The Collinsium ciliosum, also known as Hairy Collins’ Monster, lived 500 million years ago in what is now China. What’s all the fuss about? This worm had legs and was covered in spikes. It’s one of the first examples of a species developing armor to protect itself from predators.

Just look at that thing.

collinsium ciliosum fossil

Even the fossil looks nasty.

The worm is named after paleontologist Desmond Collins. He discovered a similar fossil in Canada in the 1980s.

Scientists analyzed the fossil in detail and determined it is a distant early ancestor of modern velvet worms.

velvet worm

Image credit: Frupus (via Flickr)

Velvet worms kept the legs but ditched the armored spikes.

“Modern velvet worms are all pretty similar in terms of their general body organisation and not that exciting in terms of their lifestyle,” said Dr Javier Ortega-Hernández of Cambridge’s Department of Earth Sciences. “But during the Cambrian, the distant relatives of velvet worms were stunningly diverse and came in a surprising variety of bizarre shapes and sizes.”

Ortega-Hernández is one of the paper’s lead authors.

You can see how well preserved the Collinsium ciliosum fossil is in the image above. Details of the worm’s full body are easily seen including the digestive tract and even a fine coat of hair-like structures.

What was the Collinsium ciliosum like?

Detailed analysis indicate it had a squishy body with six pairs of feather-like front legs. Nine pairs of rear legs were tipped with claws. From its legs, scientists assume the worm lived a mostly sedentary life. The rear legs would not have been suitable for walking, but would be great for clinging onto surfaces such as sponges. The front legs were used to filter out food.

This sedentary lifestyle meant Collinsium ciliosum could be easy prey. To help combat this threat, the worm sported an armor shield of 72 spikes covering its body.

Ortega-Hernández compared it to another Cambrian fossil, Hallucigenia. “Both creatures are lobopodians, or legged worms, but the Collins’ Monster sort of looks like Hallucigenia on steroids,” said Ortega-Hernández. “It had much heavier armour protecting its body, with up to five pointy spines per pair of legs, as opposed to Hallucigenia’s two.”

Its front legs were also unique with fine bristles used for feeding.

Scientists found the fossil at the Xiaoshiba deposit in southern China. It’s not as popular as the Chengjiang deposit, but it is known for harboring some incredibly well-preserved fossils.

Collinsium ciliosum doesn’t have a direct living ancestor, and maybe that’s a good thing. Could you imagine stepping on one of these critters at the beach?

Image credits: Jie Yang, Javier Ortega-Hernández

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