New species of Smittium and Stachylina and other trichomycetes in larval Diptera from streams in Nova Scotia, Canada 1This paper is dedicated to Jo-Ann Frost, one of the first students of these fungi in Nova Scotia, and to the numerous other undergraduates who have engaged with us in our studies of gut fungi, not only in the province, but wherever our studies have taken us.

The guts of non-predaceous invertebrates in aquatic and moist terrestrial habitats are often colonized by an ecological group of microorganisms called trichomycetes. Taxonomically, these endobionts are currently a diverse, polyphyletic assemblage including both zygomycetous fungi as well as protistan species. Trichomycetes are worldwide in distribution and are from varied habitats, but the species inventory of gut fungi from hosts in Canada is far from complete. We summarize the findings from our earliest surveys (from 1997 to 2005) and collections of candidate dipteran hosts in Nova Scotia. Nine new species of gut fungi are added to the inventory list, including the following seven Smittium spp.: Smittium aggregatum, Smittium gronthidium, Smittium papillum, Smittium pavocaudatum, Smittium radiculans, Smittium sparsum, and Smittium verticillatum, and the following two Stachylina spp.: Stachylina brevicellaris and Stachylina subgrandis. Four of the other 13 Harpellales, Pennella digitata, Smittium megazygosporum, Stachylina penetralis, and Zancudomyces culisetae are reported for the first time in Atlantic Canada. Also recorded is Paramoebidium curvum, with many more specimens of this genus from various locations and hosts included as Paramoebidium spp. only. We suggest that future collections of Diptera, to further document and discover trichomycetes, are warranted across the varied host habitats that abound not only in eastern Canada but the rest of the country as well.