Studies on some New Ophidian and Avian Coccidia from Uganda, with a Revision of the Classification of the Eimeriidea

Abstract

This paper contains an account of four new Coccidia from Uganda: Caryospora legeri sp.n., from a snake, Psammophis sibilans; Isospora dirumpens sp.n., from a snake, Bitis arietans; Wenyonella africana gen.n., sp.n., from a snake, Boaedon lineatus; and Eimeria urnula sp.n., from a bird, Phalacrocorax carbo lugubris. Eimeria dukei. Lavier 1927, is recorded from a new host, Chaerephon (= Nyctinomus) limbatus (bat).The characters of the new Coccidia are summarised in the diagnoses (pp. 364, 369, 373, 378). There is a list of all the known species of Isospora found in snakes and lizards. It is noted that I. coelopeltis Galli-Valerio 1926, is actually an Eimeria, and its name is amended to E. coelopeltis. The diagnostic characters of the three species of Caryospora are given in tabular form.The discovery of a new type of Coccidia, with oocysts containing sixteen sporozoites, divided between two sporocysts in Dorisiella Kay 1930, and between four in Wenyonella gen.n., necessitated a revision of the systematics of the Eimeriidea.When the genera comprising this suborder (with a few exceptions) are arranged in the ascending order of the number of structural elements (sporocysts and sporozoites) contained in their oocysts, they form parallel series or groups in the horizontal and vertical directions, which consist of homologous members, as represented graphically in Fig. VI (p. 383). The oocyst characters of each genus are determined by those of its four neighbours in the horizontal and vertical groups.This scheme serves as the basis for the new classification proposed, which is represented in Table III (p. 385). The higher systematic units (subfamilies) are distinguished from each other by the number of sporocysts within the oocyst, while the genera of each subfamily differ from each other in the number of sporozoites within each sporocyst, thus forming a homologous series.