Metoliophilus uvaticus gen. et sp. n. (Lecithodendriidae: Metoliophilinae subf. n.) from the Dipper, Cinclus mexicanus, in Oregon

Abstract

Metoliophilus uvaticus is described as a new genus and species of intestinal trematode, collected from adult and nestling dippers in Oregon. It is characterized by a covering of integumental scales; ceca of moderate length; cirrus sac mainly anterior and to the left of acetabulum, directed posteriad; genital pores separate but adjacent, submedian, near posterior margin of acetabulum; ovary deeply lobed, between intestinal fork and testes; and tubular excretory vesicle. A new subfamily is erected for this genus. Egg-producing adults were obtained in chicks 5 days after feeding metacercarial cysts from nymphs of the stonefly, Acroneuria pacifica (Banks). After 10 days adult flukes were found in the muscular layer of the bird's intestinal wall. Most nymphs of the large stonefly, Acroneuria pacifica (Banks), collected in the Metolius River near Camp Sherman, Deschutes County, on the eastern slope of the Cascade Mountains in central Oregon, were found to contain encysted metacercariae. When fed to day-old chicks of Gallus gallus domesticus, these developed in the small intestine into mature trematodes identified as a new species, genus, and subfamily of the Lecithodendriidae. One specimen of this fluke with few eggs was found in a dipper from the same locality; a second specimen without eggs was taken from a dipper collected from Nehalem, near the Oregon coast; and 14 large individuals with numerous eggs were found in one of four nestling dippers collected near the Nehalem River, Clatsop County, about 20 miles upstream from Nehalem. Dippers from streams along the Columbia River Gorge, Multnomah County, were negative for this fluke.