Lyperosomum intermedium sp. n. (Digenea: Dicrocoeliidae) from the Rice Rat, Oryzomys palustris, from Southeastern Salt Marshes

Abstract

Lyperosomum intermedium is described from the pancreas of the rice rat, Oryzomys palustris, collected from salt marshes in Florida and Georgia. It shows the closest relationship to L. sinuosum Travassos, 1917, from which it differs in body shape and proportions, size and location of the acetabulum, and the size and distribution of the vitellaria. A new dicrocoeliid trematode was found in the pancreas of rice rats, Oryzomys palustris (Harlan), from salt marsh habitats in Georgia and Florida. Twenty-eight of 72 rice rats from the vicinity of Cedar Key, Florida, were infected with one to 150 worms (mean 17). Five of six rice rats from Sapelo Island, Georgia, examined by Richard W. Heard were infected with two to 51 worms (mean 18). Over 100 rice rats obtained from freshwater marshes in Florida were not infected. For this undescribed worm the name Lyperosomum intermedium sp. n. is proposed. The flukes were killed in hot saline under slight coverglass pressure, fixed in Roudabush's fluid, and stained with Harris' hematoxylin. The figures were drawn with the aid of a camera lucida and measurements are given