AEOLIDIIDAE GRAY, 1827

Carmona, Leila, Lei, Bonnie R., Pola, Marta, Gosliner, Terrence M., Valdés, Ángel & Cervera, Juan Lucas, 2014, Untangling the Spurilla neapolitana (Delle Chiaje, 1841) species complex: a review of the genus Spurilla Bergh, 1864 (Mollusca: Nudibranchia: Aeolidiidae), Zoological Journal of the Linnean Society 170 (1), pp. 132-154 : 135-144

FAMILY AEOLIDIIDAE GRAY, 1827

Type species

Eolis neapolitana Delle Chiaje, 1841 , by monotypy and subsequent designation by Bergh (1864).

Diagnosis of the genus Spurilla according to Bergh (1864):

Rhinophori perfoliati. Podarium angulis fere rotundatis. Processus masticatorius madibulae parce et minutissime denticulatus. Radula dentibus pectinatis uniseriatis.

Rhinophores perfoliate; foot corners rounded; masticatory process with minute denticles; radula pectinate and uniseriate.

SPURILLA NEAPOLITANA ( DELLE CHIAJE, 1841)

( FIGS 1A–F , 2A–B , 3A )

Eolis neapolitana Delle Chiaje, 1841 : vol. 6, pl. 73, figs 12–14; vol. 7, pl. 88, fig. 13–15 (1841); vol. 8, p. 7 (1844).

Eolidia neapolitana Vérany, 1846: 97 .

Facelina neapolitana ( Delle Chiaje, 1841) : Bergh, 1861: 321.

Spurilla neapolitana ( Delle Chiaje, 1841) : Bergh, 1864: 205, plate IIB, figs 1–16.

Eolis alderiana Deshayes & Frédol , in Frédol 1865: pl. XVII, fig. 7.

Flabellina neapolitana Costa, 1866: 71 , pl. 1, fig. 1.

Flabellina inornata Costa, 1866: 72 , pl. 2, fig. 6.

Spurilla inornata ( Costa, 1866) : Carus, 1889 –1893: 209.

Eolis conspersa Fischer, 1869: 7 .

? Spurilla mograbina Pruvot-Fol, 1953: 52 , pl. I, fig. 12, pl. II, fig. 27.

Spurilla vayssierei García-Gómez & Cervera, 1985: 154 .

Material examined

MNCN 15.05 /63451, one specimen, dissected, 25 mm in length preserved, Spain, Huelva , El Portil, collected by Sergio García-Gómez , 09.iv.09; MNCN 15.05 /63452, one specimen, dissected, 23 mm in length preserved, Spain, Huelva , El Portil, collected by Sergio García-Gómez , 09.iv.09; MNCN 15.05 / 63453, one specimen, dissected, 25 mm in length preserved, Balearic Is., Menorca, Cap Cavalleria, collected by Naoufal Tamsouri , 25.v.08; MNCN 15.05 / 63454, one specimen, dissected, 20 mm in length preserved, Balearic Is., Menorca, Cap Cavalleria, collected by Naoufal Tamsouri , 25.v.08; MNCN 15.05 / 63455, one specimen, dissected, 12 mm in length preserved, Spain, Cádiz , Santa María, collected by J. Lucas Cervera , 14.xii.94; MNCN 15.05 /63465, one specimen, 10 mm in length preserved, Spain, Huelva , El Portil, collected by Sergio García-Gómez , 09.iv.12; LACM 178563 , one specimen, dissected, 10 mm in length preserved, North of Spain, collected by Ismael Mata Valdés , 07.viii.12; CASIZ 175756 , one specimen, dissected, 14 mm in length preserved, Portugal, Algarve , Ponta da Baleeira, collected by Yolanda Camacho-García , 08.vii.02; CASIZ 072582 , one specimen, dissected, 20 mm in length preserved, Azores, Ilha São Miguel , Ilheu de Vila Franca, collected by Terrence M. Gosliner , 14.vii.88; MNCN 15.05 /63463, one specimen, dissected, 13 mm in length alive, France, Cap Ferret , Grand Piquey, collected by Marina Poddubetskaia , 18.ix.04 ; MNCN 15.05 /63464, one specimen, dissected, 22 mm in length alive, France, Cap Ferret , Grand Piquey, collected by Marina Poddubetskaia , 18.ix.04 ; MNCN 15.05 /63467, one specimen, 10 mm in length alive, France, Cap Ferret , Hortense Sud, collected by Marina Poddubetskaia , 09.ix.12 ; CASIZ 192384 , one specimen, 13 mm in length preserved, France, Cap Ferret , collected by Marina Poddubetskaia , 18.iv.09 ; MNCN 15.05 /63458, one specimen, dissected, 24 mm in length preserved, Italy, Gulf of Naples , collected by Guido Villani , 17.iii.09; MNCN 15.05 /63459, one specimen, dissected, 20 mm in length preserved, Italy, Gulf of Naples , collected by Guido Villani , 17.iii.09; MNCN 15.05 /63466, one specimen, 10 mm in length preserved, Italy, Gulf of Naples , collected by Guido Villani , 17.iii.09; MNCN 15.05 /63461, one specimen, dissected, 9 mm in length preserved, Croatia, Catoro, collected by Tancredi D’Onofrio , 09.xii.07; MNCN 15.05 /63462, one specimen, dissected, 12 mm in length preserved, Croatia, Catoro, collected by Tancredi D’Onofrio , 09.xxii.07; MNCN 15.05 /63460, one specimen, dissected, 15 mm in length preserved, Morocco, Agadir, Sidi Boulfdail, collected by Naoufal Tamsouri , 10.iv.09; MNCN 15.05 /63456, one specimen, dissected, 18 mm in length preserved, Senegal, collected by Marina Poddubetskaia , 08.vi.05 ; MNCN 15.05 /63457, one specimen, dissected, 24 mm in length preserved, Senegal, collected by Marina Poddubetskaia , 08.vi.05 ;.

