A team of Chinese researchers has found a fossil of a 520-million-year-old bizarre
arthropod, resembling a cactus.

Yunnan, China. If we could travel back in time about 520 million years, we would be able to see a weird red cactus walking fast along the bottom of the sea. Though it looked like one, the creature known as Diania cactiformis was not a cactus, but the first missing link known between worms and arthropods. This unusual crea-
ture was about    6 cm long, had six pairs of jointed legs and inhabited southwest China’s Yunnan Province, in the Himalayas, when that area was a large sea. “The importance of Diania for biology is that arthropods are one of the most successful groups of invertebrate animals and it is remarkable to have discovered what could be the most primitive animal with jointed legs of this group”, pointed out Efe Jianni Liu, leader of the joint research team between Germany’s Freie University and China’s Northwestern University of Xian. Liu added that this discovery is “important as it provides evidence of the evolution of arthropods from lobopodians”. Lobopodians were the ancestors of worms, and had soft bodies made up of segments, and legs with claws on their ends. Their fossil records date back to the Cambrian period, around 500 million years ago. Regarding Diania cactiformis fossil, researchers are trying to determine if it could be the most evolved lobopodian or the first arthropod (currently over 80 percent of the living animal species).