Fessisentis necturorum sp. n. (Acanthocephala: Fessisentidae), a parasite of the Gulf Coast waterdog, Necturus beyeri.

Specimens of a previously undescribed species of the genus Fessisentis were taken from the Gulf Coast waterdog, Necturus beyeri beyeri, in southeastern Louisiana. This is the third species of the genus to be described and the first published record of Fessisentis from an amphibian. The new species has a shorter body, smaller proboscis hooks, and a proportionately larger proboscis than F. fessus. The species from Necturus has more longitudinal rows of proboscis hooks each with fewer hooks, relatively smaller male genitalia, and proportionately longer lemnisci than F. vancleavei. In the fall of 1962 and the spring of 1963, a study was made of the Acanthocephala of the Caudata found in Louisiana. This study was based on the collection of 202 specimens of Caudata representing eleven species. Acanthocephalus acutulus Van Cleave, 1931, was found in one of the 67 Plethodon glutinosus examined. Ten of 11 Necturus beyeri beyeri were found infected with an undescribed species of Fessisentis. The following description is based on a series of 75 mature worms (44 females and 31 males).