The Big Friendly Giants of the Cambrian Ocean

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Justine Alford

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507 The Big Friendly Giants of the Cambrian Ocean
Rob Nicholls, palaeocreations. Artist's reconstruction of T. borealis.

This is Tamisiocaris borealis, a newly described fossilized creature from Greenland that lived around 520 million years ago. Like certain types of modern whale, it possessed large appendages that were used to filter plankton and other small organisms from the ocean.

These animals belonged to a group called anomalocarids. Anomalocarids were traditionally known as giant apex predators who used similar appendages as those possessed by Tamisiocaris to capture large prey. Intriguingly, Tamisiocaris borealis seems to have actually evolved its filter-feeding equipment from these prey-catching appendages during the Cambrian explosion, and it is therefore somewhat of an ancient equivalent to modern-day suspension feeders. Why some of these animals underwent this dramatic transition in feeding is unclear, but it has happened several other times in history. 


The findings have demonstrated not only the diversity of different anomalocaridid species, but have also shed light on some of the ocean ecosystems that existed during this period. Lead author of the study published today in Nature, Dr Jakob Vinther, said in a press release "The fact that large, free-swimming suspension feeders roamed the oceans tells us a lot about the ecosystem. Feeding on the smallest particles by filtering them out of the water while actively swimming around requires a lot of energy- and therefore lots of food." 

A 3D computer animation of the animal was generated by Dr Martin Stein of the University of Copenhagen, in the hope of gaining insight into how these specialized appendages were utilized to feed. "Tamisiocaris would have been a sweep net feeder, collecting particles in the fine mesh formed when it curled its appendage up against its mouth," said Dr. Stein. "This is a rare instance when you can actually say something concrete about the feeding ecology of these types of ancient creatures with some confidence."

The expeditions carried out in this area have revealed a gold mine of fossils just waiting to be characterized by scientists. Who knows what other exciting discoveries may be in the pipeline.