Sea worm fossil gives clues to 'common ancestor'

7 July 2016 

Fossils of a sea worm that lived on the ocean floor about 500 million years ago are giving new insights into how early creatures evolved.

Tube-like structures once thought to be a type of seaweed were made by a worm that lived a solitary life on the sea bed, say scientists.

The research, published in the journal BMC Biology, suggests the animal, Oesia, was a filter feeder.

Fossil discoveries of this kind are rare.

The research was carried out by academics from the universities of Cambridge, Toronto and Montréal, and at the Royal Ontario Museum in Toronto.

Prof Simon Conway Morris, from St John's College, University of Cambridge and a co-researcher on the study, said: "Oesia fossils are pretty enigmatic - they are very rare and until now we could not prove which group they belonged to.

"Now we know that they were primitive hemichordates - perhaps the most primitive of all."

Common ancestor

Hemichordates are a group of creatures that belong to a larger group called deuterostomes, of which vertebrates (including humans) form a separate branch.

Karma Nanglu, from the University of Toronto, and the study's lead researcher, said: "Hemichordates are central to our understanding of how deuterostomes evolved.

Continued ...

Nature's Glowing Slime: Scientists Peek Into Hidden Sea Worm's Light

Nov. 13, 2013 — Scientists at Scripps Institution of Oceanography at UC San Diego and their colleagues are unraveling the mechanisms behind a little-known marine worm that produces a dazzling bioluminescent display in the form of puffs of blue light released into seawater.

Found around the world in muddy environments, from shallow bays to deeper canyons, the light produced by the Chaetopterus marine worm—commonly known as the “parchment tube worm” due to the opaque, cocoon-like cylinders where it makes its home—is secreted as a slimy bioluminescent mucus.

The mucus, which the worms are able to secrete out of any part of their body, hasn’t been studied by scientists in more than 50 years. But two recent studies have helped reignite the quest to decode the inner workings of the worm’s bioluminescence.

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