What were the first animals? The fierce sponge–jelly battle that just won’t end

Key Points

• The evolution of early metazoans reveals a significant conflict between sponges and jellyfish.
• Phylogenetic analysis indicates that sponges and jellyfish share a common ancestor but diverge in their development.
• This evolutionary investigation examines how the sponge-jelly battle influences diversification of early animals.
• Understanding this conflict highlights the complexity of animal evolution and ancestral relationships.