Hybodus

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Hybodus
Fossil range: Late Permian to Early Cretaceous

Hybodus fraasi in the Museum für Naturkunde in Berlin

Kingdom:	Animalia
Phylum:	Chordata
Class:	Chondrichthyes
Subclass:	Elasmobranchii
Superfamily:	Hybodontoidea
Family:	Hybodontidae
Genus:	Hybodus Agassiz, 1837

Species

See text for species.

Sharks Portal

Hybodus ("humped tooth") is an extinct genus of once-common, widespread and long lived sharks, first appearing towards the end of the Permian period, and disappearing at the beginning of the Cretaceous (230-90 million years ago). During the Triassic, Jurassic, and Cretaceous periods the hybodonts were especially successful and could be found in shallow seas across the world. For reasons that are not fully understood, the hybodonts became extinct near the end of the Cretaceous period.

Hybodus species grew to about 2 m in length, and are believed to have been opportunist predators. It was not very big, but had the classic streamlined shark shape, complete with two dorsal fins that would have helped it steer with precision. The mouth was not large, and rather than ruthlessly hunt large prey, Hybodus, was capable of eating a wide range of foods. They had several distinct features that made them stand apart from other primitive sharks: they had two different types of teeth (both sharp and flat), suggesting a wide diet (sharp for catching slippery prey, flat for crushing shelled creatures) , a bony blade on their dorsal fin for apparent protection, and the development of "claspers". These specialized organs aid males in reproduction by directly inserting sperm into the female. This last development has been passed on to modern sharks.

The first fossilized teeth from Hybodus were found in England around 1845. Since then teeth (and occasionally dorsal spines) have been recovered from around the world.

[edit] Species

Hybodus houtienensis
?Hybodus butleri
?Hybodus obtusus
?Hybodus parvidens
?Hybodus rajkovichi
?Hybodus montanendis

[edit] In popular culture

Hybodus was featured in the third episode of the popular 1999 documentary series Walking with Dinosaurs, being attracted to the blood of an Ophthalmosaurus in labor. It was unidentified in this episode. Hybodus made its return in the 2003 spin-off Sea Monsters, briefly shown feeding on a giant struggling Leedsichthys with Metriorhynchus.