Fóssil de escorpião marinho gigante Jaekelopterus rhenaniae: 2.5 metros de comprimento, 390 milhões de anos

quarta-feira, abril 20, 2011

Giant claw points to monster sea scorpion
00:01 21 November 2007 by Roxanne Khamsi

The fossilised remains of a giant claw that once belonged to a sea scorpion roughly 2.5 metres long have been found in Germany.

Researchers say the monstrous creature is the largest arthropod ever known - over 30 centimetres bigger than the previous largest specimen of the same species.

Simon Braddy at the University of Bristol, UK, and colleagues examined the 46-centimetre-long claw, found in a quarry in western Germany, and believe it belonged to a sea scorpion species called Jaekelopterus rhenaniae that roamed the ocean floors some 390 million years ago.

The claw belonged to a specimen of Jaekelopterus rhenaniae roughly 2.5 metres long according to estimates (Image: Braddy et al. Biology Letters)

Some palaeontologists believe that J. rhenaniae used its claws to reach out and grab passing animals, such as fish, to eat. "They were the top predators at the time," says Paul Selden at the University of Kansas in Lawrence, Kansas, US.

Sturdy claws

The claws of these creatures remain long after the rest of their body has disintegrated. "The body segments are quite flimsy," Braddy explains, but "the claws are sturdy, so they preserve better in the fossil record." As a result, his team had to extrapolate the size of the sea scorpion that once owned the massive claw.

Experts typically extrapolate the size of sea scorpions based on measurements of the claw and body size of the few specimens that have survived intact. But Braddy suspects that this simple method might lead to an overestimate of body size.

According to such calculations, the claw his group found would have belonged to a sea scorpion measuring 2.6 metres long. Braddy prefers a more conservative estimate of just under 2.5 metres.

Read more here/Leia mais aqui: New Scientist


Giant claw reveals the largest ever arthropod

-Author Affiliations

1Department of Earth Sciences, University of Bristol Wills Memorial Building, Queen's Road, Bristol BS8 1RJ, UK
2Generaldirektion Kulturelles Erbe, Direktion Archäologie/ErdgeschichteGroße Langgasse 29, 55116 Mainz, Germany
3Department of Geology and Geophysics, Yale University PO Box 208109, New Haven, CT 06520-8109, USA
*Author for correspondence (s.j.braddy@bristol.ac.uk)


The fossil record has yielded various gigantic arthropods, in contrast to their diminutive proportions today. The recent discovery of a 46 cm long claw (chelicera) of the pterygotid eurypterid (‘sea scorpion’) Jaekelopterus rhenaniae, from the Early Devonian Willwerath Lagerstätte of Germany, reveals that this form attained a body length of approximately 2.5 m—almost half a metre longer than previous estimates of the group, and the largest arthropod ever to have evolved. Gigantism in Late Palaeozoic arthropods is generally attributed to elevated atmospheric oxygen levels, but while this may be applicable to Carboniferous terrestrial taxa, gigantism among aquatic taxa is much more widespread and may be attributed to other extrinsic factors, including environmental resources, predation and competition. A phylogenetic analysis of the pterygotid clade reveals that Jaekelopterus is sister-taxon to the genus Acutiramus, and is among the most derived members of the pterygotids, in contrast to earlier suggestions.


Received September 28, 2007.
Accepted October 29, 2007.
© 2007 The Royal Society