Systematics, Distributional Ecology, and Some Host-Parasite Relationships of Uhlorchestia uhleri (Shoemaker) and U. spartinophila, New Species (Crustacea: Amphipoda), Endemic to Salt Marshes of the Atlantic Coast of North America

ABSTRACT The palustral talitrid amphipod genus Uhlorchestia Bousfield, 1984, is endemic to marshes of Spartina of the North American Atlantic coast. On the basis of newly developed characters and phyletically ordered character states, Uhlorchestia spartinophila, new species, and Uhlorchestia uhleri (Shoemaker, 1930) are herewith described and figured. Uhlorchestia uhleri is a larger, more southerly species (North Carolina to Texas), confined to the upper, more brackish portions of coastal marshes, mainly in association with Spartina patens. Its character states are, in balance, slightly more plesiomorphic than those of the smaller, more northerly U. spartinophila, new species (central Maine to northeastern Florida) that dominates the middle to lower, more saline regions of salt marshes, mainly in association with Spartina alterniflora. Both talitrid species are often parasitized by protozoans and larval helminths. Parasitized individuals are characterized by changes in color and behaviour.