21 November 2007Steven Morris
It is enough to give people with arachnophobia a large dose of the heebie-jeebies. Scientists have discovered the fossilised claw of a sea scorpion that suggests the giant scorpions, spiders and crabs that once crawled around the world were even bigger than previously thought.
Found in a German quarry, the claw is 46cm (18ins) long, suggesting the sea scorpion was 2.5m (8ft) long - almost two feet longer that it was previously thought the aquatic creatures grew to. Because land-based scorpions and spiders are believed to have descended from the sea scorpion, scientist believe the discovery means that they also may have been even bigger than had been believed.
Dr Simon Braddy from the department of earth sciences at the University of Bristol, co-author of an article about the find, said: "This is an amazing discovery. We have known for some time that the fossil record yields monster millipedes, super-sized scorpions, colossal cockroaches, and jumbo dragonflies, but we never realised, until now, just how big some of these ancient creepy-crawlies were. I think the claws on this creature would have been powerful enough to rip someone to shreds." Fortunately for mankind, humans were not on the scene until millions of years later.
The claw was found by scientist Markus Poschmann in rocks 390m years old at a quarry near Prüm in Germany. The research is published online in the Royal Society's journal Biology Letters.
Poschmann said: "I was loosening pieces of rock with a hammer and chisel when I suddenly realised there was a dark patch of organic matter on a freshly removed slab. After some cleaning I could identify this as a small part of a large claw. Although I did not know if it was more complete or not, I decided to try and get it out. The pieces had to be cleaned separately, dried, and then glued back together."
One theory is that there was little competition from vertebrates, so ancient arthropods like the sea scorpion were able to flourish. Another is that there was more oxygen in the atmosphere. "There is no simple single explanation," said Braddy. "I believe it could be because they preyed on large, armoured fish. It was in their interest to be bigger than the fish."
The creature had a strongly armoured, jointed body, a pair of large "paddles", eight walking legs, and two front limbs with serrated claws. Braddy said it was possible the fossilised remains of even bigger sea scorpions could be out there. "If we look in the right places we might find even bigger examples," he said.
http://www.guardian.co.uk/science/2007/nov/21/dinosaurs.fossils
