Washington - Hundreds of fossils of a
primordial sea creature with rake-like claws and a head
resembling a famous fictional spaceship have been unearthed in
Canada, providing a wealth of information about an important
predator from a key time in the evolution of life on Earth.
Scientists on Tuesday said the creature, called Cambroraster
falcatus, was a distant relative of today's arthropods - the
diverse group of animals including insects, spiders and crabs -
and lived during the Cambrian Period 506 million years ago, when
all animal life lived in the oceans.
"Most animals in the Cambrian Period were small, typically a
few centimeters long at most. By comparison, Cambroraster was a
giant, at up to a foot long (30 cm)," said paleontologist Joe
Moysiuk of the Royal Ontario Museum and University of Toronto,
lead author of the research published in the journal Proceedings
of the Royal Society B.
Cambroraster was excavated in Kootenay National Park in the
Canadian Rockies from a rock formation known as the Burgess
Shale that has yielded fossils of a wondrous array of Cambrian
animals. The Cambrian was a time of evolutionary experimentation
when nearly all major animal groups first appeared and numerous
oddballs came and went.
"With its huge head, small body and upward facing eyes,
Cambroraster superficially resembles a horseshoe crab, although
in detail they are quite different animals," Moysiuk said. "Just
like horseshoe crabs, we think Cambroraster spent its time
hanging around near the sea floor, feeding on organisms buried
in the mud."
A complete fossil unearthed in Kootenay National Park in the Canadian Rockies of the marine creature Cambroraster falcatus, which lived 506 million years ago, showing the eyes and the body with paired swimming flaps below the large head carapace. Picture: Jean-Bernard Caron/Royal Ontario Museum/Handout via Reuters
Its large head was covered by a shield-like carapace whose
shape reminded the scientists of the Millennium Falcon spaceship
of "Star Wars" fame. At the front of its body were two large
claws with a succession of parallel outgrowths like a series of
rakes, letting it sift through seafloor mud and strain out any
prey. Tooth-like plates surrounded its circular mouth. It may
have dined upon worms, small fish and larvae.
It belonged to the same group - radiodonts - as the apex
predator of the time, called Anomalocaris, a dangerous hunter
reaching three feet (one meter) long that may even have targeted
Cambroraster.
Radiodonts, among the earliest offshoots of the arthropod
lineage, are usually known from fragmentary remains. But the
scientists found such a large number of beautifully preserved
and complete Cambroraster fossils that they achieved a
breakthrough in the understanding of this significant extinct
group.