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Loxothylacus panopaei
Image courtesy of Monaca Noble, SERC. Parasite Loxothylacus panopaei infecting a White-fingered Mud Crab (Rhithropanopeus harrisii)
Loxothylacus panopaei
Taxonomic Group: Crustaceans-Barnacles


The parasitic barnacle, Loxothylacus panopaei, was first described in 1884 from specimens on the panopeid crab Panopeus lacustris from Tampa, Florida. Its native range extends through the Gulf of Mexico, into the Caribbean and Venezuela, and northward on the Atlantic coast to Cape Canaveral, Florida. Loxothylacus panopaei is introduced along the Eastern United States coast and was first found in Chesapeake Bay in 1964. Since then it has expanded northward to Long Island Sound, and southward to just north of Cape Canaveral, almost reaching the northern limit of native populations. The host range of L. panopaei is considered to include at least nine species of panopeid crabs. The effects on individual crabs are complex and diverse. Loxothylacus panopaei extensively modifies its hosts physiology and behavior, and castrates both male and female crabs making them unable to reproduce.

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Fofonoff PW, Ruiz GM, Steves B, Simkanin C, & Carlton JT (2018)
National Exotic Marine and Estuarine Species Information System.
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Marine Invasions Lab
Smithsonian Environmental Research Center

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