Helodus (from Greek, Modern (1453-);: ἧλος, 'stud' and Greek, Modern (1453-);: ὀδούς 'tooth')[1] is an extinct genus of cartilaginous fish from the Upper Devonian through Lower Permian.[2] 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.[3] 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.[4] 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.