Nematophagous fungi from the maritime Antarctic

Eighteen taxa of terrestrial predacious fungi (nematode-trapping species and endozoic parasites of nematodes) are reported from the maritime Antarctic (15 taxa from Signy Island, South Orkney Islands, and ten taxa from Galindez Island, Argentine Islands). Fifteen have been positively identified to species level, twelve of which have not previously been recorded in the Antarctic. They were isolated from several locally dominant moss species and soil associated with the two native phanerogams. Monacrosporium ellipsosporum and M. cionopagum were the most widely distributed trapping hyphomycetes while Harposporium anguillulae was the most frequently occurring endozoic fungus. All taxa were isolated from cultures maintained at 18.5°C but only five of these were recorded in cultures kept at 7°C. Eight different trapping mechanisms were recorded with adhesive knobs being the commonest structure. The relationship between fungal taxon and moss species or soil type is discussed. Although several species were recorded only in single samples M. ellipsosporum appeared to be associated with calcicolous mosses. M. cionopagum and H. anguillulae have comparatively wide ecological amplitudes. No nematophagous fungi were isolated from permanently saturated moss carpets or from the strongly acidic turf-forming Polytrichaceae. The possible importance of these fungi in the energy dynamics and their influence on nematode populations of Antarctic terrestrial ecosystems is considered.

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