Starlet Sea Anemone

The starlet sea anemone (Nematostella vectensis) is a small, burrowing anemone of salt marshes and estuaries on both sides of the North Atlantic and the Pacific coast of North America. It has become a model organism for how animal body plans evolved.

🧬 Field Guide Specimen: Open Sea Anemone in the CRV Science Field Guide to log the specimen, see its place among the Cnidaria+Ctenophora lineages in the Cladogram Explorer, and test your recall in the Red List conservation game.

The genome, published in 2007, showed that this simple-looking animal has a gene repertoire and gene organization close to those of vertebrates, including many genes thought to be bilaterian inventions. This implies that the common ancestor of cnidarians and bilaterians was genetically more complex than expected. See Gene.

Although anemones look radially symmetrical, Nematostella has a second body axis marked by the expression of Hox-like genes, giving it a hint of bilateral symmetry. This makes it useful for studying how the bilaterian body plan arose.

The animal is transparent as an embryo, produces thousands of eggs on a light cycle in the lab, and can regenerate after being cut. Its small size and short generation time suit experiments.

• Evolutionary developmental biology — body plan evolution
• Gene expression — how genes pattern the embryo