Had you found yourself in Cleveland 360 million years ago, you’d be swimming in a shallow sea filled with danger. Looming beneath the waves was the fearsome Dunkleosteus terrelli, an apex predator measuring 14 feet long, unlike any fish seen today.
A recent study has shed fresh light on this ancient monster, the first detailed look in nearly a century. Discovered in the 1860s, Dunkleosteus became a key example of a long-lost group known as arthrodires. However, it’s always stood out as a bit of an oddity.
According to Russell Engelman, a biology graduate student leading the research, the last significant study on Dunkleosteus’ jaw anatomy dates back to 1932. “Back then, we didn’t understand much about arthrodire anatomy,” he noted. Most researchers then focused on fitting bone pieces together rather than understanding how they functioned.
Since the 1930s, fossil studies, especially from Australia, have significantly advanced our comprehension of these ancient creatures. Although some recent research explored biomechanical modeling of Dunkleosteus, no one had revisited the actual bone structures in detail until now.
Engelman and his team chose to investigate the world’s largest collection of Dunkleosteus fossils at the Cleveland Museum of Natural History. This impressive collection owes its preservation to the ancient sea, which encased the fossils in black shale that occasionally resurfaces during construction work.
The name Dunkleosteus translates to “bone” — a fitting name since this creature had heavily armored plates on its skull and upper body. Interestingly, like modern sharks, it also had notable amounts of cartilage. Recent findings reveal that cartilage made up nearly half of its skull, much more than earlier estimates suggested. Moreover, researchers discovered a jaw muscle with a unique bony channel, a rare trait among ancient fish.
One particularly bizarre feature of Dunkleosteus is its tooth-like bone blades. While some of its relatives share this trait, it’s uncommon in the broader arthrodire group. This research not only helps us understand Dunkleosteus better but also casts new light on its diverse relatives. Engelman emphasized, “These findings show that arthrodires were not primitive or uniform but instead were a varied group thriving in many ecological niches.”
So, while Dunkleosteus may be a curious creature, its uniqueness adds to the allure of our planet’s prehistoric past. This study is published in The Anatomical Record.
