Parasitology, Harold W. Manter Laboratory of


Date of this Version


Document Type



Scientific Survey of Porto Rico and the Virgin Islands, volume XVII, Part 3, pages 257-368.

New York Academy of Sciences, New York, New York, United States, July 15, 1960.

Otto V. St. Whitelock, editor in chief; Franklin N. Furness, managing editor; and Peter A. Sturgeon, associate editor.


Public domain material.



This monograph reports the major part of an investigation begun by Raymond M. Cable in 1951, when he spent one year at the College of Agriculture and Mechanic Arts, University of Puerto Rico, Mayagiiez, Puerto Rico, collecting and studying larval trematodes and the helminth parasites of shore birds and marine fishes. The work there was done under the auspices set forth in the Preface to Part 4, Volume 16, of this series; this part was facilitated especially by Virgilio Biaggi, N. T. Mattox, and Donald Erdman, who rendered invaluable assistance in the collection and identification of fishes. One trip to Mona Island was cut short when a shark attacked and seriously injured Juan Suarez, who took leave of his duties as Librarian of the College so that we could benefit from his skill as a spear-fisherman. Living material was studied to the extent that time permitted, but this report is based largely on fixed and preserved specimens that were brought back to Purdue University, Lafayette, Ind. There, Ather H Siddiqi submitted an analysis of over one half of the collection as a thesis for the Ph.D. degree in January 1959. During 1957 and 1958, he was a David E. Ross Fellow of the Purdue Research Foundation, and completion of the investigation has been supported by Grant Number G-6125 from the National Science Foundation, Washington, D. C. Leave of absence from his position on the staff of Aligarh Muslim University, Aligarh, India, enabled him to participate in this study, and for that opportunity and encouragement in his work he is indebted to M. B. Mirza, Head of the Department of Zoology and to M. A. Basir of that department.


The digenetic trematodes of marine fishes constitute a large group of parasites that have been studied intensively in only a few regions. The present investigation extends knowledge of that group to the Caribbean Sea, in particular, to the waters adjacent to Puerto Rico and Mona Island, where the trematodes previously have received no attention. During 1951 and 1952 more than 125 species were obtained from about 800 fishes representing more than 140 species in that region. Not included in this report are a few trematodes for which material was unsatisfactory because of immaturity or poor condition. Although this study is one of the more comprehensive of its type, it is certain that many species of digenetic trematodes remain to be found in the fishes of the Caribbean region.

A study of this kind has significance beyond mere knowledge of the parasites themselves. As Manter (1940a, 1947, 1955) has stressed, the distribution and host-parasite relationships of the digenetic trematodes have a significant bearing on geology, oceanography and isolation in time and space as a factor in evolution. Manter found, for example, that greater similarity existed be tween the digenetic trematodes of fishes in the Gulf of Mexico and in the tropical eastern Pacific Ocean than between either of those waters and at Beaufort, North Carolina, and farther north in the western Atlantic. That observation supports the view that the Gulf of Mexico was at one time confluent with the Pacific Ocean and separated from the Atlantic by a land barrier now rep resented by the Antilles chain of islands. The present study further supports that view and also provides evidence that deep water between relatively close land masses serves as a barrier to shallow-water fishes and, hence, is an isolating mechanism that has led to a considerable degree of independent speciation among their trematode parasites.

The first digenetic trematodes of marine fishes to be investigated were those of European waters, from which slightly more than 100 species have been reported thus far. Information concerning that group is summarized by Dawes (1956). The principal European investigators were Rudolphi, Stossich, Monticelli, Looss, Odhner, Lebour, and Nicoll. Fish trematodes of the Red Sea, which has its own characteristic fauna, have been investigated almost solely by Nagaty, who has reported about one half the number known for European waters in a series of papers from 1937 to the present.

The studies of Ozaki and Yamaguti chiefly are responsible for the recognition of more than 300 species of digenetic trematodes from marine fishes in Japanese waters. About one fourth that number is known from the Arabian Sea and the Indian Ocean, largely through the efforts of Srivastava, Chauhan, and Gupta.

In a series of papers dating from 1898 to 1940, Linton pioneered the investigation of marine trematodes in the western Atlantic, reporting about 75 species from the Woods Hole, Massachusetts region and many additional ones from Bermuda, Beaufort, North Carolina, and Tortugas, Florida. In that work he was followed by Manter with many publications dating from 1925 until the present and reporting additional species from Maine, the Gulf of Mexico, the Galapagos Islands and, especially, Tortugas, where almost 200 species are known. More recently Manter has extended his studies to the South Pacific so that, with scattered reports by investigators other than those cited above, more than 1,000 species of digenetic trematodes have been described from marine fishes.