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''Helodus'' (from el, ἧλος , 'stud' and el, ὀδούς 'tooth') is an extinct genus of cartilaginous fish from the Upper Devonian through Lower Permian.Arno Hermann Müller: ''Textbook of paleozoology. Volume III, Vertebrates, Part 1.'' Gustav Fischer Verlag, 1985. While the type species, ''H. simplex'' is known from an articulated specimen, the rest of the species in this genus are known entirely from isolated teeth.Itano, W.M., Lambert, L.L. A new cochliodont anterior tooth plate from the Mississippian of Alabama (USA) having implications for the origin of tooth plates from tooth files. ''Zoological Lett'' 4, 12 (2018). https://doi.org/10.1186/s40851-018-0097-8 Over twenty species have been attributed to this genus, many of which may be anterior teeth of other cartilaginous fish. This makes ''Helodus'' a wastebasket taxon. For this reason, only the type species can be confidently attributed to this genus until articulated remains of other species are found. ''H. simplex'' was around 30 centimeters long.
''Helodus'' (from el, ἧλος , 'stud' and el, ὀδούς 'tooth') is an extinct genus of cartilaginous fish from the Upper Devonian through Lower Permian.Arno Hermann Müller: ''Textbook of paleozoology. Volume III, Vertebrates, Part 1.'' Gustav Fischer Verlag, 1985. While the type species, ''H. simplex'' is known from an articulated specimen, the rest of the species in this genus are known entirely from isolated teeth.Itano, W.M., Lambert, L.L. A new cochliodont anterior tooth plate from the Mississippian of Alabama (USA) having implications for the origin of tooth plates from tooth files. ''Zoological Lett'' 4, 12 (2018). References
Carboniferous cartilaginous fish Prehistoric cartilaginous fish genera Taxa named by Louis Agassiz Paleozoic fish of North America {{paleo-cartilaginous-fish-stub