Huge lobster-like animal filtered seawater for food 480 million years ago, say fossil hunters
This article originally appeared on Culture24.
Zoologists say oldest example of gigantism, named after Moroccan finder, "fills ecological hole"
A reconstruction of how the newly-discovered anomalocaridid might have looked feeding on a plankton cloud in the sea around 480 million years ago© Reconstruction by Marianne Collins, ArtofFactNamed Aegirocassis benmoulae, after Mohamed Ben Moula, the Moroccan fossil hunter who discovered the remains, the huge sea dweller had paired swimming flaps along its body.
Dr Peter Van Roy, of Yale University, used tiny needle-like tools to chip away at the rock surrounding the discovery, revealing an “exceptionally well-preserved” 3D fossil of the species.
“This would have been one of the largest animals alive at the time,” says Dr Allison Daley, a colleague of Dr Van Roy’s on the study who works at Oxford University’s Department of Zoology.
The complete specimen of the aegirocassis benmoulae© Reconstruction by Marianne Collins, ArtofFact“While filter feeding - filtering water to find food - is probably one of the oldest ways for animals to find food, previous filter feeders were smaller and usually attached to the sea-floor.
“We have found the oldest example of gigantism in a freely swimming filter feeder.
“Without these 3D remains, we may never have got the insight into these animals’ anatomy that we did.”
Part of an extinct marine animal family called the anomalocaridids which first appeared 520 million years ago, the animal’s flaps are likely to have been precursors to the “double-branched” legs which anthropods such as spiders and insects use to notably versatile effect, including sensing the environment, feeding and mating.
Although most anomalocaridids were sharp-like apex predators, possessing spine-covered head limbs and a circular ring of sharp teeth for a mouth, the new species is closer to a whale.
- The full report has been published in the journal Nature.
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Aegirocassis reached a length in excess of two meters, making it one of the biggest arthropods to have ever lived. It foreshadows the later appearance of giant filter-feeding sharks and whales© Reconstruction by Marianne Collins, ArtofFact.
Allison Daley at a fossil dig in the Emu Bay Shale in Australia. This area has yielded many previous Anomalocaridid fossils© Photo: J Paterson, UNE
The zoologist with an Anomalocaridid fossil at the Burgess Shale in Canada© Photo: Parks Canada
A fossil showing the full-length side-view of the spiny 'net' which Aegirocassis benmoulae used to filter its plankton food from sea water© Photo: Peter Van Roy, Yale UniversityScientists create first 3D skull reconstruction of tetrapod from 360 million years ago
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