In 2015 a team of scientists announced the discovery of a fossil of a previously unknown species of ‘sea scorpion’, which was more than 1.5 meters long. Now, a new fossil found in Scotland of a new specimen of giant sea scorpion ( Slimonia acuminata ) reveals new data.
The slimonia acuminata dates from 460 million years ago and formed the oldest known species of eurypterids, a voracious predators became extinct in the late Paleozoic, both aquatic or amphibious, reaching monstrous sizes among arthropods.
This sea scorpion, which looked more like a sea monster than a scorpion, swam through the seas like a pirate in ancient times. And not only do they have this in common with them, because the study developed by scientists W. Scott Persons (paleontologist) and John Acorn (entomologist), both from the University of Alberta (Canada), has determined that these marine creatures had a thorn dorsal thin at the tip of the tail. This tail was also surprisingly flexible , with a great capacity for movement to attack large predators and prey, according to the conclusions of the work published in the journal The American Naturalist.
Scientists believed that these ancient animals used their tails primarily to swim quickly, flapping it up and down, as lobsters and shrimp do today, and, to a limited degree, also moving it from side to side like a rudder.
However, the dramatic sideward flex of the tail of these well-preserved fossils is something that has never been seen in other sea scorpion specimens.
According to experts, such flexibility suggests a purpose beyond propulsion to sail the seas . The tail could have been turned horizontally to deliver a quick mortal blow with the pointed end or decapitate a victim with the saw tip of the tail while they were restraining it, having its forelimbs nailed into the back of the same (as shown in the image). In both circumstances, this tail saw or sword would have encountered little resistance in the water.
Because Slimonia acuminata appeared very early in the evolution of the sea scorpion, the technique of chopping and decapitating the victims may have been commonplace for the early days of these ancient creatures for much of the early evolution of vertebrates and related to modern arachnids, the authors note.
Reference: WS Persons and J. Acorn. A sea scorpion’s strike: new evidence of extreme lateral flexibility in the opisthosoma of eurypterids. The American Naturalist. 2017. doi: 10.1086 / 691967.
Image credit: NATHAN ROGERS
