MYRMECOMYCES-ANNELLISAE GEN-NOV, SP-NOV (DEUTEROMYCOTINA, HYPHOMYCETES), AN ENDOPARASITIC FUNGUS OF FIRE ANTS, SOLENOPSIS SPP (HYMENOPTERA, FORMICIDAE)

Two strains of a parasitic fungus, differing only in assimilation of cellobiose and colonial morphology on some media, occur in the haemolymph of fire ants in the United States and Argentina. In the host, obclavate yeast cells bud from a narrow base at the larger pole. A true, septate mycelium without clamp connections readily develops in vitro, and has been observed on rare occasions in the host. The hyphal septum has a simple, central pore. Morphology in insect tissue culture medium closely resembles that in the host; however, in simpler media the cells and hyphae are pleomorphic and often only mycelial. Chlamydospores are produced; otherwise, sporulation has not been observed. The morphological, cultural, and physiological characteristics are described, and the fungus is named as a new species, Myrmecomyces annellisae, representing a new genus. Gross pathology, histopathology, or changes in host behaviour have not been observed; however, parasitized hosts appear to succumb more readily to stress.