Are Insects and Crustacea related?
According to the Pancrustacea hypothesis, which is supported by some molecular and anatomical evidence, both Crustaceans and insects evolved from a common ancestor; or alternatively, insects evolved from an unknown crustacean (presumably as marginal marine and amphibious forms during the Silurian) The main problem with the Pancrustacea theory is the lack of transitional forms, especially in the fossil record. For this reason many prefer the rival Atelocerata theory (Myriapoda and insects share a common ancestor independent of Crustacea).
