What kinds of animals lived during the Proterozoic eon?

During the Proterozoic eon, which lasted from about 2.5 billion to 541 million years ago, the predominant forms of life were simple, multicellular organisms, including early sponges and algae. These organisms were primarily soft-bodied and lacked hard parts, making the fossil record sparse. Toward the end of the Proterozoic, evidence of more complex life forms emerged, such as the Ediacaran biota, which included unique, multicellular organisms that exhibited various body plans. Overall, animal life during this eon was relatively simple and primarily aquatic.