Fossil Of Wormlike "Walking Cactus" Discovered

Fossils of an ancient, thorny creature dubbed a "walking cactus" have been found in China, a new study says.

The 2.4-inch-long (6-centimeter-long) Diania cactiformis had a worm-like corpse and ten pairs of armored and likely jointed legs. It would have lived about 500 million years ago during a period of fast evolution called the Cambrian explosion.

Study leader Jianni Liu discovered the animal during a 2006 excavation in southwestern China's Yunnan Province.

"I was actually surprised. I said, What's that strange guy with the soft body with very strong legs?" said Liu, an earth scientist at Northwest University in Xi'an, China.

"When I went back and observed it under the microscope, I realized it's not only hilarious, it's very important."

"Walking Cactus" a hint to Arthropod Evolution?

That's because the newfound animal does not look like other lobopodians, a primitive group of creatures that flourished in the Cambrian seas.

Although the walking cactus is part of this group, it has robust appendages like those of new arthropods—joint-limbed animals such as spiders and crustaceans.

The walking cactus's unusual limbs fortify the theory that modern arthropods evolved from lobopodians, the study authors say.

Liu, who found about 30 fossil specimens of the walking cactus, also has some hypotheses for how the being hunted.

For instance, she suspects D. cactiformis may have sucked up tiny creatures in the mud with its nose or used its bristly legs to arrest larger prey.