Myledaphus
Myledaphus is a genus of Late Cretaceous cartilaginous fish whose fossils are known from Canada, the Midwest of the United States, Olmos Formation of the Difunta Group of Mexico, and the Beshtyubin and Bissekty Formations of Uzbekistan. It was a freshwater guitarfish that probably reached a length of, and had teeth adapted for a durophagous diet of animals such as clams. Most taxonomic authories place the genus in the Rhinobatidae, with a few placing it with prehistoric sharks, although the latter may be incorrect. Two species are known: Myledaphus bipartitus, the type species, and Myledaphus araucanus, named in 2019.The most common remains of this fish are teeth and vertebra. A study performed on Myledaphus vertebra from Alberta in 2013 revealed that Myledaphus had an estimated maximum age of 16 years. This means that Myledaphus had a shorter lifespan than that of the modern common guitarfish, by a difference of 8 years.Footnotes
