Collinsium ciliosum: Cambrian Spiky Worm Discovered in China

An international team of paleontologists, co-led by Dr Xi-guang Zhanga and Dr Jie Yang of Yunnan University, has described a new species of super-armored worm with legs that lived in what is now China during the early Cambrian, about 500 million years ago.

Reconstruction of Collinsium ciliosum. Image credit: Javier Ortega-Hernandez / Sci-News.com / Dimitris Siskopoulos.

The ancient creature, Collinsium ciliosum (Hairy Collins’ Monster), belongs to a poorly understood group of legged worm-like animals called Lobopodia.

It had a soft and squishy body, 6 pairs of feather-like front legs, and 9 pairs of rear legs ending in claws. Since the rear legs were not well-suited for walking along the ocean floor, it is likely that the worm eked out an existence by clinging onto sponges or other hard substances by its back claws, while sieving out its food with the front legs.

Given its sedentary lifestyle and soft body, Collinsium ciliosum would have been a sitting duck for any predators, so it developed an impressive defense mechanism: as many as 72 sharp and pointy spikes of various sizes covering its body, making it one of the earliest soft-bodied animals to develop armor for protection.

The fossil specimens of Collinsium ciliosum were found in the Xiaoshiba deposit near Kunming, Yunnan Province, southern China.

Collinsium ciliosum. Image credit: Jie Yang.

According to the scientists, Collinsium ciliosum is a distant ancestor of modern velvet worms, a small group of squishy animals resembling legged worms that live in tropical forests.

“Modern velvet worms are all pretty similar in terms of their general body organization and not that exciting in terms of their lifestyle. But during the Cambrian, the distant relatives of velvet worms were stunningly diverse and came in a surprising variety of bizarre shapes and sizes,” said Dr Javier Ortega-Hernández from the University of Cambridge, UK, a co-author of the paper published today in the journal PNAS.

The species resembles Hallucigenia, another otherworldly Cambrian fossil, albeit one which has been the subject of much more study.

“Animals during the Cambrian were incredibly diverse, with lots of interesting behaviors and modes of living,” Dr Ortega-Hernández said.

“Collinsium ciliosum was one of these evolutionary experiments – one which ultimately failed as they have no living direct ancestors – but it’s amazing to see how specialized many animals were hundreds of millions of years ago.”

Source: Sci.news