Eimeria palumbi, a New Coccidian Parasite (Apicomplexa: Eimeriidae) from the Galapagos Dove (Zenaida galapagoensis)

Abstract

Eimeria palumbi is a new coccidian parasite described from one of eight (12.5%) adult Galapagos doves (Zenaida galapagoensis) living on Genovesa Island in the Galapagos Archipelago. Oocysts of the new species are ovoid to ellipsoid, 24.2 x 21.7 (2722 x 24-19) ,im, colorless, with a smooth, double-layered wall; shape index (length/width) is 1.16 (1.05-1.21). A micropyle and polar granules are absent, but an oocyst residuum is present, composed of several irregularly shaped granules loosely held together. Sporocysts are ellipsoid, 15.3 x 8.1 (17-15 x 8-8.5) ,Am with a smooth, single-layered wall and a protruding, nipple-like Stieda body and no apparent substieda body; shape index is 1.89 (2.12-1.76). Sporozoites lie head-to-tail in the sporocysts, each with one large refractile body near one end and the sporocyst residuum composed of scattered nonuniform granules covering the midregion of the sporocyst. No other parasites were found in the fecal contents. The Galapagos dove (Zenaida galapagoensis) is found on all of the major islands and many of the smaller islands in the Galapagos Archipelago. It represents the only endemic columbiform species in the archipelago (Harris, 1974). The present study describes a new coccidian parasite found in Galapagos doves captured on Genovesa Island. Genovesa Island, also called Tower Island, is the northeastern-most island in the archipelago. It is located 35 km north of the equator, approximately 90 km northeast of Santa Cruz Island and 45 km due east of Marchena Island. Genovesa Island is an uninhabited, generally arid island of about 14 km2 and is composed of basaltic lava flows covered with a growth of Opuntia spp. and low trees and shrubs (Jackson, 1985; White et al., 1986). MATERIALS AND METHODS During an ecological expedition in March and April 1987, fecal samples from eight Galapagos doves were collected. Procedures for preserving fecal material and for processing and measuring oocysts were as described earlier (McQuistion & Wilson, 1989). All measurements are in micrometers (,um) with size ranges in parentheses following the means. Oocysts were between 60 and 90 days old when examined and measured. I I am indebted to Dr. P. R. Grant, Princeton University, Princeton, New Jersey for collecting the fecal samples and identifying the birds. I thank the officials of the Charles Darwin Foundation, The Galapagos National Park, the Charles Darwin Research Station, and the Government of Ecuador for permission to conduct the study. I also thank Millikin University for awarding me a grant to fund the project. TRANS. AM. MICROSC. Soc., 110(2): 178-181. 1991. ? Copyright, 1991, by the American Microscopical Society, Inc. This content downloaded from 157.55.39.136 on Tue, 05 Jul 2016 04:17:26 UTC All use subject to http://about.jstor.org/terms VOL. 110, NO. 2, APRIL 1991