Geographical distribution

Originally described from the Mediterranean Sea ( Delle Chiaje, 1841), this species has been reported from Israel ( Schlesinger et al., 2009) to Málaga, Spain ( Luque, 1983, 1986), including the Balearic Islands ( Ballesteros, Álvarez & Mateo, 1986). Within the eastern Atlantic, its geographic distribution ranges from Arcachon ( France) ( Bouchet & Tardy, 1976) to Cape Verde (Ev. Marcus & Er. Marcus, 1962), including the island of Madeira ( Wirtz, 1999), the Azores ( Wirtz, 1998; Malaquias, 2001), Tarifa, Spain ( García-Gómez & Cervera, 1985), the Canary Islands (Ev. Marcus & Er. Marcus, 1962; Ortea et al., 2001; Wirtz & Debelius, 2003), Morocco (present study), and Senegal (present study).

External morphology ( Fig. 1A–F )

The body is elongate and moderately broad, tapering gradually to the tail. The anterior foot corners extend into tentaculiform processes. The body colour is highly variable: it ranges from translucent ( Fig. 1A–E ) to bright orange ( Fig. 1F ). White spots are present all over the dorsum. Depending on the specimen, these white spots can be more or less conspicuous. In some areas, mainly over the head and the pericardium, the white spots can form a somewhat continuous patch. Some specimens also have a fine pattern of white pigmentation that covers the whole notum. Because of the presence of symbiotic zooxanthellae, a dark brown or dull olive green pattern of reticulations is easily distinguishable in most of the specimens, going from the head (including rhinophores), where it is more evident, and including the foot edges, to the posterior end of the body.

The rhinophores, the oral tentacles, and the foot corners are coloured similarly to the background of the animal. The rhinophores are perfoliate, bearing up to 25 lamellae. They are somewhat shorter than the oral tentacles. All the specimens have rhinophores with white apices, but some of them also have white or cream pigment on the upper third of the rhinophores. The coloration of the tips of the oral tentacles is usually lighter than the background coloration. Some specimens, usually those with translucent body colour, have pinkish tips.

