"Researchers at Durham University, UK, and Northwest University, Xi'an, China, examined 15 exceptionally preserved fossils of the #annelid #worm #Iotuba #chengjiangensis dating from the early #Cambrian period 515 million years ago.

The fossilized remains included evidence of the worms' guts and kidneys and revealed they had an unexpectedly complex structure similar to that of other #annelid #worms."

https://phys.org/news/2023-01-ancient-fossils-evolution-sea-worm.html