Racoscorpions, or eurypterids, were one of the largest marine predators of the Paleozoic, reaching lengths of up to eight feet (2.5 meters). Their distribution covered vast areas of water, but little is known about the crustaceans from modern Australian rocks. The authors of the new paper filled the gap by describing fossils of the genera Pterygotus and Jaekelopterus from different parts of the continent. Based on this, paleontologists assumed that the crustaceans swam across the ocean during migrations, or perhaps even regular migrations.

The largest predators of the modern biosphere are vertebrates. However, this was far from always the case: at first, their size was surpassed by completely different animals, for example, scorpions. Now they are more often called eurypterids (Eurypteridae) and chelicerae (along with spiders, mites, swordtails, etc.).

The dimensions of the scorpions are impressive: the largest representatives of the species Jaekelopterus rhenaniae reached 2.5 metres in length. With their claw-like limbs and long, sometimes spiny tails, they could easily bring down large prey. Even the tough outer coverings of trilobites or placoderms did not save us; traces of their crustacean diet suggest that predators would have crushed them.

During their heyday in the Mesozoic era, from the Ordovician to the Permian extinction, eurypterids were widely distributed in the seas, living in rivers, and even on land. The vast majority of fossil finds, however, are in North America and Europe.

The southern continents, which are “pieces” of the Gondwana supercontinent, can boast fewer such finds. Australia, on the other hand, has very few scorpions. But now, thanks to the authors of a new article for the journal, their numbers have increased. Gondwana Research.

Fossils have been found in different parts of the continent, in New South Wales and Western Australia. They date to the late Silurian and early Devonian periods respectively. They are the remains of the exoskeletons of scorpions representing parturition. Pterygotus And Jaekelopterus. Clearly, J. rhenaniae — the largest known eurypterid.

The same crustaceans later lived far away from Australia in Laurentia, Avalonia and Baltica (parts of the modern northern continents). It is noteworthy that both animals have a similar paleogeographic distribution and a very wide distribution. But Jaekelopterus less frequently encountered in general Pterygotus.

After studying Australian crustaceans and their similarities to their northern cousins, paleontologists concluded that they may well have crossed the ancient ocean. Given the predators’ size (primarily Jaekelopterus ) and their possible strength. In the future, scientists hope to find out whether this is a one-time resettlement to new lands or a regular migration of scorpions across the ocean.