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. davisii - Netflix
H. ferrieri was originally described as a species of the genus
Lissoprion in 1907, from fossils found in the Phosphoria Formation of
Idaho. An additional specimen, tentatively referred to H. ferrieri, was
described in 1955. That specimen was found in Wolfcampian-age quartzites
exposed on China Mountain, six miles southeast of Contact, Nevada. The
100-mm-wide fossil consists of one and three-quarters whorls and about
61 preserved teeth. Due to weathering, the rest of the fossil was lost
and the preserved section is distorted from slippage of the host rock.
While initially differentiated using the metrics of tooth angle and
height, Tapanila and Pruitt considered these characteristics to be
intraspecifically variable, reassigning H. ferrieri to H. davisii. H.
jingmenense was described in 2007 from a nearly complete tooth whorl
with four and a third volutions (part and counterpart) found in the
Lower Permian Qixia Formation of Hubei Province, China. It was
discovered during road construction. The specimen is very similar to H.
ferrieri and H. bessonowi, though it differs from the former by having
teeth with a wider cutting blade, and a shorter compound root, and
differs from the latter by having fewer than 39 teeth per volution.
Tapanila and Pruitt argued that the specimen was partially obscured by
the surrounding matrix, resulting in an underestimation of tooth height.
Taking into account intraspecific variation, they synonymized it with H.
H. davisii was described initially from a series of 15 teeth found in
Western Australia. They were described by H. Woodward in 1886 as a
species of Edestus, E. davisii. Upon naming H. bessonowi, Karpinsky also
reassigned this species to Helicoprion, an identification subsequently
supported by the discovery of two additional and more complete tooth
whorls in Western Australia. The species is characterized by a tall and
widely spaced tooth whorl, with these becoming more pronounced with age.
The teeth also noticeably curve forwards. During the Kungurian and
Roadian, this species was very common worldwide.
River Monsters - References - Netflix