408-million-year-old fish fossil in Spain

Machaeracanthusgoujeti, a new marine species of the Devonian period.

THE fossilised remains of scales and bones found in Teruel and the south of Zaragoza in Spain have led researchers from the University of Valencia and the Natural History Museum of Berlin to conclude that they belong to a new fish species named Machaeracanthusgoujeti that lived there during the Devonian period (about 408 to 350 million years ago). The fossils are now part of a collection housed in the Palaeontology Museum of Zaragoza.

The study has been published in the journal Geodiversitas. The new species belongs to the class Acanthodii (spiny shark), which are extinct primitive types of fish that shared characteristics with sharks and bony fish.

“The discovery of this new species… expands our knowledge of the biodiversity that existed on the peninsula 408 million years ago, when the modern-day region of Teruel was covered by the sea,” says Héctor Botella, Professor with the palaeontology unit of the University of Valencia and the study’s lead author.

According to a release from the Spain-based Science Information and News Service (SINC), from what we know to date, they only lived during the Palaeozoic era and reached their maximum level of diversity in the Devonian period.

However, the bones typically found in the Acanthodii group grow differently to the bones found now. Therefore, this type could be even more similar to sharks and could date from the very early stages of the radiation of jawed vertebrates, said the release.

The majority of the samples found by the researchers are of juveniles. On the basis of the fossilised remains, the researchers estimate that the largest fish in this species would not reach one metre in length. However, according to Botella, there are animals that can have large bones and be small, and vice versa.

The fossils found in the sediment layers of the Iberian mountain range must surely have belonged to fish that swam close to the coast. “In other words, they must have lived in an epicontinental sea—an extensive but shallow saltwater mass—and it is therefore possible that this area was used as a breeding ground,” he concludes. Larger fossils were found in sediment layers a little further down.