Living on Antedon Mediterranea (Echinodermata, Crinoidea)

YOUNG SPECIMENS OF MUNIDA INTERMEDIA (DECAPODA, ANOMURA) LIVING ON ANTEDON MEDITERRANEA (ECHINODERMATA, CRINOIDEA)

FRANCESCA DE DOMENICO1), M. CRISTINA MANGANO, ERIKA M. D. PORPORATO and NUNZIACARLA SPANÒ Dipartimento di Biologia Animale ed Ecologia Marina, Università degli Studi di Messina, Salita Sperone, 31, I-98166, Messina, Italy

ABSTRACT

A hitherto undescribed association between the comatulid, Antedon mediterranea and the galatheid crab, Munida intermedia, from the Tyrrhenian Sea (Mediterranean Sea), is herein reported. Three pairs of Antedon/Munida were sampled on muddy bottoms at a depth ranging from 10 to 95 m. The crabs collected were too small to establish their sex, and two of them were smaller than previously recorded. The specimens of M. intermedia were found on the external side of the arm base of the host and showed a cryptic coloration pattern. The relationship between A. mediterranea and young M. intermedia is not yet clear. The ﬁrst seems to be a passive partner, while the latter probably takes advantage of its position on the crinoid’s arm. The crab may ﬁnd protection and shelter, and it may capture planktonic matter or larger living prey.

RIASSUNTO

In questa nota si riporta la segnalazione della associazione, ad oggi mai descritta, tra il comatulide Antedon mediterranea e il granchio galateide Munida intermedia, nel Mar Tirreno (Mar Mediterraneo). Sono state collezionate tre coppie di Antedon/Munida provenienti da fondi mobili tra 10 e 95 metri di profondità. I granchi sono risultati troppo piccoli per poterne determinare il sesso e due di essi sono risultati i più piccoli mai registrati per questa specie. Gli esemplari di M. intermedia sono stati rinvenuti alla base del braccio dell’ospite, sulla parte esterna e presentavano un pattern di colorazione simile al crinoide. Le relazioni che possono intercorrere tra A. mediterranea egiovani di M. intermedia non sono ancora chiare. Quest’ultimo probabilmente trae vantaggio dalla sua posizione sul braccio del crinoide, che invece sembrerebbe un partner passivo. Il granchio può trovare protezione e riparo e può catturare materiale organico sospeso o prede vive di maggiori dimensioni.

1) Corresponding author; Fax: +39.0906765526; e-mail: [email protected] © Koninklijke Brill NV, Leiden, 2010 Crustaceana 83 (2): 215-221 Also available online: www.brill.nl/cr DOI:10.1163/001121609X12530988607597 216 FRANCESCA DE DOMENICO ET AL.

INTRODUCTION Symbiotic relationships involving echinoderms are well known, not only from the tropical Indo-West Pacific region (Fishelson, 1974; Bruce, 1976, 1982; Ng & Lim, 1990; VandenSpiegel et al., 1998 and references therein; Kirinciˇ c,´ 2006). There is a variety of reasons for these associations, such as physical protection of one species by another, exploitation of a new substrate provided by the host, and the alternative trophic pathways provided by the different habitats of the echinoderm species (Coppard & Campbell, 2004). In particular, associations relating to crinoids are well recognized. For example, tropical echinoderms are considered the centre of complex and multispecies series of interactions among different invertebrates that inhabit/parasitize them (Fishelson, 1974; Huang et al., 2005). It is not unusual to find decapod crustaceans associated with comatulids that can live upon the crinoid’s calyx (Bruce, 1976; VandenSpiegel, 1998), hide among the pinnules of the host, or along its arms (Fishelson, 1974). This study deals with a newly discovered association between the comatulid, Antedon mediterranea (Lamarck, 1918) and the galatheid crab, Munida intermedia A. Milne-Edwards & Bouvier, 1899, in the Southern Tyrrhenian Sea (Mediter- ranean Sea). Though both are typical Mediterranean species, this is the first record of their association. The comatulid A. mediterranea is, in fact, the most common Mediterranean crinoid, living on both hard and muddy bottoms, and represent- ing an important component of infra- and sublittoral sciaphilic communities (Tor- tonese, 1965). The squat-lobster, M. intermedia is very common all over Mediter- ranean muddy bottoms in a wide bathymetric range (Abelló, 1988). It frequently dominates the crustacean fraction of the discards of bottom trawlers (Froglia & Gramitto, 1995; Abelló et al., 1988; Gramitto & Froglia, 1998).

MATERIAL AND METHODS Ten specimens of Antedon mediterranea and five of Munida intermedia were sampled during three different surveys carried out in the Southern Tyrrhenian Sea, along the Sicilian and Calabrian coasts (Mediterranean Sea). The organisms were collected from July to October 2008 at depths ranging from 10 to 95 meters at three different locations (fig. 1): in the Termini Imerese Gulf, near Palermo, by trawl net (MEDITS project); in the Gioia Tauro Gulf, using a modified Van Veen grab of 70 l (MAP Project); off the Capo d’Orlando coast (Messina), employing a trammel net (La Torre Project) (table I). The organisms collected, previously sorted, were preserved in 70% ethanol. The crinoids were, subsequently, identified relying on Koehler (1927), Tortonese (1965), Zavodnik (2003), and De Domenico et al. (2009) and were measured in terms of centrodorsal diameter. M. intermedia