Is this Mysterious Fossil A Worm, A Starfish Arm, or a Strange Organism Way Beyond Its Time?

S. Conway Morris and D. Grazhdankin

Eight mysterious fossils found in upstate New York have left paleontologists in confused disagreement. Do they represent 380-million-year-old impressions of worms, starfish arms or one of Earth's earliest forms of multicellular life that survived for hundreds of millions of years longer than we thought? A new study may change what we know about this fascinating relic of our planet's long distant past.

The fossils, some discovered years ago and some newly excavated, belong to a kingdom of simple organisms called Vendobionta. According to the fossil record, these organisms appeared on Earth 600 million years ago and apparently lived until about 542 million years ago, what is known as the Ediacaran Period.

But the new research claims that these strange fossils lived much longer. In the report, published in the journal Lethaia,Gregory Retallack, paleobotanist at the University of Oregon writes that the specimen might have lived beyond the Ediacaran. If Retallack is correct, the history of this organism would have to be completely rewritten.

The strange fossils, called protonymphs, date to the late Devonian period, when upstate New York was a primitive swamp woodland. But they look strikingly similar to vendobionts, which should have been extinct by this time. Could these specimens indicate that some vendobionts survived all the way to the time that animals were first starting to walk on land?

In an interview with New Scientist, Retallack defends his thoughts. He says that, like some vendobionts, protonymphs contain hollow chambers surrounded by iron-rich body walls. If they were worms, as other paleontologists have argued, then the fossilization process might have smashed the body. These fossils show an imprint of an intact body. If these fossils do represent vendobionts, then they appear to be completely out of place in history.

But other experts dispute this logic. "Because something looks vaguely like something else doesn't make it the same," Duncan McIlroy at Memorial University of Newfoundland in St John's told New Scientist .

Perhaps protonymphs aren't their own organism at all. Some scientists theorize that the fossils are part of another organism, such as the arm of a starfish. Paleontologists have discovered protonymphs not far from where they found similar-looking starfish, and in similar geological eras.

Such an enigmatic set of fossils yields no easy consensus. Protonymphs could be some sort of worm, body part of another animal, plant, lichen, or something else entirely. Determining the protonymph's true identity could rewrite a turning point in Earth's history.