Trichomycetes in aquatic insects from Prince Edward Island, Canada
Trichomycetes, an ecological grouping of fungi and protists associated with the guts of aquatic arthropods, are distributed globally. The diversity of this unique species complex is, however, more completely documented in some parts of the USA and Europe than in Canada. Twenty species of trichomycetes were collected from insect hosts at six sites in Prince Edward Island, situated in the Gulf of St. Lawrence about 14 km off the east coast of New Brunswick. Five new species of Harpellales (Fungi, Kickxellomycotina), Caudomyces longicollis Strongman sp. nov. from Antocha sp. (Tipulidae), Legeriomyces minae Strongman sp. nov. from mayflies, and Smittium ditrichosporum Strongman sp. nov., Smittium insulare Strongman sp. nov., and Smittium tynense Strongman sp. nov. from chironomids are described. Smittium brevisporum L.G. Valle & Santam. and Smittium gracilis L.G. Valle & Santam., previously known only from Spain, are recorded for the first time in North America. A number of species of Harpellales and Amoebidiales (Phylum Mesomycetozoa) previously recorded from the region (P.E.I. and N.S.), and several that are common and widely distributed, were also recovered. Stachylina pedifer Lichtw. & M.C. Williams was collected from chironomids in a stream exposed to seawater during high tide. Trichomycete diversity is high on P.E.I., as it is in many regions where extensive surveys have been conducted, including islands such as Australia and New Zealand. More data from islands may help shed some light on distribution patterns for these obligate endobionts and provide some insights into mechanisms for dispersal.