Echinoids (sea urchins) are divided into twomajor groups – cidaroids (a ‘primitive’group)andeuechinoids (a ‘derived’group).Thecidaroidsarea promisingmodelspecies for understanding theancestral developmental mechanisms in echinoids, but little is known about the molecular mechanisms of cidaroid development. In euechinoids, skeletogenic mesenchyme cell… (More)