A comb jelly fossil from some 500 million years ago shows a previously unknown species of these ancient sea animals that had a more complex nervous system than their modern descendants.
Evolutionary theory doesn’t preclude the possibility of organisms becoming simpler over geological time, but it’s a relatively uncommon phenomenon. Examples are mostly limited to ancient arthropods, sea lilies, and brachiopods – also known as lamp shells.
“Comb jellies occupy a much earlier position in the animal tree of life [than arthropods and brachiopods], so it is filling …
Read more at New Scientist