| Hybodus Temporal range: 260–100 Ma Late Permian to Late Cretaceous |
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|---|---|
| Hybodus fraasi in the Museum für Naturkunde in Berlin | |
| Scientific classification | |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Chondrichthyes |
| Subclass: | Elasmobranchii |
| Superorder: | Selachimorpha |
| Order: | †Hybodontiformes |
| Superfamily: | Hybodontoidea |
| Family: | Hybodontidae |
| Genus: | Hybodus Agassiz, 1837 |
| Species | |
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See text for species. |
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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. 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 metres (6.6 ft) 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. Firstly, they had two different types of teeth, suggesting a wide diet. The sharper teeth would have been used to catch slippery prey, while the flatter teeth probably helped them crush shelled creatures. Secondly, they had a bony blade on their dorsal fin that probably served a defensive function. The males also possessed claspers, specialized organs that directly insert sperm into the female, and which are still present in modern sharks.[1]
The first fossilized teeth from Hybodus were found in England around 1845. Since then teeth (and dorsal spines) have been recovered from around the world.
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, it was shown feeding on a giant struggling Leedsichthys with Metriorhynchus. Hybodus' name was heard by Nigel Marven's voice when he saw a Hybodus shark attacking a Leedsichthys.
In 2004, the children's book "Jurassic Shark" by Deborah Diffily and colorfully illustrated by Karen Carr highlights a pregnant female Hybodus shark battling a Liopleurodon and hunting ichthyosaurs.
Haines, Tim, and Paul Chambers. The Complete Guide to Prehistoric Life. Pg. 89. Canada: Firefly Books Ltd., 2006.
Diffily, Deborah and Karen Carr. Jurassic Shark. HarperCollins Publishers, Byron Preiss, 2004.