ABOVE: Illustration of Diretmus argenteus
WIKIMEDIA, EMMA KISSLING
For a fish with such a remarkable retina, the silver spinyfin has a rather modest appearance: its body is a small, flattened, disc bearing a frowning mouth and a ridge of short, bony spines along its belly. But its large, impressive eye, researchers report today (May 9) in Science, has earned Diretmus argenteus the honorable title of vertebrate with the most types of visual opsins—the light-sensitive proteins that form the basis of photoreceptor cells of the retina. These likely help the swimmer see in the dark, hundreds of meters below the sea surface, where it spends most of its life.
Human retinas have four types of visual opsin: three present in cone cells, which allow us to see blue, green, and red, and one in rod cells, which enables vision in dim light. The silver spinyfin produces up to 14 visual opsins in ...
