Parapteronotus hasemani, the duckbill knifefish, is a species of ghost knifefish found in main river channels and along the margins in the Amazon basin of Brazil and Peru. It is the only member of its genus. This dark-colored knifefish reaches up to about 38 cm (15 in) in total length. Named in honor of (1887-1969), field collector in the Carnegie Museum of Natural History’s Department of Ichthyology from 1908-1911, who collected the type specimen.