Ancient Sea Scorpion Bigger than Humans Unearthed

Researchers have found the fossilized claw of a 2.5-meter (8-foot) sea scorpion, a creature straight seemingly straight from a B-grade horror movie, living long before the age of dinosaurs.

The 390-million-year-old specimen unearthed in a German quarry is leading scientists to believe that prehistoric spiders, insects and crabs were likely all much larger than previously believed, say researchers at Britain's Bristol University. The find was described by university researcher Simon Braddy and colleagues in the journal Biology Letters.

"This is an amazing discovery," said Braddy. "We have known for some time that the fossil record yields monster millipedes, super-sized scorpions, colossal cockroaches, and jumbo dragonflies but we never realized, until now, just how big some of these ancient creepy-crawlies were."

The claw of the sea scorpion Jaekelopterus rhenaniae measured 46 centimeters (18 inches) long, indicating the creature was significantly larger than any previous estimates of the ancient critter. creatures with external skeletons and segmented bodies, are mostly quite small today. Scientists are puzzled about why creatures grew so incredibly large in prehistoric times.

Some scientists theorize that they may have been able to support their titanic size due to higher levels of oxygen in the atmosphere of the past. In this theory, the secret to gigantism is in the insect respiratory system. In contrast to us vertebrates, where blood transports oxygen from the lung to the cell, insects deliver oxygen directly through a network of blind-ending tracheal tubes. As insects get bigger, this type of oxygen transport becomes far less effective. But increase the atmospheric oxygen levels, as happened in the late Paleozoic, and longer tracheal tubes could theoretically allow gigantic variations to evolve. Another theory is that the sea scorpians evolved in an "arms race" alongside their prey, the early armored fish.

Posted by Rebecca Sato

Bizarre Tropical Fish -Mimics Evolution of Land Animals
500 Billion Tons of Prehistoric Organic Matter May Massively Accelerate ‘Global Warming’
Ancient “Eyes” of Early Earth Are Key to Biggest Sex Event on the Planet

Links:
http://www.reuters.com/article/scienceNews/idUSL2161277720071121
http://www.aps.anl.gov/Science/Highlights/2007/20070808.htm