An animal that is not an animal.
A very particular fossil of 609 million years ago was discovered, it looks like an animal but it is too simple for it to be considered as such.
The animals evolved from unicellular ancestors and then diversified into about 40 different pluricellular anatomical designs, when the transition occurred, is something that we do not know for now, however, this new organism called Caveasphaera suggests that the embryological features that characterize the animals were developed much earlier than the animals themselves.
To reach this conclusion, several specimens measuring approximately half a millimeter were analyzed, of which they had been preserved until their cells, with them since they were of different ages the different phases of the development of the individuals were discovered in the early stages of their life starting with unicellular stages until reaching the cellular pluris.
It has been seen that it is a very simple organism so it does not fit completely in the definition of animal, but the relevant thing here is this development process, since it includes cellular actions, something very characteristic of animal embryos, so we could being before the missing link of a transition that actually had more than one phase.