Fossil of Weird Cambrian-Era Predecessor of Velvet Worm Found

Today we have velvet worms, or onychophorans, which are soft-bodied creatures living tucked away in moist nooks of tropical forests over the globe, as well as in Australia and New Zealand. They number 180 described species, and most segments of their bodies have short, jointless legs ended with retractable claws.

It turns out the velvet worms' predecessors in the Cambrian era were much, much jazzier. Paleontologists have identified a strange creature with dozens of spikes on its back, and feather-like front legs that it used to catch prey. It has been named Hairy Collins' Monster, or Collinsium ciliosum. The results, from researchers at the University of Cambridge and Yunnan University in China, were published recently in the journal PNAS.

The super-armored worm turned up in a well-preserved fossil in southern China, according to a release, showing that this thorny caterpillar lived about 500 million years ago. That time period was when most major animal groups first appeared in the fossil record. 

"Modern velvet worms are all pretty similar in terms of their general body organization and not that exciting in terms of their lifestyle," said Dr Javier Ortega-Hernández of Cambridge's Department of Earth Sciences, one of the researchers, according to a release. "But during the Cambrian, the distant relatives of velvet worms were stunningly diverse and came in a surprising variety of bizarre shapes and sizes."

One notable thing about their findings is that while there's a pattern of wild-and-crazy ancestors having preceded fairly dull modern relatives (sea lilies, lamp shells), this is the first time this has been found for a soft-bodied group.

The Chinese fossil, for instance, included such details as the digestive tract and hair-like structures on its front end. It also provides learning on some related species: According to Ortega-Hernández, in a release: "There are at least four more species with close family ties to the Collins' Monster, which collectively form a group known as Luolishaniidae. Fossils of these creatures are hard to come by and mostly fragmentary, so the discovery of Collinsium greatly improves our understanding of these bizarre organisms."

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