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ASTROPECTEN OF THE MEDITERRANEAN SEA Starfishes of genus Astropecten live on mobile seabed (sandy, muddy or gravel seabed) and they remain largely buried under sediment during the day. During the late afternoon and the night starfishes go out to hunt mainly bivalve molluscs, which are their favourite preys. In turn they are preyed by large molluscs such Charonia lampas, Charonia variegata and probably Tonna galea. In the Mediterranean area there are six species belonging to the genus Astropecten: - Astropecten aranciacus (Linnaeus, 1758) - Astropecten jonstoni (Delle Chiaje, 1827) - Astropecten irregularis (Pennant, 1777) - Astropecten spinulosus (Philippi, 1837) - Astropecten bispinosus (Otto, 1823) - Astropecten platyacanthus (Philippi, 1837) These sea stars are similar one to each other and it can be difficult to determine with certainty the species only from a photograph. To have a certain determination, in some cases, animals should be analyzed in the laboratory or using genetic testing, but often it isn’t possible. In order to determine the species, with a reasonable margin of error, it’s necessary to observe the appearance of the animal, in particular, based on some typical features described by principal authors that have analyzed over the years a large number of specimens in the laboratory. All of the following are described the main elements found in thousands of specimens encountered and photographed in the Mediterranean Sea (Italy: Trieste, Sardinia; France: Corse; Croatia: Rab, Cres, Krk, Hvar; Greece: Lefkada, Karpathos, Milos, Naxos, Paros, Antiparos, Koufonissi, Kato Koufonissi, Donoussa, Mykonos, Thira, Creta, Limnos; Spain: Menorca) and the features described by authors such as Enrico Tortonese, Rene Koehler, Emil Von Edler Marenzellerin necessary to make identifications. For species such as Astropecten aranciacus, Astropecten jonstoni, Astropecten irregularis and , Astropecten spinulosus usually it is an easy task, but for more complex species such as Astropecten bispinosus and especially Astropecten platyacanthus it needs a more thorough analysis. The main elements, to determine the various species from photo, are: the appearance of the dorsal marginal plates and spines, the size, the shape of disc and arms. For a good identification by sea photo is important to take a complete picture of all the subject, a picture of the detail of the marginal plates and to measure as precisely as possible the diameter of the sea star. All this can be done without touching, turn in, or disturb the animal. The main elements of starfish genus Astropecten: 1


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