Strange life form 500 million years ago was not an animal
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Fossils previously thought to be from prehistoric, tentacled aquatic invertebrates called bryozoans may actually have come from another source – seaweed. This is the conclusion of a new study of 500-million-year-old fossils that takes a fresh look at Protomelission gateshousei fossils, thought to be the oldest bryozoans known.
situation, but also change knowledge about the evolution of the species. To date, these are the only fossils that were not present during the Cambrian explosion, when life on Earth really began to accelerate.
“We tend to think of the Cambrian Explosion as a unique period in the history of evolution when all patterns of animal life were mapped out,” – says paleontologist Martin Smith of Durham University in the UK. “Much of subsequent evolution has been small-scale changes to these original plans. But if bryozoans did indeed evolve after the Cambrian period, it shows that evolution continued on its scale after this critical period of innovation.
The study authors examined tiny P. gateshousei fossils found in the hills of southern China, separate from a batch that was identified as a bryozoan, and found previously unseen signs of soft parts in their samples. These new discoveries make these fossils more apt for green algae in a group known as the Dasycladales, suggests new research, especially in outer membrane features not found in other fossil specimens.
“While previous fossils preserved only the skeleton of these early organisms, our new material showed what lived inside these chambers, — says paleontologist Zhang Xiguang of Yunnan University in China. “Instead of the tentacles that we expected to see in bryozoans, we found simple leaf-shaped protrusions and realized that we were looking not at fossils, but at algae.”
This means that the earliest fossils of bryozoans appeared about 40 million years after the date these fossils were originally dated.
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