Dunkleosteus terrelli, an armor-plated fish that lived in the shallow subtropical waters of the Devonian period, about 360 million years ago, is one of the most widely recognized fossil vertebrates due to its large size and status as one of the earliest vertebrate apex predators. New research by Case Western Reserve University scientist suggests the length of this prehistoric predator may have been greatly exaggerated.
Dunkleosteus terrelli is a large arthrodire placoderm fish, but also best known from the latest Devonian Cleveland Shale of Ohio, the United States.
This species is one of the most recognizable prehistoric organisms and is by far one of the most widely known Paleozoic vertebrates, only comparable to the Permian stem-mammal Dimetrodon limbatus in this respect.
Dunkleosteus terrelli’s popularity largely stems from its unique morphology, which includes an extensive dermal skeleton, blade-like jaws, and large size.
These features, as well as its great geologic age, result in this species often being considered ‘one of the first vertebrate superpredators.’
However, in spite of its prominence in paleo pop culture, relatively little is known about Dunkleosteus terrelli as an actual animal.
“Dunkleosteus terrelli is already a strange fish, but it turns out the old size estimates resulted in us overlooking a lot of features that made this fish even stranger, like a very tuna-like torso,” said Case Western Reserve University Ph.D. student Russell Engelman.
“Some colleagues have been calling it ‘Chunky Dunk’ or ‘Chunkleosteus’ after seeing my research.”
Unlike modern fishes, arthrodire fishes like Dunkleosteus terrelli had bony, armored heads but internal skeletons made of cartilage.
This means only the heads of these animals were preserved as fossils, leaving the size and shape a mystery.
Engelman proposes estimating the length based on the 61-cm (24 inch) long head, minus the snout — considered a way to measure that’s…
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