China News Service, Beijing, March 9th (Reporter Sun Zifa) The internationally renowned academic journal "Nature" recently published a paleontology paper jointly researched by Chinese and foreign scholars, pointing out that the researchers identified a species of the Cambrian period 500 million years ago as Fossils of bryozoans were re-identified and revealed to be algae, not animals.

The findings challenge our understanding of animal evolution and the role of algae in Cambrian ecosystems.

Researchers collecting fossils in the Little Rock Dam biota.

Photo by Yang Jie

　　According to the paper, the fossil record reveals the evolution of animals during the Cambrian period, but a type of aquatic moss-like invertebrates, Bryozoa, has been missing from the strata of this period.

In 2021, a paper published in Nature identified a Cambrian fossil from Australia called Protomelission as a type of moss.

However, scholars from China's Yunnan University, Guizhou University and Durham University in the United Kingdom have challenged the identification of bryozoans through a new collaborative study.

Australian Protomelission gatehousei mineralized fossil 1 (Nature 2021 paper).

Photo courtesy of Springer Nature

Australian Protomelission gatehousei mineralized fossil 2 (Nature 2021 paper).

Photo courtesy of Springer Nature

　　Co-corresponding authors of the paper, Martin Smith of Durham University in the UK, together with Zhang Xiguang of Yunnan University in China and collaborators, reconstructed the well-preserved Protomelission-like fossils from the Xiaoshiba Lagerstötte in southern China. According to the research and identification, these fossils are believed to be a kind of benthic, photosynthetic algae, belonging to the order Versicolores.

The results of the study show that no clear Cambrian bryozoan fossils have been found so far.

A new fossil of Protomelission 1 found in the Xiaoshiba Biota shows that this algae is attached to the shell of a brachiopod.

Photo by Zhang Xiguang

The new fossil of Protomelission 2 found in the Xiaoshiba Biota shows that this algae is attached to the shell of a brachiopod.

Photo by Zhang Xiguang

　　The authors also compared the Protomelission-like fossils with the small spinal cord-shaped fossils known as the Cambroclaves, which are widely distributed geographically, and suggested that some Cambrian nails may also be velvet clades.

Together, these findings suggest that benthic biomineralizing algae contributed more to early Cambrian ecosystems than previously thought.

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