The cerata length is variable, but all are long and thick, narrower towards the tip, which curves inwards. The cerata extend from behind the rhinophores to the posterior end of the body, and are arranged in up to ten arches, leaving a distinct gap between pre and post-pericardial groups. Each arch contains between four and 39 cerata, decreasing in size towards the foot. The cerata are translucent, so the brownish green or greyish ramifications of the digestive gland are visible throughout the ceratal wall. The apices of the cerata are translucent white. The ceratal surface has white marks, although their density and size may vary. Some specimens also have purplish and/or pinkish pigment covering the whole surface of the cerata. The anus is cleioproctic, located within the second right ceratal arch. The genital opening is located among the cerata of the anteriormost group on the right.

Anatomy

The masticatory border of the jaws is finely denticulate ( Fig. 2A ). The radular formulae are 16 × 0.1.0 ( MNCN 15.05/63463, 13 mm; MNCN 15.05/63464, 22 mm) and 27 × 0.1.0 ( CASIZ 175756, 14 mm). The teeth are progressively smaller towards the posterior region of the radula. The radular teeth are biarched, with 24–60 elongate, fine, and acutely pointed denticles on either side of the small and triangular central cusp ( Fig. 2B ). The large, composite and conspicuous oral glands lie dorsolaterally to the buccal bulb. Salivary glands are absent.

The reproductive system is diaulic ( Fig. 3A ). The preampullary duct widens into the elongate ampulla. The latter narrows again before dividing into the oviduct and vas deferens. The elongate and thin vas deferens enters the wider proximal portion of the penial sac, which contains the unarmed penial papilla. The oviduct is short and connects to the moderately large receptaculum seminis. The remaining portion of the oviduct departs from the base of the receptaculum and enters the female gland. The vagina opens ventral to the penis.

Remarks

Eolis neapolitana was first illustrated by Delle Chiaje in 1841, but the description was not published until 3 years later in an appendix treating the genus Eolis ( Delle Chiaje, 1844: vol. 8, p. 7). Some authors (e.g. García-Gómez & Cervera, 1985) have given 1823 as the original date of publication; however, this species does not appear in the first edition of Delle Chiaje’s memoirs (1823–1830).

According to the literature, S. neapolitana is a nearly circumtropical species and displays a broad range of colour variation (e.g. Rudman, 1999 and Gosliner, Behrens & Valdés, 2008); however, our molecular data reveal the existence of several distinct species among the specimens assigned to this species. These results indicate that the geographical distribution of S. neapolitana is restricted to the Eastern Atlantic and Mediterranean. Despite this proposed reduction of its geographic and coloration ranges, S. neapolitana still covers a large portion of the northeastern Atlantic coast, from Cap Ferret ( France) to Cape Verde, and varies in body colour from translucent to bright orange ( Fig. 1 ).

The extensive colour variation of S. neapolitana is attributed to its varied diet rather than the geographical distribution of individuals ( Haefelfinger, 1969; Uribe & Pacheco, 2012). Another hypothesis is that this variability is associated with an ontogenetic change, as the paler morphotypes are usually the smaller specimens (less than 10 mm), whereas larger specimens usually have a darker coloration, mainly orange (L. Carmona, L. R. Bonnie, M. Pola, T. M. Gosliner, Á. Valdés & J. L. Cervera, pers. observ.). The intraspecific variation of the masticatory border of this species is widely accepted ( Gosliner, 1980; García-Gómez & Cervera, 1985). In fact, our specimens have both types of masticatory edge: minutely denticulate ( Fig. 2A ) and smooth (not shown). Although we could not find any ontogenetic variation pattern, the masticatory border without denticles is the most common in our specimens. García-Gómez & Cervera (1985) conducted the last published revision of the true S. neapolitana . Even though they examined a large number of specimens, they did not find any with a denticulate masticatory border. They proposed a new species, S. vayssierei , for specimens of Spurilla attributed to S. neapolitana with denticulate masticatory borders. Our results reject the validity of S. vayssierei because the ornamentation of the masticatory edge cannot be diagnostic in Spurilla , as a result of its intraspecific variation. Hence, we conclude that S. vayssierei is a junior synonym of S. neapolitana .

