New research is describing one of the oldest scorpions in the fossil record called Parioscorpio venator and is revealing much about early animals' migration from aquatic to terrestrial habitats. The scorpion is estimated to have lived sometime between 437.5 and 436.5 million years ago.
Living on both land and sea
The fossils of the scorpion were discovered in Wisconsin back in 1985. They stayed at the University of Wisconsin for 35 years without being studied until paleontologists Loren Babcock from Ohio State University and Andrew Wendruff from Otterbein University acknowledged their importance.
Although an aquatic creature, Parioscorpio venator had a unique anatomy that allowed it to also live on land. It is now considered one of the earliest air breathers known to science.
Scorpions are amongst the first animals to transition to terrestrial living. As such, Parioscorpio venator holds clues to what enabled animals to go from sea to land.
The scientists used microscopes and high-resolution imagery to study these fossils in detail and may have found the key to transitioning from marine to land life. Although the early scorpions didn’t have lungs or gills, they did have an hourglass-shaped structure similar to the respiratory systems seen in modern scorpions.
It was this system that allowed these scorpions to stay on land for extended periods. Wendruff told Gizmodo that this scorpion “was found in what was an ancient near-shore environment with other organisms that lived in the ocean,” but “the preserved respiratory and cardiovascular systems in the fossil were just like modern scorpions which live on land and breathe air.”
She added that Parioscorpio's adaptations represented “a major step in colonizing land."
Another discovery that came out of the research is how little scorpions have changed over time. “Sometimes evolutionary success is dictated by what creature first breaks the adaptive barrier, such as being among the first to become land-capable. The biological model may have been tested and ‘perfected’ early in their evolutionary history, and didn’t need much tweaking afterward,” Babcock told Gizmodo.