Ancient Super-Shrimp Towered Over Other Filter Feeders

/ Source: Live Science
Artists’ reconstruction of Tamisiocaris borealis, unearthed in the Sirius Passet formation in northern Greenland.
Artists’ reconstruction of Tamisiocaris borealis, unearthed in the Sirius Passet formation in northern Greenland.Bob Nichols / University of Bristol

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A new filter-feeding giant that trolled the Cambrian seas has been unearthed in Greenland.

The species, dubbed Tamisiocaris borealis, used large, bristly appendages on its body to rake in tiny shrimplike creatures from the sea, and likely evolved from the top predators of the day to take advantage of a bloom in new foods in its ecosystem, said study co-author Jakob Vinther, a paleobiologist at the University of Bristol in England.

While on an excavation trip in 2009, the team unearthed fragments of strange feeding appendages attached to a head shield from an unknown creature. The appendages, which date to about 520 million years ago, belonged to a group known as anomalocarids, the top predators of their day.

Artists’ reconstruction of Tamisiocaris borealis, unearthed in the Sirius Passet formation in northern Greenland.
Artists’ reconstruction of Tamisiocaris borealis, unearthed in the Sirius Passet formation in northern Greenland.Bob Nichols / University of Bristol

These ancient sea monsters grew to about 70 centimeters (2.7 feet) long and "looked like something completely out of this planet," with massive frontal appendages for grasping prey, huge eyes on stalks, and a mouth shaped like a piece of canned pineapple, Vinther told Live Science.

But the appendages from T. borealis were different from those of other anomalocarids. Instead of large grasping claws, the front pieces sported fine, delicate bristles, much like the baleen found in the mouths of filter-feeding whales. [Video: See How the Giant Used its Filter-Feeding Appendages]

The strange-looking creature likely raked seawater for tiny shrimplike organisms similar to krill, and evolved from predatory anomalocarid ancestors. This shift from predation to filter feeding echoes the evolutionary trajectory of baleen whales and whale sharks, Vinther said.

"Every time you see these filter feeders — these gentle giants — evolving, they evolved from the apex predators," Vinther said.

When predators evolve a filter-feeding strategy, they typically do so because of a new bounty in available food.

T. borealis was described today (March 26) in the journal Nature.

-Tia Ghose, LiveScience

This is a condensed version of a report from LiveScience. Read the full report.

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