Physical appearance and biologyEdit
Behaviour and traitsEdit
Named after Dr David Dunkle, an American palaeontologist who studied its fossils, Dunkleosteus could grow to almost 10 metres long, making it the largest predator in the Devonian sea. It was an alien-looking animal, with a head that was encased in solid and inflexible armour-plating, and a muscular body that was streamlined - much like that of a shark.
The secret of Dunkleosteus' success was its mouth. The evolution of a movable lower jaw, around 420 million years ago, marked the start of the fishes' rapid rise to dominance in the seas. Dunkleosteus was a magnificent example of this. Instead of teeth it had two razor-sharp shearing plates made from bone, which would flash past each other in a scissor-like motion. The jaws were powerful, and anything caught between them would have been sliced clean in two. This allowed it to hunt other large animals, killing them and then eating them with an efficiency that jawless animals could not hope to match. The evolution of the jawed fish coincides with the decline of many other marine animals, including the trilobites, sea scorpions such as Pterygotus and jawless fish like Cephalaspis. It is likely that the jawed fish outcompeted all these animals.
Dunkleosteus would have pursued its prey with a sudden burst of speed, before crippling or killing them with its shearing plates. Some fish defended themselves with large spines on their dorsal fins, which would stick in the roof of Dunkleosteus' mouth, preventing the fish from being swallowed. At least one Dunkleosteus died after getting such a fish stuck in its throat.
The lack of teeth meant that it couldn't chew and so had to swallow large pieces of food in their entirety. Sometimes the stomach couldn't cope with such large chunks of meat, and Dunkleosteus would be forced to vomit on to the seabed. Balls of this fossilized vomit are common in Late Devonian rocks.
During a reconnaissance dive, the cameraman Mike recorded footage of an adult Dunkleosteus. Fortunately for him as well as Nigel Marven and the rest of the crew, he managed to capture close-up and high quality recordings of the fish's body and jaws. When Mike returned to The Ancient Mariner, he and the rest of the crew watched the footage and were amazed at the Dunkleosteus.Later, after catching some bait and preparing the shark cage, Nigel climbed into the cage with the bait in hand. As he was lowered into the water, he was confronted by a hungry Stethacanthus. However, the shark was scared off by an adult Dunkleosteus, eager to eat. After battering Nigel and the shark cage, Nigel decided to hand-feed the fish and offered it the placoderm wrapped in chainmail. The Dunkleosteus grinded through the armour plates and chainmail, only leaving the tail. After dropping the spoils, a baby Dunkleosteus approached the remains and fed until the adult returned and cannibalized on the juvenile. As it swam away, the adult vomited up the chainmail and other indigestible parts.
Behind the scenesEdit
List of appearancesEdit
- Sea Monsters
- Sea Monsters book
- The Complete Guide to Prehistoric Life
- There is no evidence of Dunkleosteus being a cannibal.