Phallodrilus aquaedulcis Hrabě, 1960, a meiobenthic freshwater oligochaete (Tubificidae) previously known only from Europe, recorded from the Niagara River, North America

During a base-line investigation of benthic invertebrates of the Niagara River, North America, in 1983, a meiobenthic tubificid, Phallodrilus aquaedulcis, was discovered. The species was previously reported only from the River Weser in Germany, and from inland caves in Spain and France. Because the new specimens deviate morphologically from the original description, a redescription using the new material is presented.