NOTES AND NEWS

MACROPODIA LONGIROSTRIS AND LATREILLIA ELEGANS (DECAPODA, BRACHYURA) CLIMBING ON MEDITERRANEAN PENNATULIDAE (, ): A PRELIMINARY NOTE

BY

ERIKAM.D.PORPORATO1), FRANCESCA DE DOMENICO, M. CRISTINA MANGANO and NUNZIACARLA SPANÒ Dipartimento di Biologia Animale ed Ecologia Marina, Università degli Studi di Messina, Viale F. Stagno D’Alcontres, 31, I-98166, Messina, Italy

INTRODUCTION Associations between octocorals and other invertebrates are well known; in par- ticular relationships involving Crustacea Decapoda are not unusual and have al- ready been reported from tropical and temperate areas in intertidal and subtidal regimes (e.g., Bruce, 1969, 1976; Patton, 1976; Reed et al., 1982; Wirtz, 1997; Jonsson et al., 2001; Khan et al., 2004). The Pennatulidae are octocorals com- monly known as sea pens and represent a significant component of the benthic sessile megafauna from nearshore to the abyss (Lopez-Gonzalez et al., 2001 and references therein; Tyler, 2003). However, only a few studies have documented epibiosis phenomena involving Pennatulidae. Associations with decapods of the Porcellanella in the Red Sea and the Sea of Japan have been widely reported (Jones, 1959; Sankarankutty, 1961; Johnson, 1964). This note reports the first documented record of two possible associations involving the Mediterranean sea pens, Pteroeides spinosum (Ellis, 1764) and phosphorea (Linnaeus, 1758) with the crabs Macropodia longirostris (Fabricius, 1775) and Latreillia elegans (Roux, 1830), respectively.

MATERIAL AND METHODS The organisms were collected during 2008 and 2009 on soft bottoms, from depths of 25 to 35 metres, off Giardini Naxos (Messina), in the Ionian Sea (central Mediterranean Sea). The organisms were mainly observed in situ and manually

1) Corresponding author; Fax: +39.0906765526; e-mail: [email protected] © Koninklijke Brill NV, Leiden, 2011 Crustaceana 84 (14): 1777-1780 Also available online: www.brill.nl/cr DOI:10.1163/156854011X612884 1778 NOTES AND NEWS sampled by SCUBA divers. Additionally, some records were collected by trammel net during experimental fishing surveys carried out in the southern Tyrrhenian Sea and in particular off Capo d’Orlando (Messina) between 57 and 59 metres depth. The sea pens were identified according to Williams (1995) and their main mor- phometric features were measured: total length, rachis and peduncle length, and the peduncle diameter. Decapod crustaceans were identified according to Zariquiey Alvarez (1968) and Falciai & Minervini (1992), and their main morphometric mea- surements were recorded: length and width of the carapace.

RESULTS A total of 4 combinations of Macropodia longirostris/Pteroeides spinosum were observed in situ and sampled. The specimens of M. longirostris (3 males and 1 female), varying in carapace length from 16 to 18 mm, were climbing on the distal leaves of P. spinosum showing a colour pattern similar to that of the host. Besides, 2 combinations of Latreillia elegans/Pennatula phosphorea were also recorded. The L. elegans specimens, both females, measured, respectively, 9 and 10 mm in carapace length. Each of them was observed climbing on the distal body portion of a P. phosphorea and showed a colour similarity with its host. Additionally, during various experimental fishing surveys, M. longirostris in combination with P. spinosum (3 records) and, L. elegans with P. phosphorea (1 record) were collected. The crabs were observed wedged in the sea pens and all showed strong colour similarity to them. The details of the records, together with the main morphometric features measured for each collected specimen, are summarized in table I.

DISCUSSION AND CONCLUSION Associations involving crustaceans and other invertebrates are various and well known (e.g., Gore et al., 1978; Wirtz & Diesel, 1983; Thiel & Baeza, 2001; Baeza & Thiel, 2003; Valdivia & Stotz, 2006; De Domenico et al., 2010). The crustacean can take advantage from its host in many ways: as a useful substratum, especially where hard bottoms are lacking; providing shelter, and protection from predators; as well as a potential food source. Nevertheless, the relationship that might occur between Macropodia longirostris and Latreillia elegans and their hosts is not clear. These crabs, climbing on their hosts, could improve protection against visual predators because of their colour similarity; they could utilize their host for attachment and elevation over sediments taking advantage also during their own search for prey.