Kingdom Animalia
Phylum Chordata
Class Sarcopterygii
Subclass Tetrapodomorpha
Order Rhizodontida
Family Rhizodontidae
Genus Rhizodus
1st Species Rhizodus ornatus
2nd Species Rhizodus hibberti
3rd Species Rhizodus gracilis
Other attributes
Time Range 330-300 mya
Location United Kingdom, Ireland
Name Meaning Root tooth
Physical Dimensions 6-7 meters long
Dietary Classification Carnivore

Rhizodus is a rhizodontid rhizodontid lobe-finned bony fish from the Mississippian-Pennsylvanian of the United Kingdom and Ireland. It was named in 1836 by Ramsay H. Traquair. It was the biggest lobe-finned fish to exist, as well as one of the last non-tetrapod tetrapodomorphs to exist.


Rhizodus had the generic lobe-finned fish body plan; a coelacanth-like body plan with a bulky body, fleshy, lobe-like fins, and a big head with semi-small jaws. However, it had a few major differences; for example, its head was shorter than those of other tetrapodomorph fish, and it had sharp, fang-like teeth in the front of its mouth. Its body would have been covered in scaly skin.


Rhizodus was a predator, preying on amphibians, sharks, and smaller lobe-finned fish. Unlike the small teeth of other lobe-finned fish, its teeth were big and fang-like, and were used to tear the flesh of its prey.


Rhizodus lived in freshwater lakes, rivers, and swamps, swimming through the waters in search of prey. Unlike other lobe-finned fish, which had small teeth and swallowed their prey whole, it had huge, fang-like teeth in the front of its mouth, followed by teeth that gradually got smaller in size. Those teeth were used to tear flesh, as well as to rip prey into pieces small enough to eat. Aside from swimming up to prey and tearing it apart, Rhizodus would have used its strong and sturdy fins to crawl out of the water to catch escaping amphibians, as well as to slide into the lakes and catch its prey by surprise.

In popular cultureEdit

Rhizodus was featured in a special episode of the documentary River Monsters, appearing alongside Xenacanthus, Xiphactinus, Leedsichthys, Megapiranha, Helicoprion, and Dunkleosteus as candidates for the most terrifying prehistoric river dweller. Out of all the possible candidates, Jeremy Wade, the scientist behind the show, selects it as the winner due to its freshwater habitat, immense size, power, ferocity, and deadly bite.

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