This week’s CBC Quirks & Quarks has a story about some of the oldest aquatic scorpions.  They are about 430 to 433 million years old and from the Bruce Peninsula in Ontario.  From the structure of their feet, scientists believe they may have emerged from the water to moult, probably to avoid predators at a very vulnerable time.  During the Silurian, there was very little life on land and what was there was very simple.

The first specimens of the new scorpion species Eramoscorpius brucensis were discovered in landscaping stone in people’s backyards and patios. The rocks were quarried in Canada, but the fossils are very rare, said lead researcher Janet Waddington of the Royal Ontario Museum.  The new species fell into Waddington’s hands almost by happenstance. Museum curators frequently get calls about fossils, most of which are run-of-the-mill, she told Live Science. But a woman who called about an “insect” in her backyard stone wall had something very exciting on her hands.

“When she showed me this fossil, I just about fell on the floor, it was so amazing,” Waddington said.

The fossil was no insect, but rather a scorpion — and a new species at that. Over the years, more specimens trickled in, mostly from patio stones and rock quarries, and one from a mislabeled fossil at a national park on Canada’s Bruce Peninsula. Now, Waddington and her team have 11 examples of the new species, ranging in length from 1.1 inches (29 millimeters) to 6.5 inches (165 millimeters).

There is an addition story at Live Science and the original paper can be found over at Biology Letters of The Royal Society.