Ceratodus tunuensis was named by Agnolin et al. (2018) [Robust dipnoan diagnosable on the basis of the following combination of characters (autapomorphies marked by an asterisk*): (1) five ridges on upper tooth plates and four ridges on lower tooth plates; (2) relatively short crests that are separated by wide and shallow inter-ridge furrows; (3) upper tooth plates with well-developed mesiointernal angle; (4) lower tooth plates with lingual margin uniformly convex*; (5) upper tooth plates with straight to slightly concave lingual margin; (6) first ridge of upper tooth plates subequal in size to other ridges; and (7) occlusal surface of the tooth plates with wide and deep occlusal pits that are randomly distributed along most of the tooth plate.]. Its type specimen is NHMD 11590, a tooth (a right upper tooth plate lacking the labial half of the first ridge), and it is a 3D body fossil. Its type locality is Ceratodus tunuensis-type locality, which is in a Norian terrestrial mudstone in the Fleming Fjord Formation of Greenland.