A 460-million-year old sea scorpion – believed to be the oldest species of eurypterid – has been discovered in the US in the form of 150 fossil pieces spotted in northeastern Iowa from a 27-metre thick sandy shale found in an old meteorite impact crater. The findings have been published in the journal BMC Evolutionary Biology.
An artists’ impression of the newly-discovered species of sea scorpion, the Pentecopterus. Photo credits: Patrick Lynch – Yale University.
The fossil of a hitherto unknown species of “sea scorpion” has been found in Iowa, in the US, by researchers. 1.5 metres in length, it used to be a predator in the oceans of the ancient world. It is thought to be the relative of modern arachnids.
The species found has been named Pentecopterus decorahensis; the researchers drew inspiration from an ancient Greek warship known as “penteconter” that eerily resembles the sea scorpion in shape. It goes without saying that the ancient sea monster was extremely peculiar.
“The new species is incredibly bizarre. The shape of the paddle – the leg which it would use to swim – is unique, as is the shape of the head. It’s also big – over a meter and a half long!” said the lead author of the research, James Lamsdell from Yale University, USA.
Nature has a special way of preserving some of the creatures having walked on the Earth. This sea scorpion appears to be one of them.
“Perhaps most surprising is the fantastic way it is preserved – the exoskeleton is compressed on the rock but can be peeled off and studied under a microscope. This shows an amazing amount of detail, such as the patterns of small hairs on the legs. At times it seems like you are studying the shed skin of a modern animal – an incredibly exciting opportunity for any paleontologist,” said Lamsdell.
The detailed fossils gave room for interpretations as to the function of certain anatomical parts of the sea scorpion. For instance, its rearmost limbs bearing a large paddle together with joints that seem to be locked in place are thought to decrease flex, implying that the Pentecopterus could either swim or dig with the paddles.