A New Species of Eimeria (Apicomplexa: Eimeriidae) from the Green Water Snake, Nerodia cyclopion (Reptilia: Serpentes), in Arkansas, U.S.A.

Abstract

Eimeria cyclopion n. sp. is described from the intestinal contents and feces of 10/15 (67%) green water snakes, Nerodia cyclopion cyclopion, in northeastern Arkansas. Oocysts of the new species are ellipsoidal, 18.7 x 13.1 (14-22 x 12-15) Am, with a smooth, thin, single-layered wall; shape index 1.4 (1.1-1.6). A polar granule and oocyst residuum are present, but a micropyle is absent. Sporocysts are elongate, 13.9 x 4.5 (12-15 x 4-5) Am, each with two filaments that appear to arise from a thin membrane covering the sporocyst; shape index 3.1 (2.8-3.6). A Stieda body and sporocyst residuum are present, but a substieda body is absent. The sporozoites are elongate, 10.6 x 2.9 (10-12 x 2.6-3.2) ,um in situ, each containing spherical anterior and ellipsoidal posterior refractile bodies. A nucleus is located between the refractile bodies. The new form also was found in three sympatric congeners from the study site. In addition, two previously described eimerians were harbored by these hosts. The green water snake, Nerodia cyclopion (Dumeril, Bibron & Dumeril) is a large, heavy-bodied aquatic colubrid that ranges from coastal South Carolina through Florida, west to Louisiana and southeastern Texas, and north through eastern Arkansas to extreme southern Illinois (Behler & King, 1979). The species prefers aqueous areas with sluggish flow and dense aquatic vegetation, including cypress swamps, oxbow lakes, rice fields, river sloughs and bayous, and occasionally estuaries. A variety of prey items are included in the diet of N. cyclopion, although minnows and other small fishes apparently are the most important component (Kofron, 1978). There is a plethora of information available on helminths of N. cyclopion (see Ash & Beaver, 1963; Brooks, 1978, 1979; Little, 1966; Sprent, 1979). However, nothing is known about its coccidian parasites. Recently, we had an opportunity to examine specimens of N. c. cyclopion and other sympatric water snakes from northeastern Arkansas for coccidia. During that period, we found a previously undescribed species of Eimeria and other eimerians in these hosts. A description of the new species is provided 1 We thank B. Beville, B. P. Butterfield, and W. E. Meshaka for assistance in collecting snakes, two anonymous reviewers for critically reviewing the manuscript, and the Arkansas State Game and Fish Commission for Scientific Collecting Permit No. 775. Publication costs, in part, are being met by a grant from the Spencer-Tolles Fund of the American Microscopical Society. 2 Division of Biology, Ackert Hall, Kansas State University, Manhattan, Kansas 66506, U.S.A. 3 Department of Biological Sciences, Arkansas State University, State University, Arkansas 72467, U.S.A. TRANS. AM. MICROSC. SOC., 109(1): 69-73. 1990. ? Copyright, 1990, by the American Microscopical Society, Inc. This content downloaded from 157.55.39.106 on Mon, 10 Jul 2017 17:40:25 UTC All use subject to http://about.jstor.org/terms TRANS. AM. MICROSC. SOC.