One of many earliest apex predators, and maybe the freakiest to ever hang-out the ocean, might 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 might not have been as much as the duty. As an alternative, A. canadensis might have swiftly hunted gentle prey within the water, researchers report within the July 12 Proceedings of the Royal Society B.
“These have been the orcas … the nice whites of the time,” says paleontologist Jakob Vinther of the College of Bristol in England, who was not concerned within the research. A. canadensis was clearly tailored to be a prime predator, he says, although it appears trilobites may need been too powerful.
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 instructed that it may have preyed upon one other iconic Cambrian critter — the trilobite. Through the years, 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 may break them.
So Bicknell and colleagues in contrast the versatile appendages to these of some trendy arthropods and examined the primitive appendages’ toughness, vary of movement and optimum swimming place by way of pc simulations.
The traditional spiky limbs would have been efficient at grabbing prey, very similar to these of in the present day’s whip spiders, the researchers conclude. However the extremities have been in all probability 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 crew discovered.
Taken collectively, the outcomes recommend that A. canadensis was finest suited to chasing gentle creatures swimming by means of the water and snagging them in its spiky clutches, Bicknell says. “That’s going to completely pincushion one thing gentle and squishy.”
The findings additionally suggest that even the earliest predators might have been specialised hunters, says evolutionary biologist Joanna Wolfe of Harvard College, who was not concerned within the research. “These have been sophisticated ecosystems, regardless that they’re actually historical.”
