 mm; le Ponton, Étang de Thau, Sète (France), 43 ° 25 ʹ 28.5 ” N, 3 ° 42 ʹ E, 21 May 2018, 0.5 m depth, 3 spcs, adults, L = 17 – 25 mm; Cala Maset caves, Sant Feliu de Guíxols (Spain), 41 ° 47 ʹ 10 ” N, 3 ° 2 ʹ 44 ” E, 19 December 2018, 2 m depth, 2 spcs, adults and egg masses, L = 10 – 15 mm; 1 January 2019, 1.3 m depth, 3 spcs, adults, L = 13 – 15 mm; Cala Sa Tuna, Begur (Spain), 41 ° 57 ʹ 38 ” N, 3 ° 13 ʹ 52 ” E, 31 January 2019, 0.5 m depth, 1 spc., juvenile, L = 3 mm; Tamariu Beach (Spain), 41 ° 55 ʹ 0.5 ” N, 3 ° 12 ʹ 27.1 ” E, 10 September 2019, 1 m depth, 4 spcs, adults with egg masses, L = 10 – 20 mm; Punta de la Mona, Andalucía (Spain), 36 ° 43 ʹ 12.9 ” N, 3 ° 43 ʹ 43.1 ” W, 19 September 2020, 2 m depth, 2 spcs, adults, L = 15 – 20 mm. External morphology Body elongate, narrow, background colour white and semi-transparent with a central white circle on dorsum. Lateral body parts and foot with dark brown or purple colour. Cerata long, smooth; background colour green, with white spots, tip dark garnet in colour. Rhinophores smooth, large, with white dots concentrated at apexes. Oral tentacles wide and short.	en	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): 265-310, DOI: 10.1080/00222933.2022.2040630, URL: http://dx.doi.org/10.1080/00222933.2022.2040630
024087ABD86ED1159AA6238CFF0BFC13.taxon	biology_ecology	Ecology Specimens found in masses of the green alga Bryopsis duplex, mating, and laying whitish and cylindrical egg masses at the base of the alga. This species can go completely unnoticed within the algal masses; moves actively at night.	en	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): 265-310, DOI: 10.1080/00222933.2022.2040630, URL: http://dx.doi.org/10.1080/00222933.2022.2040630
024087ABD86ED1159AA6238CFF0BFC13.taxon	distribution	Distribution Originally described from Italy: Genoa (Trinchese 1874), Gulf of Naples (Gascoigne and Sordi 1980); also, Portugal (Calado et al. 2003); Gibraltar (Cervera et al. 1988); Spain: Andalusian coast (this study), Catalonia (this study); France (this study).	en	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): 265-310, DOI: 10.1080/00222933.2022.2040630, URL: http://dx.doi.org/10.1080/00222933.2022.2040630
024087ABD86ED1159AA6238CFF0BFC13.taxon	discussion	Remarks This species can be misidentified as P. vidiris (Trinchese, 1874), but it is distinguishable by its brown or purple body margins and the tip of the cerata darkly coloured in garnet (Pruvot-Fol 1954).	en	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): 265-310, DOI: 10.1080/00222933.2022.2040630, URL: http://dx.doi.org/10.1080/00222933.2022.2040630
024087ABD86FD1129AA724EAFD1EFE61.taxon	description	(Figure 6 (f ))	en	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): 265-310, DOI: 10.1080/00222933.2022.2040630, URL: http://dx.doi.org/10.1080/00222933.2022.2040630
024087ABD86FD1129AA724EAFD1EFE61.taxon	materials_examined	Material examined Cala Ventosa, Sant Feliu de Guíxols (Spain), 41 ° 47 ʹ 5 ” N, 3 ° 2 ʹ 52 ” E, 13 September 2017, 0.1 m depth, 5 spcs, adults and egg masses, L = 7 – 20 mm; Cala Sa Tuna, 41 ° 57 ʹ 38 ” N, 3 ° 13 ʹ 52 ” E, 8 March 2018, 0.1 m depth, 6 spcs, juveniles and adults, L = 2 – 15 mm; Punta d’en Bosch, Sant Feliu de Guíxols (Spain), 41 ° 45 ʹ 54 ” N, 3 ° 0 ʹ 11 ” E, 17 April 2018, 0.1 m depth, 5 spcs, adults and egg masses, L = 12 – 20 mm. External morphology Body elongate, narrow, background colour white and semi-transparent with digestive branches of dark green. Cerata long, smooth; background colour dark green, with white punctuation, apex white. Rhinophores long, translucent white with green branches and white punctuation on tips.	en	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): 265-310, DOI: 10.1080/00222933.2022.2040630, URL: http://dx.doi.org/10.1080/00222933.2022.2040630
024087ABD86FD1129AA724EAFD1EFE61.taxon	biology_ecology	Ecology Specimens found on the green alga Bryopsis mucosa (J. V. Lamouroux, 1809) laying cylindrical and white egg masses. Specimens in this study were found within a few centimetres’ depth feeding on B. mucosa, which is commonly found at subtidal depths.	en	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): 265-310, DOI: 10.1080/00222933.2022.2040630, URL: http://dx.doi.org/10.1080/00222933.2022.2040630
024087ABD86FD1129AA724EAFD1EFE61.taxon	distribution	Distribution Israel (Monselise and Mienis 1977); Greece and Black Sea (OBIS 2021); Italy (Ballesteros et al. 2012 – 2021); Spain: Catalonia (Cervera et al. 2004; this study); France (this study).	en	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): 265-310, DOI: 10.1080/00222933.2022.2040630, URL: http://dx.doi.org/10.1080/00222933.2022.2040630
