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342 NEW RECORDS OF APLYSIA DACTYLOMELA

Introduction Mediterranean Sea (see Fig. 2). The first occurrence was
photographed in Cap d’en Font (39º49’35’’N-4º12’20’’E;
th
Anaspidean heterobranch molluscs are widely distributed Minorca, Balearic Islands, Spain), on the 25 June 2016 by
worldwide, mostly found in shallow temperate and tropical the underwater photographer Joop Werson. The individual
waters (Carefoot, 1987). The spotted sea hare Aplysia measured 13 cm (Fig. 1A) and was found at 15 m depth.
dactylomela Rang, 1828, has been described from the The second occurrence was photographed in Cala Secains
Atlantic region, by externally displaying a yellowish (41º46’46’’N-3º2’46’’E; Sant Feliu de Guíxols, Catalonia,
colouration with large, black rings distributed all over the Spain), on the 20 th June 2016 by the free-diver and
body (Rang, 1828). This species was considered to be underwater photographer Xavier Salvador. The individual
distributed in both sides of the Atlantic (i.e. amphi-Atlantic) measured 12 cm (Fig. 1B) and was found at 1 m depth.
and in the Indo-Pacific Oceans. Nonetheless, the species is Finally, the third record was found in Cala Es Caials
presently divided into two sibling species based on both (42º17’7’’N-3º17’ 47’’E; Cadaqués, Catalonia, Spain), on
th
molecular and morphological data (Alexander & Valdés, the 18 August 2016 by the biologist Àlex Bartolí. The
2013): A. dactylomela and A. argus Rüppell & Leuckart, individual measured around 15 cm (Fig. 1C) and was found
1830, from the Atlantic and Indo-Pacific, respectively. The at 4 m depth.
first record of A. dactylomela in the Mediterranean Sea was
in the island of Lampedusa (central Mediterranean) in 2002 Description
(Trainito, 2003). Since then, a plethora of new records The three specimens photographed were beige to yellowish
popped out in the eastern and central Mediterranean basin, in colour, with black rings and a network of black lines all
including Israel, Lebanon, Syria, Cyprus, Turkey, Greece, over the body (Fig. 1A-C). The parapodial lobes were high,
Croatia, Malta, and Italy (Schembri, 2008; Yokes, 2008; joined low down near the posterior foot. The cephalic
Crocetta & Galil, 2012; Crocetta et al., 2013; Valdés et al., tentacles and rhinophores were broad and blunt. The
2013; Katsanevakis et al., 2014). Although this fast invader animals secreted a purple defensive ink when molested.
was firstly proposed to come from the Red Sea via the Suez
Canal (i.e. Erythrean migration; Crocetta & Galil, 2012), Ecology
later studies showing the atypical sequence of colonization
of A. dactylomela and DNA data recover this species as a The three specimens were found at shallow waters on a
colonizer from the Atlantic via the Strait of Gibraltar photophilic, seaweed community: dominated by the red
(Valdés et al., 2013). Nonetheless, its Mediterranean alga Laurencia obtusa (Hudson) J.V.Lamouroux, 1813
introduction vector is not yet established with certainty, and (Rhodomelaceae) and the brown alga Dictyota cf.
therefore A. dactylomela has been cautiously considered as dichotoma (Dictyotaceae), for specimen 1 (Fig. 1A);
a cryptogenic species (Mannino et al., 2017). dominated by the red alga Laurencia obtusa and the brown
The main aim of this study is to present the first records algae Cystosseira compressa (Esper) Gerloff &
of A. dactylomela in the Spanish coast (western Nizamuddin, 1975 (Sargassaceae) and Padina pavonica
Mediterranean Sea) and discuss about the causes of such (Linnaeus) Thivy, 1960 (Dictyotaceae), for specimen 2
successful colonization in this area. (Fig. 1B); and dominated by Cystoseira mediterranea,
Sauvageau, 1912, P. pavonica, and the seagrass Posidonia
Material and Methods oceanica (Linnaeus) Delile, 1813, for specimen 3 (Fig. 1C).

Three new records were obtained from the online database Discussion
of GROC (Catalan Opisthobranch Research Group;
http://www.opistobranquis.org/). All records were uploaded Three new records of the spotted sea hare A. dactylomela in
by certified divers currently involved in the association.
the western Mediterranean Sea are reported in this study.
Our data together with the obsarvations around Egadi
Systematics Islands (Mannino et al., 2014) and the single record in a
port in Monaco (Karachle et al., 2016) clearly reflect a fast
Anaspidea Fischer, 1883 and progressive colonization of the species in the western
Aplysiidae Lamarck, 1809 Mediterranean Sea (Fig. 2). Moreover, we also recovered
Aplysia dactylomela Rang, 1828 this species in unperturbed ecosystems, thus reinforcing the
(Fig. 1A-B)
ecological success of A. dactylomela for dispersion and
habitat colonization.
Material examined
There are several factors that promote the broad
Three new specimens were recorded in the western dispersal potential of A. dactylomela into the