A Review of Host Specificity in Tanaorhamphus longirostris (Acanthocephala: Neoechinorhynchidae)

Of 13 species of fish recorded as hosts for the acanthocephalan, Tanaorhamphus longirostris (Van Cleave 1913), only two regularly contain mature worms. These are the gizzard shad (Dorosoma cepedianum (Lesueur)) and the threadfin shad (D. petenense (Giinther)). To date, only one species of intermediate host, the calanoid copepod, Diaptomus pallidus Herrick, has been reported. In Caesar Creek Lake, Ohio, where the parasite is known to exist, of 15 species of planktonic crustaceans examined, only D. pallidus contained the cystacanth of T. longirostris. Comparison of geographic distributions and ecological and behavioral factors suggests that this association (i.e. worm, shad, copepod) represents a relatively new or developing relationship that may not yet fit closely the classical requirements for strict host specificity. Feeding behavior and host gut morphology may be the combination of factors that provides for reproductive success of T. longirostris in shad. OHIO J. SCI. 87 (3): 61-66, 1987