What's new under the sun? Researchers offer alternative views on how 'new' structures evolve
Freshwater crustacean Daphnia (water flea) is a common research organism in ecology, toxicology, evolutionary developmental biology, and other fields. Credit: Projecto Agua Many crustaceans, including lobsters, crabs, and barnacles, have a cape-like shell protruding from the head that can serve a variety of roles, such as a small cave for storing eggs, or a protective shield to keep the gills moist. This shell (carapace), it has been proposed, did not evolve from a similar structure in a crustacean ancestor, but emerged de novo (or suddenly) through the rather random co-optation of genes that also determine insect wings. However, in a new study from the Marine Biological Laboratory (MBL), Research Associate Heather Bruce and Director Nipam Patel provide evidence for an alternative view: The carapace, along with other plate-like structures in arthropods (crustaceans, insects, arachnids, and myriapods) all evolved. from the lateral toe lo