Fossil decapod crustaceans such as crabs, lobsters, and shrimps, have an extensive but understudied fossil record of close to 4,000 species. They originated in the Devonian, but did not become diverse until the Jurassic when they diversified in reef environments and in other environments subsequently. They all share five pairs of legs or 10 in total (hence deca-poda) and two pairs of antennae, but differ vastly across species in many other aspects such as the morphology of the carapace (or sh...
