DAO 31:65-71 (1997)  -  doi:10.3354/dao031065

Livoneca sp. (Flabellifera: Cymothoidae), an isopod parasite in the oral and branchial cavities of the Red Sea silverside Atherinomorus lacunosus (Perciformes, Atherinidae)

Angelo Colorni1,*, Jean-Paul Trilles2, Daniel Golani3

1Israel Oceanographic and Limnological Research, National Center for Mariculture, Eilat 88112, Israel
2Laboratoire d'Écophysiologie des Invertébrés, C.C. 092, Université de Montpellier 2, Place Eugène Bataillon, F-34095 Montpellier Cedex 05, France
3Department of Evolution, Systematics and Ecology, The Hebrew University of Jerusalem, Jerusalem 91904, Israel

A parasitic isopod, Livoneca sp. (Flabellifera: Cymothoidae), is reported from silverside Atherinomorus lacunosus in the Red Sea. The female isopod settles on the fish's tongue. Presence of a gravid female in the oral cavity was always associated with that of a single, smaller male occupying the gill chamber. Approximately 3.6% of the fish examined were found to be infested with the parasites in the adult phase. Histological damage to the fish appears limited to the gill rakers and filaments upon which the female isopod rests her abdomen and tail. The gill filaments above the site in which the male settles become similarly dystrophic. However, none of the fish infested displayed any obvious sign of respiratory distress or stunted growth. The chitinous segments of the isopod armoring, imbricated like roof tiles with their free margin directed backward, seem perfectly adapted to performing the same gripping function as the fish's tongue. This host-parasite relationship appears to be species-specific and has all the characteristics of an evolutionary process of adaptive strategy, as it clearly enables the host to maintain its feeding ability while the parasite grows to sexual maturity.


Cymothoid · Isopod · Parasite · Livoneca · Silverside · Atherinomorus lacunosus · Atherinidae · Red Sea


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