Research carried out by experts from Durham University, U.K., and Yunnan University and Guizhou University in China found that the fossils, that were previously thought to be the oldest Bryozoans, are in fact green algae.

This means that Bryozoans—tentacle-bearing animals that lived in skyscraper-like underwater colonies—are millions of years younger than previously thought, only appearing in the Ordovician period (480 million years ago).

This makes them the only group of fossil animals not to appear in the Cambrian "explosion," a rapid burst of evolution 40 million years earlier.

The delayed appearance of bryozoans shows that the Cambrian was not a unique period of innovation as conventionally thought; instead, new body plans continued to be carved out by evolution over a much longer time period.

The study findings have been published in the journal Nature.

Ancient fossil material discovered in the hills of China revealed previously unseen "soft parts" of Protomelission gateshousei, formerly believed to be the earliest Bryozoan.

This fragile tissue allowed the researchers to interpret Protomelission as a member of the green algal group Dasycladales.