Studies on the Life Histories of Maritrema obstipum (Van Cleave and Mueller, 1932) and Levinseniella amnicolae n. sp. (Trematoda: Microphallidae)

Abstract

In Barrett's Pond, near Cold Spring on Hudson, New York, two species of minute xiphidiocercariae were found in Amnicola pilsbryi Walker, 1906, and their life histories subsequently traced. These cercariae proved to be larvae of the microphallid trematodes indicated in the title. Both cercariae were experimentally found to penetrate the aquatic isopod, Asellus communis Say, 1818, and reach sexual maturity in a variety of birds and mammals. Natural infections of larval and adult stages of both species were also identified. With few exceptions, members of the family MICROPHALLIDAE are parasitic in aquatic birds, particularly those of the seashore. Several species have been described from fishes, but of these, Gynaecotyla adunca has been shown naturally and experimentally to infect various shore birds, and Microphallus opacus to reach sexual maturity in the raccoon, opossum, turtles, and snakes. The majority of life history studies previously reported have indicated marine molluscan and crustacean intermediate hosts. The present study is one of the first reports of fresh water snails as intermediate hosts in the family. The brief paper of Carrere (1936) is the only account of brackish water intermediate hosts. The present specimens of Maritrema closely resemble Maritrema obstipum (Van Cleave and Mueller, 1932), a species based on a single immature worm from the intestine of the rock bass, Ambloplites. Accordingly, comparison was made with the type specimen, obtained from the U. S. National Museum through the courtesy of Dr. E. W. Price. In most of its dimensions it fits into the range of size determined for the present material, but differs in the following features: the greater length, coiling, and smaller diameter of the ductus ejaculatorius; the smaller diameter of the male papilla; and the larger size of the pharynx. These differences are regarded as insufficient to justify recognition of a new species, and the present specimens are therefore tentatively allocated to Maritrema obstipum. The species of Levinseniella studied proved to be new.