Philophthalmus hegeneri sp. n., an Ocular Trematode from Birds

Abstract

Philophthalmus hegeneri sp. n. is described from adults reared from megalurous cercariae developing in the marine snail, Batillaria minima (Gmelin, found infected at numerous shore localities along the Gulf of Mexico from Dunedin to Key West, Florida. Metacercariae in flask-shaped cysts were infective orally and ocularly to various experimental birds including domestic chickens and pigeons, Mute Swan (Cygnus olor), Western Gull (Larus occidentalis), and the Southern Chachalaca (Ortalis ruficauda). Natural avian hosts include the Royal Tern (Thalasseus maximus), Yellow-crowned Night Heron (Nyctanassa violacea), Laughing Gull (Larus atricilla), and the Willet (Catoptrophorus semipalmatus). The genus Ophthalmotrema is considered a synonym of Philophthalmus. This is the first time a marine gastropod has been implicated in the biology of any member of this genus. A marine-acquired species of Philophthalmus which reached maturity under the nictitating membrane of a variety of experimental avian hosts has been mentioned by Penner and Fried (1961), Fried and Penner (1961), and Fried (1962a, b, c). The adult flukes were noted as related to the lucipetus group of 4 of the 23 species previously described in having follicular rather than tubular vitellaria. These were P. lucipetus, P. lachrymosus, P. offlexorius, and P. skriabini. Because our material from both experimental and natural infections differs from all previously described species of Philophthalmus, it is necessary to report the species as new. All measurements are in millimeters. Philophthalmus hegeneri sp. n.