On a Copepoda Nicothoid parasitic on the cumacean Diastylis fabrizoi n. sp. from the southwestern Atlantic Ocean.

ALBERICO, N.A.; ARIAS, M.G.; ROCCATAGLIATA, D.

Coquimbo, Chile

Congreso; The Crustacean Society Mid-Year Meeting; 2007

Universidad Católica del Norte

Nicothoids have been reported infesting either the branchial chambers or the brood-pouch of cumaceans. Of the 1773 specimens of Diastylis fabrizioi n. sp. recently collected in the southwestern Atlantic Ocean, 2.6 % was found to be infested by a nicothoid of the genus Homoeoscelis. The infested cumaceans were easily detected because their carapaces were considerably swollen on the side containing the parasites, and/or the parasites were perceptible through the hosts’ partially translucent cuticle. Of the 46 parasitized cumaceans gathered, 17 were adult females (with fully developed oostegites), 22 preparatory females, 2 subadult males and 5 juveniles. No infested adult males were observed. Ten out of the 17 infested adult females contained mancas or eggs in different stages of development in their brood-pouches, suggesting that the parasite does not affect the reproductive potential of the host. Inside the gill chambers of the hosts adult females and males, copepodids and ovisacs were found. The parasite occurs nearly equally in the right and left gill chambers, and no double infestations were observed. Thirty-eight out of the 44 female parasites found were accompanied by a male (rarely 2). This is the first time the genus Homoeoscelis is recorded from the Southern Hemisphere. This research was partially supported by the ANPCyT (PICT 02-11180) and the Argentine Scientific Research Council (CONICET).