Moulting arthropod fossilized in a flash!

by David Catchpoole

Photo by Michael Oard arthropod-sign
An information board for visitors to the Burgess Shale site.
Photo by Michael Oard outcrop
An outcrop of broken shale at the Burgess site.

Have you ever seen an arthropod (e.g. lobster, scorpion, cockroach) shedding its ‘skin’? You’ve got to be in the right place at exactly the right time—it’s all over in minutes. (When an arthropod grows, its exoskeleton coat does not, so the animal has to shed it while making a bigger one.)

So you can imagine paleontologists’ excitement on finding a fossil of the arthropod Marrella splendens, fossilized at the exact moment of moulting!1

‘It’s basically an astounding specimen’, said paleontologist Derek Briggs of Yale University.2

‘The likelihood of capturing such an event is so astronomically small’, said Desmond Collins, a senior scientist at the Royal Ontario Museum in Canada, and one of the researchers who reported the find. ‘The discovery of an arthropod in the act of moulting was exciting because it was so unexpected.’3

Until now, only moulted skins had been found in the fossil record. Dr Collins said that some of those skins even look like they had been shed just moments before being buried and fossilized. But he explained that it’s highly unlikely that a soft-bodied animal such as Marrella splendens would be buried—and then fossilized—during those few minutes of moulting.

Another reason this find is important, said Dr Collins, is that it confirms what paleontologists had suspected; namely, that early arthropods moulted during growth, just as they do today.

This fossil was found in the Middle Cambrian Burgess Shale (conventionally dated to 505 million years ago) in the Canadian Rockies—an area famous for its ‘exquisitely preserved’ fossils of soft-bodied animals.

More than 25,000 specimens of Marrella splendens (not in the act of moulting) have already been collected from here. Obviously, the environmental conditions were just right for quickly burying, killing and fossilizing these creatures—leaving us a beautifully preserved ‘window’ on the past.46

References

  1. Garcia-Bellido, D.C. and Collins, D.H., Moulting arthropod caught in the act, Nature 429(6987):40, 2004. Return to text.
  2. O’Hanlon, L., Early arthropod caught shedding skin, Animal Planet News, , 2 June 2004. Return to text.
  3. BBC News, Ancient arthropod caught moulting, , 25 June 2004. Return to text.
  4. Noah’s Flood covered the whole earth, Creation 21(3):49, 1999. Return to text.
  5. Wieland, C.Fast fossils—billions of well-preserved fossil fish clash with popular belief, Creation 19(4):24–25, 1997. Return to text.
  6. Startling evidence for Noah’s Flood, Creation 15(1):46–50, 1992. Return to text.

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Reader’s comments

Victor M.
Such evidence strongly points to a cataclysmic event, i.e. the Noahic flood.

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