The endogenous development of four new species of Isospora Schneider, 1881 (Apicomplexa: Eimeriidae) from Australian geckos.

Four new species of Isospora are described from Australian geckoes. Isospora gehyrae n. sp. from Gehyra cf. variegata in South Australia have 18.5-22.5 x 17.5-20.0 microm oöcysts with 10.0-12.5 x 7.5-9.0 microm sporocysts; endogenous stages develop in the host cell cytoplasm. Of the two species found in Heteronotia binoei from northern Queensland, Isospora cytoheteronotis n. sp., with oöcysts of 20.0-26.0 x 17.5-25.0 microm and sporocysts of 10.0-13.5 x 7.5-11.5 microm, undergoes endogenous development in its host cell cytoplasm, whereas I. nucleoheteronotis n. sp., with oöcysts of 17.5-22.5 x 17.5-21.5 microm and sporocysts of 9.0-12.5 x 6.5-10.0 microm, develops in the host cell nucleus. I. oedurae n. sp. from Oedura rhombifer in northern Queensland has oöcysts of 22.5-25.0 x 22.5-24.0 microm and sporocysts of 12.5-14.0 x 7.5-11.5 microm, and undergoes endogenous development in its host cell nuclei.