The Life Histories and Classification of Two Allocreadiid-Like Plagiorchids from Fish, Macroderoides typicus (Winfield) and Alloglossidium corti (Lamont)

Abstract

In examining snails collected in the region of the University of Michigan Biological Station, located on Douglas Lake in the northern part of the Southern Peninsula of Michigan, nineteen species of Xiphidiocercariae were found. These cercariae were placed with a wide variety of organisms in order to determine their second intermediate hosts. The metacercariae which developed were then fed to 24 species of animals, representing all classes of vertebrates. Two of the species of these cercariae were in this way proved experimentally to be those of Macroderoides typicus and Alloglossidium corti. The details of the experimental work and the morphology of the stages of these two species are discussed in the present paper. The cercariae of both species were found developing in small sporocysts in Heliosoma trivolvis and H. campanulata. The incidence of infection with the cercaria of M. typicus was relatively high and infected snails were collected from several areas in Douglas Lake, Burt Lake, and Mullet Lake. The cercariae were found experimentally to penetrate into several possible intermediate hosts but tadpoles were used in the infection of the definitive host. Experimentally infected tadpoles were fed to Amia calva and large numbers of trematodes, identified as Macroderoides typicus (Winfield), were recovered from the intestine. The incidence of infection with the cercaria of A. corti was relatively high in the snails collected in Munro Lake and lower in those from several areas of Douglas Lake. It was experimentally demonstrated that this cercaria would penetrate into and encyst in dragonfly and mayfly nymphs. The metacercariae from these hosts were fed to small, trematode-free bullheads and adult flukes, identified as A. corti (Lamont), were recovered from the small intestine.