A Revision of Some Trypanorhynchs from the Western North Atlantic Described by Edwin Linton

Abstract

The species of trypanorhynchs described by Edwin Linton (18910) as Rhynchobothrium tumidulum and Rhynchobothrium hispidum are assigned to the genus Prochristianella Dollfus 1946. Prochristianella penaei Kruse 1959 is a synonym of R. hispidum. Rhynchobothrium brevispine Linton 1897 is placed in the genus Mecistobothrium Heinz and Dailey 1974. The species Prochristianella hispida (Linton 1890) comb. n., P. tumidula (Linton 1890) comb. n., and Mecistobothrium brevispine (Linton 1897) comb. n. are redescribed. Adults of Parachristianella monomegacantha Kruse 1959 from Dasyatis americana Hildebrand and Schroeder, taken in Chesapeake Bay, Virginia, are described. Edwin Linton, in a series of works spanning about half a century, described many cestodes from fishes in the western North Atlantic. Among his descriptions are numerous trypanorhynchs, many of which he believed to be speies of Rhynchobothrium Rudolphi 1819. Dollfus (1929) examined this genus and found it to consist of a complex of genera, thereby rejecting it. He subsequently made several contributions (1942, 1946) correcting the taxonomy of some of Linton's species but the status of many more remains uncertain and requires clarification. Nine of Linton's species were reclassified by Dollfus and the clarification of four more species of Rhynchobothrium in this paper brings to 13 the number correctly identified to date. A list of those species (Table I), their new combinations, and authors, is appended. In the present paper Prochristianella hispida (Linton 1890) comb. n., Prochristianella tumidula (Linton 1890) comb. n., and Mecistobothrium brevispine (Linton 1897) comb. n., are redescribed. Rhynchobothrium agile Linton 1897 is a synonym of M. brevispine (Linton 1897) comb. n. MATERIALS AND METHODS Elasmobranchs were collected from Atlantic coastal waters during the years 1967 to 1972 from Chesapeake Bay, Virginia, and southern New England. Through the cooperation of the Virginia Institute of Marine Science, local fishermen, or research vessel CORSAIR, hosts were collected in trawling nets, traps, or with hook and line. Helminths were fixed in situ or removed from the spiral valve, studied alive, and fixed without pressure in AFA at room temperature. Whole mounts were stained with Ehrlich's acid hematoxylin or Mayer's paracarmine, dehydrated, and mounted according to standard procedures. Some scoleces were cleared in Langeron's lactophenol and mounted in glycerin jelly to facilitate study of the tentacles. Type specimens were obtained from the USNM Helminth Collection for comparison. Drawings were made with the aid of a microprojector and photomicrography. Measurements are in micrometers unless otherwise indicated and are expressed as length by width. Prochristianella hispida (Linton 1890) comb. n.