Europe’s Shield, From the Coal

When I think of where to find non-avian dinosaurs, I think of isolated badlands. Documentaries and a few seasons looking for fossils in the American west have only reinforced the connection in my mind. But while such locales often hold what remains of Mesozoic life, they aren’t the only places to find dinosaurs. One of the latest dinosaurs to be described – an herbivore encased in body armor – was found on the floor of a coal mine in Spain.

The dinosaur’s name is a tribute to where it was discovered. Europelta carbonensis roughly translates to “Europe’s shield from the coal.” As Jim Kirkland, Luis Alcalá, and coauthors explain in the PLoS One study describing the dinosaur, the ankylosaur’s bones were found strewn through the remnants of a roughly 113 million year old swamp that Europelta used to call home. This level, rich in plant material, was discovered beneath the productive coal layers of the open Santa María pit.

So far, Kirkland and coauthors report, Europelta is known from two associated skeletons. Together the various elements provide a rough look at the whole animal, although the arrangement of body armor that surrounded the skeleton had to be reconstructed as the component osteoderms were scattered sometime after the Europelta died. Such uncertainties aside, Europelta would have undoubtedly been a low-slung, spiky dinosaur that snarfed low-lying plants in its Cretaceous habitat.

And Europelta is more than just another dinosaur to add to the ever-growing list of prehistoric species being discovered. In the ankylosaur evolutionary tree, Europelta was a nodosaurid. These armored dinosaurs lacked the imposing tail clubs of more famous ankylosaurids such as Ankylosaurus, yet they were also distinct from the strikingly-ornamented polacanthids such as Gastonia.

Within this larger tree of armored dinosaurs, Europelta is just about as ancient as the oldest nodosaurids in North America. This means that prehistoric North America and Europe must have still be connected sometime prior to 110 million years ago. The presence of Europelta at this time also signals a significant shift in dinosaur communities during the early part of the Cretaceous. The more archaic polacanthids were all but extinct, with nodosaurids becoming the prominent form of armored dinosaurs. Exactly why the polacanthids disappeared while the nodosaurids persisted isn’t clear, but the switch appears to be part of a wider dinosaur reshuffling happening early in the Cretaceous.

In almost any form of media, from books to big-budget films, dinosaurs from the Late Triassic, Late Jurassic, and Late Cretaceous are the primary objects of our admiration. Dinosaurs from the early parts of these periods are comparatively poorly-known and overlooked. Yet discoveries such as Europelta are beginning to outline major transitions in the world of dinosaurs that often occurred during the dawning years of Mesozoic periods, from the movement of continents to the evolution of the celebrated creatures themselves. The announcement of a new dinosaur isn’t only the discovery of yet another prehistoric monster. It’s another time capsule that will help us better comprehend our ever-changing planet.

Reference:

Kirkland. J., Alcalá, L., Loewen, M., Espílez, E., Mampel, L., Wiersma, J. 2013. The basal nodosaurid ankylosaur Europelta carbonensis n. gen., n. sp. from the Lower Cretaceous (Lower Albian) Escucha Formation of Northeastern SpainThe basal nodosaurid ankylosaur Europelta carbonensis n. gen., n. sp. from the Lower Cretaceous (Lower Albian) Escucha Formation of Northeastern SpainThe basal nodosaurid ankylosaur Europelta carbonensis n. gen., n. sp. from the Lower Cretaceous (Lower Albian) Escucha Formation of Northeastern Spain. PLoS ONE. 8, 12: e80405. doi:10.1371/journal.pone.0080405