Lecophagus antarcticus, described as a new species of predaceous Hyphomycete of rotifers and tardigrades, was collected from cyanobacterial mats and sediments at shallow lake margins on Signy Island, South Orkney Islands, Antarctica. The new species differs from similar Lecophagus species by larger, more robust vegetative hyphae and by producing septate conidiophore branches or conidiophores as terminals of lateral vegetative hyphae. This is the first report of this genus from either freshwater or polar regions.