Two New Myxosporida, Henneguya gambusi sp. n. and Myxosoma pharyngeus sp. n., in the Mosquitofish, Gambusia affinis (Baird and Girard)

Abstract

Two new species of Myxosporida, Henneguya gambusi and Myxosoma pharyngeus, are reported from connective tissues of the integument and pharyngeal cavity, respectively, of the mosquitofish, Gambusia affinis. Immature and mature stages of the parasites are described and the nature of their infections are discussed. H. gambusi is monosporous or disporous while MA. pharyngeus is principally disporous but monosporous and polysporous development is also thought to occur. Both species are reported as pathogenic. During a survey of parasites of the mosquitofish, Gambusia affinis (Baird and Girard), from northcentral Oklahoma, two types of myxosporidan infections were found. These parasites are believed to be new species and both are herein described. The specific names H. gambusi and M. pharyngeus, referring to the name of the host and the location of cysts, respectively, are suggested. MATERIALS AND METHODS Three collections of fishes, including 143 mosquitofish, were obtained from Little Stillwater Creek, Payne County, Oklahoma, during September, October, and December 1969. Selected tissues of G. affinis were fixed in Schaudinn's, Kaformacet, or Zenker's fluids, embedded in paraffin, sectioned at 7 ,u, and stained by routine histological methods. The stains used were Delafield's hematoxylin, Heidenhain's iron-hematoxylin, and Mallory's aniline-blue connective tissue stain. Smears were prepared by transferring intact cysts through Schaudinn's fixative, Heidenhain's iron-hematoxylin, or Feulgen's nuclear reagents, alcohol, and clearing agent, followed by rupturing the cysts in a drop of mounting medium. Measurements of spores were made from fresh material in 0.65% NaCl and from fixed and stained spores that had been sectioned in situ or prepared as smears. Thirty-five fresh spores and 35 fixed and stained spores were measured for both H. gambusi and M. pharyngeus. One hundred ninety-four other fish, including 28 Lepomis megalotis, 45 L. cyanellus, 26 Carpiodes carpio, 23 Ictalurus natalis, 14 Cyprinus carpio, 9 Notemigonus crysoleucas, and 49 unidentified cyprinids and catostomids were colReceived for publication 30 April 1971. * Present address: Department of Biology, Lincoln Land Community College, Springfield, Illinois. t To whom reprint requests should be addressed. + Present address: TVA, Muscle Shoals, Alabama. lected and examined but none were found to contain parasites of the type herein described.