Answer:
Exclusive features from Protozoa
Explanation:
Protozoa are unique and complex single-celled eucaryot. So, if the discovered microfossil still has some clues of a presence of a nucleus it might be a feature that can be related with only with a protist organism. Also, some protozoa has special anatomy structures like sensory bristles, photoreceptors, cilia, sting darts, etc. In conclusion there might be some features that could lead researchers to find a new extinct protist organism.