A NEW COCCIDIAN (APICOMPLEXA, EIMERIIDAE) IN THE NORTHERN POCKET GOPHER (THOMOMYS TALPOIDES) AND A COMPARISON OF OOCYST SURVIVAL IN HOSTS FROM RADON-RICH AND RADON-POOR SOILS

Forty (93%) of 43 northern pocket gophers (Thomomys talpoides) from th e Jemez Mountains, Sandoval County, New Mexico (USA), had coccidian oo cysts in their feces when examined. We describe this parasite, Eimeria jemezi, n. sp. Sporulated oocysts were subspheroidal, 13.3 by 12.2 (1 0 to 17 by 9 to 15) mu m, with sporocysts ellipsoidal, 7.1 by 4.4 (5 t o 9 by 4 to 5) mu m; micropyle and oocyst residuum were absent, but po lar bodies, Stieda bodies and sporocyst residua were present. All goph ers were collected from two sites of similar habitat 7 km apart. One s ite (Rf) had a high soil radon content (greater than or equal to 50 to 70 picocuries (pCi) per liter of air) whereas the other site (R-) had soils that were near average natural levels (1.2 to 1.6 pCi/g uranium nucleotides per gram of soil; <1.9 pCi/g thorium nucleotides). Twenty -one (88%) of 24 gophers from the R+ site had coccidian oocysts in the ir intestines when examined, but none of these oocysts ever sporulated , whereas all 19 (100%) gophers from the R- site had coccidian oocysts in their intestines and 16 (84%) of these samples sporulated normally under laboratory conditions. The elevated radon content of the soil m ay have had an adverse effect on the sporulation of this coccidian whi le it still was intracellular within its host.