Fungi associated with passalid beetles and their mites

Among the many parasitic or commensalistic symbionts of Passalidae (Coleopt era) are fungi that live within their hindgut and on the exoskeleton of the beetles and their parasitic mites. Three Eccrinales (Trichomycetes) includ e Leidyomyces attenuatus (= Enterobryus attenuatus), Passalomyces compressu s (= Enterobryus compressus), and an unnamed species originally described b y Heymons and Heymons in 1934. Leidyomyces attenuatus has been found in pop ulations throughout the range of Passalidae in the Americas, whereas P. com pressus and the Heymons' eccrinid are reported only from Neotropical passal id beetles. A new genus and species of branched fungus, Enteroramus dimorph us, lives in the hindgut of the common eastern North American passalid, Odo ntotaenius disjunctus. In axenic culture the fungus converts to a yeastlike growth form. Externally, both the beetles and their mites carry parasitic thalli of many species of Rickia (Ascomycota: Laboulbeniales). The probabil ity that many fungi from Passalidae remain unreported worldwide is discusse d.