Life history and ultrastructure of Eimeria bufomarini n.sp. (Apicomplexa: Eimeriidae) of the giant toad, Bufo marinus (Amphibia: Anura) from Amazonian Brazil

摘要

Eimeria bufomarini n.sp. (Apicomplexa : Eimeriidae) is described from the toad Bufo marinus (Amphibia : Anura) in north Brazil, by both light and electron microscopy. The oocysts average 9.2 x 9.0 μm and the sporocysts 6.25 x 3.7 μm. Oocysts mature in the epithelial cells of the intestine and, due to their extreme fragility, usually rupture and release their sporocysts in the host. Among other peculiarities, ultrastructure studies failed to reveal typica Type I and Type II oocyst wall-forming bodies characteristically found in coccidia of terrestrial vertebrates. The presence was shown, instead, of electron-dense bodies similar to those found in the coccidia of fish. This feature, the common possession of a soft, non-resistant wall together with an endogenous sporulation among anuran and piscine coccidia suggests phylogenetic relationships.