Spurilla mograbina , from Morocco, was described and illustrated by Pruvot-Fol (1953). The illustration clearly depicts a Spurilla species with perfoliate rhinophores, cerata curved inwards, and white and dull pink spots over the pinkish dorsum ( Pruvot-Fol, 1953: plate I, fig. 12); however, this colour pattern does not match any of the colour variations observed so far by us in S. neapolitana ( Fig. 1A–F ). Thus, with the available information it is not possible to determine the validity of this species with certainty; however, because the type locality of S. mograbina is well within the range of S. neapolitana , and both species are similar morphologically, we render S. mograbina as a possible junior synonym of S. neapolitana until more specimens become available.

SPURILLA SARGASSICOLA BERGH, 1871

( FIGS 2C–D , 3B , 4A–B )

Spurilla sargassicola Bergh, 1871: 161 , pl. XIII, figs 9–19.

Spurilla sp. Redfern, 2001: 181 , pl. 121, fig. 746A,B.

Material examined

CASIZ 184523 , one specimen, dissected, 4 mm in length preserved, Bahamas, Abaco, collected by Colin Redfern, 19.ii.04 ; MNCN 15.05 /63468, one specimen, dissected, 4 mm in length preserved, Bahamas, Abaco, collected by Colin Redfern, 16.ix.04 ; CASIZ 192385 , one specimen, dissected, 2 mm in length preserved, Bahamas, Abaco, collected by Colin Redfern, 17.ix.03 ; CPIC 00815 , one specimen, dissected, 11 mm in length preserved, Stocking Island , Bahamas, collected by Anne DuPont, 28.ii.09 ; CPIC 00816 , one specimen, dissected, 15 mm in length preserved, Bahamas, Stocking Island , collected by Anne DuPont, 28.ii.09 ; CPIC 00817 , one specimen, dissected, 11 mm in length preserved, Bahamas, Stocking Island , collected by Anne DuPont, 28.ii.09 .

Geographical distribution

Originally described from the Sargasso Sea ( Bergh, 1861; Redfern, 2001; Valdés et al., 2006), this species is also found in the Bahamas ( Valdés et al., 2006) and in the National Park Arrecife Alacranes ( Mexico) ( Sanvicente-Añorve et al., 2012).

External morphology ( Fig. 4A–B )

The body is elongate and slender, tapering gradually to the posterior end. The anterior foot corners extend into tentaculiform processes. The body colour is translucent pale brown, with a light ochre, greenish, or brownish reticulation pattern all over it. Because of the presence of the zooxanthellae, this pattern is more evident near the head and on the foot edges. Cream white spots are found all over the dorsum (from the head to the posterior end). Depending on the specimen, these spots can form a continuous patch, but never cover the sides of the animal, which are dark brown or dark ochre.

The coloration of the rhinophores ranges from pale cream to dark brown. They are somewhat shorter than the oral tentacles. The rhinophores are perfoliate, bearing between six and nine lamellae. The rhinophores of all the specimens have white apices, but some also have white or cream pigment on the upper third of the rhinophores, including the lamellae. The oral tentacles and the foot corners are the same colour as the body background. Some specimens have cream white marks on the oral tentacles.

The cerata length is variable, but they are usually short and thick, narrower towards the tip, which is curved inwards. Some other specimens have long and thin cerata. The cerata extend from behind the rhinophores to the posterior end of the body, and are arranged in up to seven arches, leaving a distinct gap between them. Each arch contains between three and seven cerata, decreasing in size towards the foot. The apices of the cerata are translucent white, and all the specimens have white marks all over the ceratal surface, although their density and size vary. Some specimens also have purplish and/or ochre pigment among the white spots. The cleioproctic anus is placed within the second right arch. The genital opening is located within the cerata of the anteriormost group on the right.

Anatomy

The masticatory border of the jaws is denticulate ( Fig. 2C ). The radular formulae are 10 × 0.1.0 ( MNCN 15.05/63468, 4 mm) and 18 × 0.1.0 ( CASIZ 184523, 4 mm). The teeth are progressively smaller in the posterior region of the radula. The radular teeth are biarched, with between eight and 14 moderately broad and acutely pointed denticles on either side of the small and triangular central cusp ( Fig. 2D ). The large, composite, and conspicuous oral glands lie dorsolaterally to the buccal bulb. Salivary glands are absent.

