Eusthenodon

Eusthenodon (Greek for "strong-tooth" – eusthenes- meaning "strong", -odon meaning "tooth") is an extinct genus of marine tristichopterid tetrapodomorphs from the Late Devonian period, ranging between 365 and 359 million years ago (Late Famennian). They are well known for being a cosmopolitan genus with remains being recovered from East Greenland, Australia, Central Russia, USA (Pennsylvania), and Belgium. Compared to the other closely related genera of the Tristichopteridae clade, Eusthenodon was one of the largest lobe-finned fishes (approximately 2.5 meters in length) and among the most derived tristichopterids alongside its close relatives Cabonnichthys and Mandageria.

The large size, predatory ecology, and evolutionarily derived characters possessed by Eusthenodon likely contributed to its ability to occupy and flourish in the numerous localities across the world mentioned above. Eusthenodon is attributed to being just one of many cosmopolitan genera within the "Old Red Sandstone" fish faunas of the Upper Devonian. As a result, it has been hypothesized that diversification of Eusthenodon and other morphologically similar tristichopterids were not restricted by biogeographical barriers and were instead limited only by their individual ecologies and mobility.