In River Monsters, join host, biologist and extreme angler Jeremy Wade, as he catches the extraordinary and supersized fish that lurk in our planet's rivers and lakes. Traveling the globe and risking his life, he searches for mysterious freshwater predators, on a mission to test the myths surrounding these almost supernatural creatures.
Runtime: 60 minutes
River Monsters - Helicoprion - Netflix
Helicoprion is a genus of extinct, shark-like eugeneodontid holocephalid fish. Almost all fossil specimens are of spirally arranged clusters of the individuals' teeth, called “tooth whorls”— the cartilaginous skull, spine, and other structural elements have not been preserved in the fossil record, leaving scientists to make educated guesses as to its anatomy and behavior. Helicoprion lived in the oceans of the early Permian 290 million years ago, with species known from North America, Eastern Europe, Asia, and Australia. The closest living relatives of Helicoprion (and other eugeneodontids) are the chimaeras.
River Monsters - H. bessonowi - Netflix
Helicoprion was first described by Alexander Karpinsky in 1899 from a fossil found in Artinskian age limestones of the Ural Mountains. Karpinsky named the type species Helicoprion bessonowi; Oliver Perry Hay originally described the species. This species can be differentiated from others by a short and narrowly spaced tooth whorl, backward-directed tooth tips, obtusely-angled tooth bases, and a consistently narrow whorl shaft. One of two Helicoprion species described by Wheeler in 1939, H. nevadensis, is based on a single partial fossil found in 1929 by Elbert A Stuart. It was reported as having originated from the Rochester Trachyte deposits, which Wheeler considered to be of Artinksian age. However, the Rochester Trachyte is in fact Triassic, and H. nevadensis likely did not originate in the Rochester Trachyte, thus rendering its true age unknown. Wheeler differentiated H. nevadensis from H. bessonowi by its pattern of whorl expansion and tooth height, but Leif Tapanila and Jesse Pruitt showed in 2013 that these were consistent with H. bessonowi at the developmental stage that the specimen represents. Based on isolated teeth and partial whorls found on the island of Spitsbergen, Norway, H. svalis was described by Stanisław Siedlecki in 1970. The type specimen, a very large whorl, was noted for its narrow teeth that apparently are not in contact with each other. However, this seems to be a consequence of only the central part of the teeth being preserved, according to Tapanila and Pruitt. Since the whorl shaft is partially obscured, H. svalis cannot be definitely assigned to H. bessonowi, but it closely approaches the latter species in many aspects of its proportions. With a maximum volution height of 72 millimetres (2.8 in), H. svalis is similar in size to the largest H. bessonowi, which has a maximum volution height of 76 millimetres (3.0 in).