Fessisentis
Fessisentis is a genus of parasitic spiny-headed (or thorny-headed) worms. It is the only genus in the family Fessisentidae. This genus contains six species that are distributed across the Eastern continental United States as far west as Oklahoma and Wisconsin. These worms parasitize salamanders and fish. Taxonomy and description Species of Fessisentis are highly variable and there are few recognized diagnostic characteristics. Classification depends upon comparison of many characters, the ranges of which frequently overlap at the extremes however lemniscal length is a relatively consistent difference among species. Species There are six species in the genus Fessisentis. Fessisentis acutulus (Van Cleave, 1931) F. acutulus has been found parasitizing the Eastern newt, (Notophthalmus viridescens). F. acutulus has been rarely collected since its original description. It has been found in North Carolina salamanders Ambystoma opacum, Desmognathus fuscus, Plethodon glutinosus, and Notophthalmus viridescens by Rankin in 1938, from the Northern slimy salamander (Plethodon glutinosus) in Louisiana by Nickol in 1969 and from the Hellbender (Cryptobranchus alleganiensis) in Missouri by Dyer and Brandon in 1973. Fessisentis fessus Van Cleve, 1931 F. fessus has been found infecting the Lesser siren (Siren intermedia) from Union County, Illinois and the Freshwater drum (Aplodinotus grunniens) in Money, Mississippi