Extended Studies of Baltomyces Styrax in Idaho and Expanded Distribution of This Isopod Gut Fungus in the USA

Sarah J. Oman, Boise State University
Merlin M. White, Boise State University


Trichomycetes or gut fungi are currently considered to be an ecological group consisting of both fungi and protists that inhabit the guts of arthropods from varied environments. Baltomyces styrax has been included as a member of the Asellariales, a small and understudied order of true gut fungi. Baltomyces styrax has remained monotypic and not been reported formally since it was first described by Cafaro in 1999 from one collection in Louisiana. Herein we report on subsequent collections of this fungus, from both lentic and lotic locations, over the last several years from four other states, most recently in Idaho, where we have records over a 4-year span. We repeatedly collected at one lentic site in Idaho for a period of 5 months, which allowed an extended study of not only the life history of B. styrax but also the discovery of morphological characteristics that were not reported earlier. Therefore, we are emending the species description and providing additional information on the ecology and host range of B. styrax as well as providing a context for comparison to Asellaria, the type genus of the Asellariales. We also extend the known host range and suggest that the fungus is much more widespread than current records indicate.