New Species of Myxosporidia Found in Percid Fishes from Green Bay (Lake Michigan)

Abstract

The following histozoic Myxosporidia of perches collected from Green Bay (Lake Michigan) are described: Myxosoma neurophila sp. n. located in the neural tissue of the midbrain of Perca flavescens and Etheostomum nigrum, Myxosoma scleroperca sp. n. located within the sclerotic cartilage of Perca flavescens and Percina caprodes, and Henneguya doori sp. n. located on the gill filaments of Perca flavescens. Examinations of fishes collected from Green Bay show the presence of Myxosporidia in this western area of the Great Lakes drainage system that have not been observed in its more eastern areas nor in the Mississippi drainage nearby. Among these Myxosporidia two undescribed species of Myxosoma and one undescribed species of Henneguya were found in perches collected from various sites on both the east and west shores of northern and southern Green Bay. These species are herein described. From March to October, primarily in 1961 and 1962, yellow perch of various sizes were obtained from commercial catches, by seining, or by hook and line. Log perch and darters were collected in seines. They were examined systematically, and when found, the myxosporidian spores were studied first in fresh material. Lugol's iodine was used for the identification of iodinophilous vacuoles and also, when necessary, to stain the capsular filaments so that the number of coils could be counted. Polar filaments were extruded by pressure in water mounts. Tissues selected for preservation and sectioning were placed in FAA while smears of cysts were fixed in Schaudinn's fluid; sections and smears were stained either with Harris' or iron hematoxylin with or without counterstains. Measurements Received for publication 4 January 1963. * Supported in part by the Research Committee of the Graduate School from funds supplied by the Wisconsin Alumni Research Foundation. were made from fresh or preserved material as stated. Average sizes were obtained from the measurements of from 50 to 100 spores taken from different cysts and hosts. All measurements are in microns. Drawings are freehand made to scale. Myxosoma neurophila sp. n.