The reproductive system is diaulic ( Fig. 3B ). The preampullary duct widens into the short ampulla that narrows again before dividing into the oviduct and vas deferens. The conspicuous vas deferens enters the wider proximal portion of the penial sac, which contains the unarmed penial papilla. The short oviduct connects to a large receptaculum seminis. The remaining portion of the oviduct departs from the base of the receptaculum and enters the female gland. The vagina opens ventral to the penis.

Remarks

Some authors (e.g. Sanvicente-Añorve et al., 2012; Gofas, 2013) considered Bergh (1861) as the original date of publication of S. sargassicola ; however, Bergh (1861) did not provide a description of the animals, instead he provided descriptions of the ingested nematocysts. Thus, Bergh’s (1861) descriptions do not meet the criteria for a valid species description under Article 12 of the Code of Zoological Nomenclature ( ICZN, 1999), as no descriptions or illustrations of the actual animals, or indications, are provided. Bergh described S. sargassicola properly 10 years later ( Bergh, 1871); therefore, we consider Bergh (1871) as the real date of publication, and state the name proposed by Bergh (1861), Facelina ? sargassicola , as nomen nudum. On the other hand, Dautzenberg & Durouchoux (1906) reported S. sargassicola (under the name of Eolis sargarssicola ) from Saint-Malo, France. The specimens were described as large (up to 55 mm), with red rhinophores and oral tentacles. Hence, it seems evident that Dautzenberg & Durouchoux (1906) did not find S. sargassicola , as this species is mainly white and is restricted to the western Atlantic.

Spurilla sargassicola has been reported more often as a junior synonym of S. neapolitana than as a valid species; however, recent papers have challenged this view, and its status as a different species from S. neapolitana has become more widely accepted in recent years ( Valdés et al., 2006; Sanvicente-Añorve et al., 2012; Carmona et al., 2013). Our molecular results clearly separate S. sargassicola and S. neapolitana into two allopatric species. Spurilla sargassicola differs from S. neapolitana because of its predominately white coloration and its conspicuous gap between each ceratal group. Additionally, S. sargassicola also has distinct life-history characteristics, as it is usually found on free-living Sargassum and is the only pelagic species of Aeolidiidae . These morphological and ecological features also distinguish S. sargassicola from the remaining species of this genus.

As in the case of S. neapolitana , intraspecific variation of the masticatory edge was observed. Although Figure 2C shows somewhat conspicuous denticles over the masticatory border, some of our specimens have a smooth edge (not shown). As this variability is quite common within this genus (see S. neapolitana remarks), we do not consider this difference to be taxonomically significant.

This is the first publication that includes detailed descriptions of genitalia and oral glands of S. sargassicola .

SPURILLA BRAZILIANA MACFARLAND, 1909

( FIGS 2E–F , 3C , 4C–E )

Spurilla braziliana MacFarland, 1909: 91 , pl. XVI, XVII, XVIII. and XIX, figs 83–96.

Eolidina gabriellae Vannucci, 1952: 284–288 , figs 1–4.

Spurilla neapolitana var. braziliana Er. Marcus, 1955: 184 , pl. 29, figs 270–274.

Aeolidiella albopunctata Lin, 1992: 184 , figs 4–5.

Material examined

Holotype: CASIZ 019731 , one specimen, 23 mm dissected, Brazil, Algoas, collected by MacFarland, 28.vii.1899.

