You’d probably walk past a chiton without even seeing it. These creatures often look like nothing more than another speck of seaweed on the crusty intertidal rocks. But it sees you. At least, if it’s ...

You’d probably walk past a chiton without even seeing it. These creatures often look like nothing more than another speck of seaweed on the crusty intertidal rocks. But it sees you. At least, if it’s ...

The visual systems of an obscure group of mollusks provide a rare natural example of path-dependent evolution, in which a critical fork in the creatures’ past determined their evolutionary futures.

Diagrams (top) and electron microscope images (bottom) of chiton shells. From left to right: Aesthetes (green) are fount on all chitons, while shell eyes (blue) and eyespots (red) only evolved in a ...