512 million years ago, more complex animals were still a novelty on Earth. Still, there was already parasitism: a fossil with hundreds of animals covered with worms-like creatures shows that what would be the first parasites in history. The material was found in southern China’s Yunnan province and suggests that these parasites emerged during an unprecedented evolutionary flowering.
The fossil is from the Cambrian period, when the first arthropods appeared, as insects, and echinodorms, as the starfish. A team at Northwestern University in Xi’an, China, found hundreds of fossilized brachiopods, called Neobolus wulongqingensis. They look like two shells, but many of the fossil records also contained a kind of tubes attached to them. These would be the remains of the first parasites ever found, which were probably similar to some worms.
It is not yet known, however, whether this was a parasitic relationship or whether brachiopods cooperated with such worms. Fossil records show that those without the tubes were larger, that is, they probably developed more than their relatives, something that indicates that the worms were in fact parasites.
Another fact that supports this theory is that the tubes were aligned with the structures responsible for feeding the brachiopods. Thus, they would be kleptoparasites, that is, they would steal their host’s food, making it less developed. The team that made the discovery also does not know if they were mandatory parasites, that is, they only lived on parasitism without being able to maintain themselves without this practice.
For the researchers, it makes sense that the parasites appeared in the Cambrian period because it was precisely there that several species appeared. In addition, it was also at that time that some animal behaviors, such as hunting and digging, appeared, showing a gigantic evolutionary advance.