Other material: CASIZ 175737 , one specimen, dissected, 13 mm in length preserved, Costa Rica, Pacific Coast, Guanacaste, Punta Carbón , collected by Yolanda Camacho-García , 13.i.01; CASIZ 175735 , one specimen, dissected, 6 mm in length preserved, Costa Rica, Pacific Coast, Guanacaste, Punta Carbón , collected by Yolanda Camacho-García , 11.i.01; CASIZ 172374 , one specimen, dissected, 14 mm in length preserved, Panama, Pacific Coast, Golfo de Chiriqui, Isla Uva , collected by Mónica Medina , 16.ii.01; CASIZ 072111 , one specimen, dissected, 25 mm in length preserved, Mexico, Baja California Sur, Gulf of California , collected by Terrence M. Gosliner , 14.i.84; MNCN 15.05 /63471, one specimen, dissected, 10 mm in length preserved, Brazil, Cabo Frio , collected by Vinicius Padula , 16.viii.07; MNCN 15.05 /63472, one specimen, dissected, 10 mm in length preserved, Cuba, Playa Girón , collected by J. Lucas Cervera , 16.vii.08; CPIC 00810 , one specimen, dissected, 12 mm in length preserved, Peanut Island, Riviera Beach, Florida , collected by Anne DuPont , 08.xi.07; CPIC 00811 , one specimen, dissected, 11 mm in length preserved, Peanut Island, Riviera Beach, Florida , collected by Anne DuPont , 08.xi.07; CPIC 00813 , one specimen, dissected, 7 mm in length preserved, Peanut Island, Riviera Beach, Florida , collected by Anne DuPont , 08.xi.07; CASIZ 076124 , one specimen, dissected, 22 mm in length preserved, Hawaii, Oahu, Kewalo Basin , collected by Terrence M. Gosliner , xi.72; CASIZ 187750 , one specimen, dissected, 7 mm in length preserved, Japan, Honshu, Shizuoka Prefecture, Ose cape, collected by Rie Nakano , 07.vii.11.

Geographical distribution

Originally described from Alagoas, Brazil ( MacFarland, 1909), this species has been reported (under the name of S. neapolitana ) from the western Atlantic Coast: the Caribbean Sea ( Valdés et al., 2006), Florida, Mexico, Colombia, Cuba (the present study), Jamaica ( Miloslavich et al., 2010), Puerto Rico ( Miloslavich et al., 2010), and in the northern part of the Magellanic Province ( Forcelli, 2000). It has also been reported from the Pacific: Hawaiian Islands ( Kay, 1979; Gosliner, 1980; Pittman & Fiene, 2013), the Pacific coast of Costa Rica ( Camacho-García et al., 2005), Peru ( Uribe & Pacheco, 2012), Japan ( Hamatani, 2000), China ( Lin, 1992), and Australia ( Willan, 2006).

External morphology ( Fig. 4C–E )

The body is elongate and moderately broad, tapering gradually to the posterior end. The anterior foot corners extend into tentaculiform processes. The body colour is variable. This variability results from ontogenetic changes ( Domínguez et al., 2008). The youngest individuals are cream white ( Fig. 4D ), whereas the adults have a coloration that ranges from pale orange to vermillion red ( Fig. 4C, E ). White spots occur all over the dorsum (from the head to the posterior end) in both juveniles and adults. Depending on the specimen, these white spots can be more or less conspicuous. Right behind the rhinophores and behind the pericardium, the white spots can form a confluent patch. A reticulate pattern produced by the presence of zooxanthellae is usually absent, or at least not easily distinguishable, but when present it is restricted to both sides of the head, just below the rhinophores, as a short branch ( Fig. 4E ), as well as on the insertions of the cerata ( Fig. 4D–E ).

The rhinophores, the oral tentacles, and the foot corners have the same colour as the rest of the body. The rhinophores are perfoliate, bearing 11–14 lamellae with a white apex. They are somewhat shorter than the oral tentacles. The coloration of the tips of the oral tentacles is lighter than the background.

The cerata length varies depending on the size of the animals. Adults have short and thick cerata, and their tips are curved inwards. The cerata of the juveniles are long, thin, and slightly curved inwards ( Fig. 4D ). The cerata are arranged in up to nine arches, leaving a distinct gap between pre- and postpericardial groups. They extend from behind the rhinophores to the posterior end of the body. Each arch contains between five and 26 cerata, decreasing in size towards the foot. The apices of the cerata are translucent white. The cerata are translucent, light brown (juveniles), or bluish dark grey or dark green (adults), with the ramifications of the digestive gland visible through the ceratal wall. All the specimens have white markings all over the ceratal surfaces, although their density and size vary. Only the vermillion red specimens have a vermillion red band on the distal third of the cerata. The anus is cleioproctic and is located within the second right ceratal arch. The genital opening is located within the cerata of the anteriormost group on the right.

