Periclimenes amethysteus

The retainer shrimp Periclimenes amethysteus belongs to the family Palaemonidae, belonging to the order of the decapods. It is a species that usually lives at shallow depths (up to 15-20 meters generally), in relatively rocky areas where they maintain a symbiotic relationship with various species of cnidarians such as those of the genera Aiptasia, Anemonia, Condylactis and Cribinopsis. Among the tentacles of these cnidarians, Periclimenes amethysteus finds shelter and protection from predators, keeping in return the cnidarian dewormed and neat. It is also possible to observe specimens of this species deworming certain fish at cleaning points. Their distribution range covers the waters of the Mediterranean Sea, especially in the western region, although they are also present in the waters of the Adriatic Sea.

The body of Periclimenes amethysteus can reach up to 3 cm in total length. The body is robust and together with the rostrum, both are slightly compressed laterally. On the rostrum there is a central denticulated notch that runs along the entire length of the elongated rostrum. On the lower part of the body there are several pairs of legs, of which the first two pairs are equipped with elongated claws. The body of Periclimenes amethysteus is translucent with some whitish/beige spots with a white border and numerous pink stitches inside. On the rostrum there is a large triangular spot starting from the posterior part of the rostrum and pointing forward until it reaches the base of the rostrum. In the second segment of their abdomen they have in the dorsal part an elongated transverse spot. After this we find in the third segment another heart-shaped spot (rarely forms a V), and also three other smaller rounded spots in the fourth to sixth segments. In sexually mature females, there are also rounded spots on the sides of the first 4 segments of the abdomen. The legs usually have alternating white and bluish bands, while the claws have alternating white stripes with transverse stripes that may be lilac, pink or sometimes bluish.

The diet of Periclimenes amethysteus, as expected from symbiotic behavior, is opportunistic and omnivorous, finding among its food various decomposing debris, algae or any organic matter they find.

The breeding season of Periclimenes amethysteus is usually during the month of August, when the female specimens will carry the previously fertilized eggs under their abdomen.