A complete lophophorate fossil, dated at 518 million years old, has been discovered in China. Their study reveals that it was a plateworm with a mobile lifestyle, unlike the three extant animal lines of today’s lophophorates of which it is likely the ancestor. It allows this group to be brought closer to that of the annelids.
The Cambrian geological period, more than 500 million years ago (Ma), is an important time because the first fossils of many groups of animals are known there. Some of them are enigmatic due to their strange appearance and the small number of fossils found. This is the case of the tommotidae, an extinct subgroup belonging to the lophophora, some of whose current representatives resemble shells called brachiopods. The precise morphology and relationship of some tommotids to other groups of animals remains obscure.
But paleontologists have discovered a complete tommotiid fossil in Chengjiang (China) dated 518 Ma. This discovery is published in the journal current biology September 27, 2022 sheds more light on the place of representatives of this group in the animal kingdom and better understands how animals diversified more than 500 Ma ago.
A tiny “phoenix” from the ancient seas
Here’s a phoenix… even if it doesn’t look like much! In any case, this is where the name of this new fossil species is taken: Wufengella bengstoni ; “wufeng“which means” dancing phoenix “. This fossil shows that, during its life, the animal was small: less than 2 cm long. Certainly small, but rare, the fossil is almost complete! It allows us to know that it was a strange worm formed by segments -metameres- covered in the middle of the back by two sets of asymmetrical plates, and a series of small plates on each side of the back.
These plates do not have any particular ornamentation, apart from the growth striae that allow us to determine how these plates developed during the growth of the animal. But could it have wings like the phoenix? Almost ! Well, not wings, but fine bristles made of chitin. setae – lining the sides of the worm, preserved as tracks or sometimes as masses of pyrite. “looks like p[…]