This historic, Lovecraftian apex predator chased and pierced comfortable prey

One of many earliest apex predators, and maybe the freakiest to ever hang-out the ocean, could have additionally been a fragile eater.

For many years, paleontologists have assumed that the long-extinct Anomalocaris canadensis — roughly translated as “the irregular shrimp from Canada” — used two spiny appendages on its face to seize arduous trilobites off the seafloor and crush and eat them. However a brand new evaluation suggests the weird hunter could not have been as much as the duty. As a substitute, A. canadensis could have swiftly hunted soft prey within the water, researchers report within the July 12 Proceedings of the Royal Society B.

“These have been the orcas … the good whites of the time,” says paleontologist Jakob Vinther of the College of Bristol in England, who was not concerned within the examine. A. canadensis was clearly tailored to be a high predator, he says, although it appears trilobites might need been too robust.

A. canadensis reigned roughly 500 million years in the past. With a physique so long as a housecat, it was among the many largest creatures of the Cambrian interval (SN: 2/19/15; SN: 4/24/19). Some researchers had recommended that it might have preyed upon one other iconic Cambrian critter — the trilobite. Over time, scads of fossilized injured trilobites have been unearthed, suggesting one thing had attacked them.

However paleobiologist Russell Bicknell of the American Museum of Pure Historical past in New York Metropolis had reservations. Trilobite exoskeletons have been arduous and thick, and nobody had but introduced proof that A. canadensis might break them.

So Bicknell and colleagues in contrast the versatile appendages to these of some fashionable arthropods and examined the primitive appendages’ toughness, vary of movement and optimum swimming place by way of laptop simulations.

The traditional spiky limbs would have been efficient at grabbing prey, very similar to these of as we speak’s whip spiders, the researchers conclude. However the extremities have been most likely too delicate to assault well-armored prey. Moreover, A. canadensis would have moved most effectively when its appendages have been outstretched in entrance, like Superman’s arms in flight, the workforce discovered.

Taken collectively, the outcomes counsel that A. canadensis was finest suited to chasing comfortable creatures swimming by way of the water and snagging them in its spiky clutches, Bicknell says. “That’s going to completely pincushion one thing comfortable and squishy.”

The findings additionally suggest that even the earliest predators could have been specialised hunters, says evolutionary biologist Joanna Wolfe of Harvard College, who was not concerned within the examine. “These have been sophisticated ecosystems, regardless that they’re actually historic.”