A new species that scientists have named Tamisiocaris borealis lived during the famous Cambrian explosion, a period in which all of the major body plans for animal life on earth were formed. It was a time of unprecedented biodiversity and variety of evolutionary adaptation, producing such strange sea dwellers such as Marella, Opabinia, and the super strange looking T. borealis.
Scientists suspect that T. borealis would have grown up to 70 cm (2.7 ft) (Esben Horn)
T. borealis belongs to a group of predators called Anomalocarididae, critters distinguished by the dual reacher-grabbers which hung off the front of their heads. These appendages were presumably used to snatch slower (or dumber) species of Cambrian life off the seafloor. But in the case of T. borealis, scientists suspect these trademark body parts may have had a slightly different function. Instead of using the appendages like claws, T. borealis may have used them more like rakes, filtering out krill-sized animals much the way certain whale species do with baleen. Scientists base this assumption on the delicate bristles they found attached to the underside of the structures.
Below is a video of how the T. borealis may have creepily reached out and grabbed food in the Cambrian seas.
“Every time you see these filter feeders — these gentle giants — evolving, they evolved from the apex predators” said Jakob Vinther, a paleobiologist at the University of Bristol in England. But why go from hunting to grazing? Were T. borealis just lazier than their predecessors? More likely they were responding to a sudden cornucopia of food, just as future baleen whales were when they evolved. When the water passage between South America and Antarctica formed, it created a burst of krill which whales could have more effectively fed on using baleen. A similar ecological transformation in the Cambrian may have meant that filter feeding made more sense for T. borealis as well.
This isn’t the only awesome prehistoric discovery to come out of the arctic circle this year. Check out Nanuqsaurus hoglundi, T. rex’s pint sized (relatively) Alaskan cousin.