Members of the genus Platyamoeba are among the most common of the free-living brackish and marine amoebae; yet, to date only twelve species have been documented in the literature and only a limited number of habitats have been sampled globally. During the course of a systematic survey of salt-marsh amoebae along the east coast of the United States, a new species of Platyamoeba was discovered in sediment samples obtained from a salt marsh at Assateague Island, VA. The species can be distinguished from all other described species within the genus by the presence of a nucleus with a single parietal nucleolus and a floating form with long tapering pseudopods. Its shape varies from flabellate to spatulate as described for species of Platyamoeba and Vannella. The fine structure of the glycocalyx, however, is characteristic of Platyamoeba.