Paleontologists excavating a site in the Canadian Rockies known as the Burgess Shale have discovered the fossilized remains of a heretofore-unknown species of arthropod with a distinctive horseshoe-shaped upper shell. They whimsically named the species Cambroraster falcatus after the Millennium Falcon starship piloted by Han Solo in the Star Wars franchise. The discovery, reported in a new paper in the journal Proceedings of the Royal Society B, sheds light on the diversity of the earliest relatives of insects, crabs, and spiders.

Discovered in 1909 by paleontologist Charles Walcott and dating back to the mid-Cambrian era some 508 million years ago, the Burgess Shale has since become one of the richest troves of preserved fossils from that period. The late Stephen Jay Gould immortalized its importance in his bestselling 1989 book, Wonderful Life, in which he argued (somewhat controversially) that the sheer diversity of the Burgess Shale fossils was evidence for several unique evolutionary lineages that became extinct, rather that continuing down to today's modern phyla. The Burgess Shale was declared a World Heritage Site in 1980.

In 2013, scientists discovered yet another piece of the Burgess Shale in Kootenay National Park and excavated the fossilized remains of some 50 new species in just 15 days. That's the area where a team of paleontologists affiliated with the Royal Ontario Museum discovered this latest arthropod.

As geologist David Bressan, who was not involved in the discovery, writes at Forbes:

Cambroraster falcatus displays, like Anomalocaris, lateral flaps that stretched along the lower portion of its body and a set of disc-like jaws. The new species was smaller than Anomalocaris, up to a foot long, yet still a giant compared to other Burgess Shale creatures, most less than one inch long. Its body protected by an unusually large carapace covering almost the entire animal. The researchers think that Cambroraster was, like its larger relative, a predator. Unlike Anomalocaris, a fast swimmer thanks to the flexible lateral fins and able to catch prey in open water with its tentacles, Cambroraster used its carapax to plow through the upper layers of the seafloor, catching smaller animals hiding there with a series of appendages and hooked spines surrounding its mouth.

"We really didn't know what to make of it," co-author Joe Moysiuk of the University of Toronto told CBC News. "We nicknamed it 'The spaceship' because we thought it looked a lot like the Millennium Falcon." And the name stuck, to the delight of Star Wars fans everywhere.

"Cambroraster is kind of showing a mish-mash of traits that we see in some modern groups," Moysiuk said of the find's significance. "It's telling us that the Cambrian ecosystems were really complex. This is not a sort of primitive, simple organism. This is a highly specialized predator."

Moment of discovery

Proceedings of the Royal Society B, 2019. DOI: 10.1098/rspb.2019.1079 (About DOIs).

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