Pseudione tuberculata Richardson, 1904 (Isopoda: Bopyridae): a parasite of juveniles of the king crabLithodes santolla (Molina, 1782) (Anomura: Lithodidae) in the Magellan Strait, Chile

The parasitic bopyrid isopod Pseudione tuberculata Richardson, 1904 infests the branchial chamber of species of the family Lithodidae found along the southern tip of South America. It was previously known only as a parasite of Neolithodes off the Chonos Archipelago, Chile, as well as Paralomis granulosa (Jacquinot, 1847) and Lithodes santolla (Molina, 1782) from shallow waters of the Beagle Channel, Argentina. This is the first time the parasite is documented in Chile at the Magellan Strait, located about 640 km north of the Beagle Channel, infesting mainly on juveniles of L. santolla (23.0 to 51.6 mm CL in females and from 24.0 to 48.7 mm in males). Prevalence of the parasite in crabs was 27.9% in females and 21.4% in males. Prevalence was higher than those reported in other Chilean crustaceans parasitized by other Pseudione species. Each king crab carried a single pair of P. tuberculata within the branchial chamber on the left side of the carapace. High rates of parasitism of P. tuberculata on juvenile king crabs in this area could occur in shallow water inhabited by Macrocystis pyrifera kelp due to the plant’s effect on the local hydrodynamic conditions, reducing flow and damping waves, providing habitats for several organisms. It is concluded thatP. tuberculata infestingL. santolla at the Magellan strait responds in a similar way when compared with prevalence values from previous studies developed at the Beagle Channel, Argentina, where it has been reported infesting P. granulosa andL. santolla.