024087ABD86FD1129AA724EAFD1EFE61.taxon	discussion	Remarks See the Remarks section on P. tardyi above. Family PLAKOBRANCHIDAE Gray, 1840 Genus Elysia Risso, 1818	en	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): 265-310, DOI: 10.1080/00222933.2022.2040630, URL: http://dx.doi.org/10.1080/00222933.2022.2040630
024087ABD868D1129A902518FCB0F9C7.taxon	description	(Figure 6 (g ))	en	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): 265-310, DOI: 10.1080/00222933.2022.2040630, URL: http://dx.doi.org/10.1080/00222933.2022.2040630
024087ABD868D1129A902518FCB0F9C7.taxon	materials_examined	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.	en	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): 265-310, DOI: 10.1080/00222933.2022.2040630, URL: http://dx.doi.org/10.1080/00222933.2022.2040630
024087ABD868D1129A902518FCB0F9C7.taxon	biology_ecology	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.	en	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): 265-310, DOI: 10.1080/00222933.2022.2040630, URL: http://dx.doi.org/10.1080/00222933.2022.2040630
024087ABD868D1129A902518FCB0F9C7.taxon	distribution	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).	en	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): 265-310, DOI: 10.1080/00222933.2022.2040630, URL: http://dx.doi.org/10.1080/00222933.2022.2040630
024087ABD868D1129A902518FCB0F9C7.taxon	discussion	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	en	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): 265-310, DOI: 10.1080/00222933.2022.2040630, URL: http://dx.doi.org/10.1080/00222933.2022.2040630
024087ABD868D1139ADB2151FB8CFB4C.taxon	description	(Figure 6 (h ))	en	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): 265-310, DOI: 10.1080/00222933.2022.2040630, URL: http://dx.doi.org/10.1080/00222933.2022.2040630
024087ABD868D1139ADB2151FB8CFB4C.taxon	materials_examined	Material examined Cala Maset caves, Sant Feliu de Guíxols (Spain), 41 ° 47 ʹ 10 ” N, 3 ° 2 ʹ 44 ” E, 30 September 2020, 1 m depth, 4 spcs, adults and egg masses, L = 2 – 5 mm; 31 October 2020, 1 m depth, 2 spcs, juveniles, L = 2 mm; 12 December 2020, 1 m depth, 1 spc., juvenile, L = 2 mm; 22 December 2020, 1 m depth, 2 spcs, juveniles, L = 2 mm; 31 December 2020, 1 m depth, 2 spcs, juveniles, L = 2 mm; 14 January 2021, 1 m depth, 2 spcs, juveniles, L = 2 mm; 27 February 2021, 1 m depth, 2 spcs, juveniles, L = 2 mm; Barceloneta Beach, Barcelona (Spain), 41 ° 22 ʹ 49.5 ” N, 2 ° 11 ʹ 43.3 ” E, 30 April 2021, 4 m depth, 1 spc., juvenile, L = 1 mm. External morphology Shell external, patelliform, covering entire body; protoconch on the posterior part, farther from the head; with white longitudinal lines, background red. Body background beige to white with concentrations of red marks in the front.	en	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): 265-310, DOI: 10.1080/00222933.2022.2040630, URL: http://dx.doi.org/10.1080/00222933.2022.2040630
024087ABD868D1139ADB2151FB8CFB4C.taxon	biology_ecology	Ecology All specimens found in communities of the red alga Peyssonnelia rosa-marina Boudouresque and Denizot, 1973, grazing and laying the egg masses at night.	en	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): 265-310, DOI: 10.1080/00222933.2022.2040630, URL: http://dx.doi.org/10.1080/00222933.2022.2040630
024087ABD868D1139ADB2151FB8CFB4C.taxon	distribution	Distribution Throughout the Mediterranean and the eastern Atlantic, in the Azores, Cavo Verde, the Canary Islands and the north-eastern African coast (GBIF. org 2021).	en	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): 265-310, DOI: 10.1080/00222933.2022.2040630, URL: http://dx.doi.org/10.1080/00222933.2022.2040630
024087ABD868D1139ADB2151FB8CFB4C.taxon	discussion	Remarks Williamia gussoni could be confused with the sympatric Tectura virginea (O. F. Müller, 1776), from which it can be distinguished by the absence of long oral tentacles typical of Tectura. Also, in Tectura the apical part of the shell is in the anterior segment of the body, near the head. The pattern of the shell ribs is also different, with a greater number of vertical and more irregularly distributed white lines. Remarkably, the photograph herein is, to our knowledge, the first one taken of live W. gussoni specimens in their habitat. This species has been widely cited based only on shells found on sediments, with scarce data on living specimens, related to red algae of the genus Peyssonnelia Decaisne, 1841. In our study, we observed a specimen from 31 October 2020 until 27 February 2021, always on the same algal frond of P. rosa-marina.	en	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): 265-310, DOI: 10.1080/00222933.2022.2040630, URL: http://dx.doi.org/10.1080/00222933.2022.2040630
