An ancient shark with funny teeth

US scientists have introduced us to Galagadon nordquistae, a newly discovered species of freshwater shark from around 67 million years ago.

Its claims to fame include having – in the words of said scientists – tiny teeth that “resemble the alien ships from the popular 1980s video game Galaga”, and being found next to Sue, currently the most complete T. rex specimen ever described.

Unlike its gargantuan cousin the megalodon, Galagadon was a small shark (30 to 45 centimetres long), and related to modern-day carpet sharks such as the wobbegong.

“The more we discover about the Cretaceous period just before the non-bird dinosaurs went extinct, the more fantastic that world becomes,” says Terry Gates from North Carolina State University, US, and lead author of a paper describing the discovery published in the Journal of Paleontology.

Galagadon’s tiny teeth – each less than a millimetre across – were discovered in the sediment left behind when palaeontologists from the Field Museum uncovered the bones of Sue. Gates sifted through the almost two tonnes of dirt with the help of volunteer Karen Nordquist, who was honoured in the naming of the species.

“It amazes me that we can find microscopic shark teeth sitting right beside the bones of the largest predators of all time,” he says. “These teeth are the size of a sand grain. Without a microscope you’d just throw them away.”

Despite its diminutive size, Gates sees the discovery of Galagadon as an important addition to the fossil record.

“Every species in an ecosystem plays a supporting role, keeping the whole network together. There is no way for us to understand what changed in the ecosystem during the mass extinction at the end of the Cretaceous without knowing all the wonderful species that existed before.”