Twenty-Third Annual Meeting and Symposium of the
Desert Tortoise Council, April 3-5, 1998
Abstracts

In the fall of 1996 eleven fecal samples from wild Sonoran desert tortoises were preserved in the field using 5% formalin and later examined for intestinal parasites. Direct smear and flotation methods recovered an unusual artifact from 8 of the 11 samples. Initially identified as a trematode egg by parasitologists (based on morphology), the organism is now thought to be a fungal oospore. The ovoid oospores bear a conspicuous operculum at the small end, and measure 42.7 X 27.4 (19.3-52.6 X 13.9-44.3) microns. A water bath was set to incubate the “eggs” and recover miricidia, the first trematode life-stage. The “eggs” did not hatch or decompose after weeks in water. During this time over a hundred slides were produced (direct smear), for measurement purposes. The oospore was found attached at the operculum to fungal hyphae in several slides. The hyphal connection was fragile, and tapping the cover slip sometimes dislodged the oospore. The fungus has been found in three separate populations of desert tortoises. The fecal samples testing positive were collected only between late August and September (1996 and 1997), the monsoon season in Arizona. It is possible that oospores are produced during this time on decaying moist vegetation.

Tachygonetris (pinworm) ova were found in all samples. Additional parasites (Entamoeba spp.) were found while viewing slides. Since large samples were originally collected and preserved, the samples can be re evaluated for parasites using ethyl acetate and centrifugation. Results will be presented with results of current incubations of the suspect fungus.