New Species of Acanthobothrium (Cestoda: Tetraphyllidea) from Chesapeake Bay, Virginia

Two new species of Acanthobothrium, A. americanum, and A. lineatum, are described from a new host, Dasyatis americana Hildebrand and Schroeder. Acanthobothrium paulum Linton, 1890, is redescribed and considered a valid species. Additional data and corrections are presented in a redescription of A. brevissime Linton, 1908. The locality record for A. floridensis Goldstein, 1964, is extended to Chesapeake Bay, Virginia. A revised key to the species of Acanthobothrium from the Atlantic Coast of North America is presented. Seven species of Acanthobothrium have been described as endemic to elasmobranch fishes from the western north Atlantic and Gulf of Mexico. To date, six of these species, two of which were redescribed by Goldstein (1964), have been considered taxonomically distinct. A study of elasmobranch parasites from the Chesapeake Bay and Atlantic Coast (data to be presented elsewhere) has provided two new species of Acanthobothrium and sufficient material to better define the morphology of A. brevissime Linton, 1908, and to validate A. paulum Linton, 1890. Additional data on the morphology of A. floridensis Goldstein, 1964, were also obtained. MATERIALS AND METHODS Elasmobranchs referred to in this paper were collected from the southern region of Chesapeake Bay, at the Virginia Institute of Marine Science, during the months of June to August, 1967 and 1968. Hosts were collected in trawling nets, or with hook and line. Collecting sites were limited to the lower bay area in that region extending from the mouth of the York River across Hampton Roads to Cape Charles on the Eastern Shore peninsula (37? N, 76020 W). Tetraphyllideans were fixed in situ or removed from the spiral valve, washed in seawater, studied alive, and fixed without pressure in aceto-formol-alcohol either heated or at room temperature. Whole mounts were stained with Ehrlich's acid hematoxylin, cleared in methyl salicylate, and mounted in Permount. Serial sections, stained in Heidenhain's iron hematoxylin and eosin, were studied in frontal, transverse, and sagittal views. Drawings were made with the aid of a camera lucida and microprojector. Descriptive measurements are presented in the manner suggested by Goldstein (1967). All species were compared with available specimens from the USNM Helminth Collection, from the collection of Dr. Robert J. Goldstein, Emory University, and from elasmobranchs collected in the Bay of Naples, Italy. Received for publication 10 December 1968. All measurements are in microns unless otherwise indicated.