Anatomy

The masticatory border is smooth ( Fig. 2E ). The radular formulae are 9 × 0.1.0 ( CPIC 00811, 11 mm), 12 × 0.1.0 ( CASIZ 175735, 6 mm; CASIZ 175737, 13 mm), 16 × 0.1.0 ( CPIC 00810, 12 mm), and 28 × 0.1.0 ( MNCN 15.05/63472, 10 mm). The teeth are progressively smaller towards the posterior region of the radula. The radular teeth are biarched, with 20–55 elongate, moderately broad, and acutely pointed denticles on either side of the triangular central cusp ( Fig. 2F ). The large, composite, and conspicuous oral glands lie dorsolaterally to the buccal bulb. Salivary glands are absent.

The reproductive system is diaulic ( Fig. 3C ). The preampullary duct widens into the elongate ampulla that narrows again before dividing into the oviduct and vas deferens. The conspicuous vas deferens enters the wider proximal portion of the penial sac, which contains the unarmed penial papilla. The oviduct is short and connects to the receptaculum seminis. The remaining portion of the oviduct departs from the base of the receptaculum and enters the female gland. The vagina opens ventral to the penis.

Remarks

MacFarland (1909) erected the species name S. braziliana based on a single preserved specimen collected in Brazil. Despite the fact that the original colour of the holotype had entirely disappeared before it was examined, MacFarland (1909) determined that ‘general differences shown by this specimen in anatomical organization, especially as shown by the mandibles and radula, seem sufficient to authorize its recognition as a member of a species distinct from the European ones already described’. Many authors have rendered S. braziliana as junior synonym or a variety of S. neapolitana ( Engel, 1925; Er. Marcus, 1955, 1957; Just & Edmunds, 1985; Domínguez et al., 2008; García-García et al., 2008). Other authors pointed out the possibility that the western Atlantic Spurilla could be a distinct species from the Mediterranean S. neapolitana ( Forcelli, 2000; Schrödl, 2003). Carmona et al. (2013) recognized the western Atlantic specimens attributed to S. neapolitana as S. braziliana . Our molecular results agree with Carmona et al. (2013) and confirm the presence of this species in the Pacific. Regarding the morphological features of this species, it shows ontogenetic variation in coloration ( Domínguez et al., 2008). Excluding the vermilion red colour forms of S. braziliana , the latter species and S. neapolitana have very similar colour patterns; however, the conspicuous branches of the digestive gland normally visible in S. neapolitana ( Fig. 1B–D, F ) are not easily recognizable in S. braziliana , and if present are restricted to a small branch laterally on the head ( Fig. 4E ), and/or a small and a short branch on the ceratal insertions ( Fig. 4D– E ). Internally, MacFarland (1909) pointed out that the jaws of S. braziliana were noticeably smaller than those of S. neapolitana . After comparing several specimens from São Paulo ( Brazil), Er. Marcus (1955) concluded that the only difference between these two species was the smaller jaws in S. braziliana ; however, we have not been able to confirm this difference. Instead, we have noticed that the denticles of the radular teeth of S. neapolitana are usually thinner compared with those of S. braziliana ( Fig. 2A, E ). Nevertheless, both species have too much intraspecific variation to determine whether this difference can be considered taxonomically significant.

Carmona et al. (2013) indicated that S. braziliana was the only species of Spurilla found in the Pacific Ocean. In this study we have included several specimens collected from Japan, Australia, and the Pacific coast of Costa Rica, confirming the previous hypothesis and conclusively extending the known distribution of S. braziliana into the Pacific Ocean. Pacific specimens seem to have a more limited colour range: mainly orange, with conspicuous white spots over the dorsum and dark greenish grey cerata, with the same marks as the rest of the body ( Fig. 4E ). The ontogenetic variation shown in the Atlantic population has not been found in the Pacific specimens so far.

Vannucci (1952) described the aeolidiid species Eolidina (Spurilla) gabriellae from Brazil. This author observed the animals alive, and illustrated two specimens with a bright orange foot, translucent cerata, and dark brown digestive gland. Vannucci (1952) pointed out that the cerata of this new species were arranged in arches and rows, but no known species of Spurilla has such a ceratal arrangement. Thus, we suspect that this difference is probably caused by the preservation of the specimens. Vannucci (1952) also recognized S. braziliana as the closest relative of S. gabriellae , but based on differences in body size, ceratal arrangement, and radular and jaw morphology, he considered S. gabriellae as distinct species. This species, however, has been regarded as a junior synonym of S. neapolitana ( Schmekel & Portmann, 1982; Domínguez et al., 2008; García-García et al., 2008). We conclude that the morphological differences indicated by Vannucci (1952) are not taxonomically significant, and therefore S. gabriellae is a junior synonym of S. braziliana .

