Urolophus

Urolophus is a genus of round rays mostly native to the western Pacific Ocean and the Indian Ocean, though one species occurs in the Pacific waters of the Mexican coast. Müller and Henle erected Urolophus in an 1837 issue of Bericht Akademie der Wissenschaften zu Berlin. The name is derived from the Greek oura, meaning 'tail', and lophos, meaning 'crest'. In Urolophus, the outer rims of the nostrils are not enlarged into lobes, but may form a small knob at the back. A fossil species, Urolophus crassicaudatus, has been found in Mount Bolca, northern Italy, in deposits dating back to the late Ypresian stage of the Eocene epoch (49 Ma).