A new species of Legeriomyces and other Harpellales reported for the first time in larval insects from Hungary

•Reports new species of Legeriomyces.•First report of the occurrence of Trichomycetes from Hungary.•Describes observations for Stachylina grandispora's spore development.•This report may spur biodiversity research of the group in the region.

Trichomycetes from the guts of aquatic insects have been surveyed for the first time in Hungary. Legeriomyces hungaricus sp. nov. is described along with two new geographic records, L. ramosus and Stachylina grandispora, all of them Harpellales (Kickxellomycotina). The new species is distinguished from others by having smaller zygospores and a characteristic bell-shaped (campanulate) holdfast, unknown so far in other species of Legeriomyces. An unidentified species of Paramoebidium was also observed along with L. ramosus in nymphs of Baetis rhodani (Ephemeroptera). This preliminary report adds to the existing data on gut fungi and we hope will encourage further research on these cryptic endosymbionts in Hungary and its vicinity.