Biggest Spider In The World - NOT!

The University's resident arachnid expert Dr Paul Selden has arguably solved one of the greatest mysteries in palaeontology after becoming one of the first scientists to be allowed to examine a fossil of the creature since it was unearthed in Argentina more than twenty years ago.

Megarachne Servinei has appeared in the Guinness Book of Records as the 'World's Largest Spider' and plaster casts of the beast are exhibited in museums across the world, but Dr Selden is in no doubt that it is not a spider.

"As soon as I saw it I knew it wasn't a spider, but an ancient aquatic creature called a sea scorpion," says Dr Selden.

"It has large claws and two big compound eyes whereas spiders normally have eight small eyes. It also appears to have a very robust body or shell with ridges across its back which is not found in any spider known to man."

"This creature probably lived in a swamp and used its claws for sweeping up mud. If you had to compare it to something which is alive today you would probably choose a large crab or a lobster, not a spider."

Megarachne, which has a massive 50cm leg span, and measures more than a metre in length, was discovered in 1980 by Argentine palaeontologist Mario Hünicken who originally classified it as a spider. Mystery has always surrounded the accuracy of Hünicken's findings, but because the fossil was sealed in a bank vault following an ownership dispute, no one has ever been able to verify his work.

Dr Selden was one of the first experts to be allowed to see the fossil, and has since written a Paper with Hünicken, who accepts Dr Selden's new findings. In the Paper they find that Megarachne is not a spider, but a giant eurypterid (sea scorpion) and is closely related to a creature called Woodwardopterus, from the Carboniferous Period, found in Scotland with relatives in South Africa.

"Even though this isn't the biggest ever spider it is clearly an amazing beast. It is no less exciting, just a little less familiar. It means the biggest spider ever is now the living one - The Goliath Birdeater, Theraphosa leblondi," says Dr Selden.