Lin (1992) described the new species Aeolidiella albopunctata based on specimens collected from Hong Kong. Lin (1992) described this species as orange reddish, with orange–yellow oral tentacles, a green– brown digestive gland, and large opaque white spots over the dorsum. According to Lin (1992), A. albopunctata also has small white flecks over the head, the oral tentacles, the rhinophores, and the cerata. Lin (1992) illustrated the living animal, the radular tooth, and the masticatory border. This author pointed out that the cerata of A. albopunctata were arranged in rows and the rhinophores had ‘longitudinal folds above’. Based on the comparison of the external coloration and the radular teeth of A. albopunctata with S. braziliana , and taking into account that the geographical range of S. braziliana includes the Pacific Ocean, we consider A. albopunctata to be a junior synonym of S. braziliana . Differences in the ceratal arrangement and the ornamentation of the rhinophores seem to be caused by the preservation of the specimens, and therefore they are not taxonomically significant.

Figures

Figure 1. Different colour types of Spurilla neapolitana. A, specimen from France, Cap Ferret, Hortense Sud, photo by Marina Poddubetskaia MNCN 15.05/63467; B, specimen from Gulf of Naples, photo by Guido Villani, MNCN 15.05/63466; C, specimen from France, Cap Ferret, photo by Marina Poddubetskaia, CASIZ 192384; D, specimen from France, Cap Ferret, photo by Marina Poddubetskaia, MNCN 15.05/63463; E, specimen from Senegal, photo by Marina Poddubetskaia, MNCN 15.05/63456; F, specimen from Southern Spain, Huelva, El Portil, photo by Sergio García-Gómez, MNCN 15.05/63465.

Figure 2. Scanning electron photographs. A, B, Spurilla neapolitana: A, detailed view of the masticatory border (MNCN 15.05/63463), specimen from France, Cape Ferret, scale bar = 100 μm; B, radular teeth (CASIZ 175756), specimen from Portugal, Algarve, Ponta da Baleeira, scale bar = 20 μm. C, D, Spurilla sargassicola (CASIZ 192385), specimen from Bahamas, Abaco: C, detailed view of the masticatory border, scale bar = 10 μm; D, radular teeth, scale bar = 20 μm. E, F, Spurilla braziliana (CASIZ 175737), specimen from Costa Rica, Pacific Coast, Guanacaste, Punta Carbón; E, detailed view of the masticatory border, scale bar = 10 μm; F, radular teeth, scale bar = 20 μm.

Figure 3. Reproductive system: A, Spurilla neapolitana, specimen from Azores (CASIZ 072582), scale bar = 1 mm; B, Spurilla sargassicola, specimen from the Bahamas (MNCN 15.05/63468), scale bar = 0.5 mm; C, Spurilla braziliana, specimen from Brazil (MNCN 15.05/63471); D, Spurilla onubensis sp. nov., holotype (MNCN 15.05/60081), specimen from Spain, Huelva, scale bar = 0.5 mm; E, Spurilla dupontae. sp. nov., holotype (LACM 3254), specimen from the Bahamas, Stocking Island, scale bar = 1 mm. Abbreviations: am, ampulla; fgm, female gland mass; ps, penial sac; rs, receptaculum seminis; va, vagina; vd, vas deferens.

Figure 4. Photographs of living animals. A, B, different morphotypes of Spurilla sargassicola; A, specimen from the Bahamas, Abaco, photo by Colin Redferns; B, specimen from the Bahamas, Stocking Island, photo by Anne DuPont (CPIC 00816). C–E, different morphotypes of Spurilla braziliana; C, adult from Brazil, photo by Carlos Cunha, MZUSP 103232; D, juvenile from Brazil, photo by Carlos Cunha, MZUSP 103196; E, most common morphotype in the Pacific, specimen from Japan, photo by Rie Nakano.