Stethacanthus (the Ironing-Board Shark) is a primitive shark and lived in the Late Devonian Period. At around 27 inches long even so, it would have been a tenacious predator, whilst being relatively primitive compared to later sharks, it would have been a highly advanced shark at the time posing a threat to the far more primitive forms still abundant at the time. However advanced this shark was though, the large Hyneria and Arthodire Placoderm apex predators, such as the largest of them all Dunkleosteus, would have regularly attacked and devoured sharks like Stethacanthus. They were minor predators, in a world dominated in the seas by the Placoderms.

Walking with DinosaursEdit

Sethacanthus wasn't seen in any Walking with Dinosaurs series.

Walking with MonstersEdit

A male Hynerpeton was swimming in the river and a Stethacanthus appears and chases the Hynerpeton to kill it. But Stethacanthus however wasnt so lucky after it was clamped shut right in a Hyneria's jaws.

Sea Monsters - A Walking With Dinosaurs TrilogyEdit

Stethacanthus appeared again where Nigel and his crew found a male Stethacanthus appears which have smelled the blood of the dead Placoderm. The Stethacanthus got spooked away by a Dunkleosteous.


In a Seaworld moment, Nigel Marven went to go dive with sharks and remembered some of the prehistoric sharks and the odd shark he identified is called Stethacanthus meaning the Ironing-Board Shark.