An Additional New Species of the Acanthocephalan Genus Neoechinorhynchus

Abstract

During a survey of the parasites of the river carpsucker (Carpiodes carpio) of Lake Texoma, made at the University of Oklahoma Biological Station, the junior author of this paper found numerous specimens of the acanthocephalan genus Neoechinorhynchus. These individuals differ in several points from all the previously described species of that genus. The worms were submitted to the senior author for critical study. Extended observations verified the tentative conclusion that this material represents a previously unrecognized species which is here described as Neoechinorhynchus prolixus n. sp. This is the twentieth species of the family NEOECHINORHYNCHIDAE and the twelfth species of the genus Neoechinorhynchus known from North American fishes. While the members of this genus are not sharply restricted in their host relations on this continent, they are preeminently associated with the members of the CATOSTOMIDAE or suckers. Seven of the twelve species of Neoechinorhynchus now known from North America utilize catostomids as definitive hosts. As has been pointed out in an earlier paper (Van Cleave 1949) it is obvious that diversification of the catostomids on this continent has been accompanied by an extremely active speciation of their acanthocephalan parasites. On no other continent has there been such a conspicuous eruptive evolution of the NEOECHINORHYNCHIDAE. The available records tend to show that some species are practically host specific and of extremely limited geographical distribution. At least in some instances this impression is due to scarcity of data and complete absence of either positive or negative records for large areas of the country. Some of the species will doubtless be found to have broader host tolerance and wider geographical distribution when the parasite fauna of other hosts become better known, since among the ACANTHOCEPHALA similarities in food habits and in habitat of the hosts are recognized as favorable for extension of the host list. However, it is likewise probable that absence of these favorable conditions may form the basis for establishment and maintenance of distinct host specificity for some species. Of 201 individuals of Carpiodes carpio (Raf.) examined from Lake Texoma, 155 were infected by N. prolixus. These yielded a total of 1123 specimens, with the heaviest infection consisting of 80 individuals. No other species of ACANTHOCEPHALA was found in this host of Lake Texoma, nor was N. prolixuts found in any other host. However, an exhaustive survey of the parasites of the fishes has not yet been completed. Extended studies of Ictiobus bubalus (Raf.) (the smallmouth