Redescription of Camallanus cotti Fujita, 1927 (Nematoda: Camallanidae) from Hawai'i

The freshwater fish parasite Camallanus cotti Fujita, 1927 (Nematoda: Camallanidae) is redescribed from the guppy Poecilia reticulata (Poeciliidae). We confirm previous reports of its occurrence in other introduced poeciliids in Hawai'i, in 4 species of native Hawaiian gobioid stream fishes, and in an elasmobranch, an aquarium-reared stingray Potamotrygon sp. (Dasyatididae) from Hawai'i. Because the source localities of introduced freshwater fish parasites may be far removed geographically from communities that they have invaded, especially oceanic archipelagos (such as Hawai'i), we believe that research on these exotic parasites must be based upon critical taxonomic evaluations. Our redescription of C. cotti serves as a foundation upon which ecological studies of this parasite, performed in conjunction with conservation efforts for native Hawai'ian stream fishes, will be based.