Seven years ago paleontologist Randall Miller and his colleagues at the New Brunswick Museum in Canada hiked around the small town of Atholville hoping to find a few scattered teeth from prehistoric sea creatures. Instead they stumbled upon a perfectly preserved shark head, now identified as the most ancient intact shark fossil.
The 409-million-year-old species, Doliodus problematicus, was a bottom-dwelling predator that resembled a modern angel shark. One of its unexpected features is a pair of inch-long bony spines protruding from the front edge of the fins, which extended sideways from just behind its head. The spines are similar to those of acanthodians, a group of fish commonly considered more closely related to bony fish than to modern sharks. Such calcified features, never before seen on a shark, blur the evolutionary boundaries between the earliest jawed fishes.
This specimen provides the first evidence that early sharks evolved a complex, predatory ...
