DNA from the retinas of lungfish, the closest living relatives to the first terrestrial vertebrates, is closer to retinal DNA from land animals than to retinal DNA from fish. The first land creatures thus probably had decent color vision. Steve Mirsky reports.
Look before you leap, the old adage has it. Well, it seems that the animals that first ventured out onto the land from the sea were well equipped to look when they made that leap. Researchers studied the retinas of the eyes of lungfish, which are thought to be the closest living relatives to the first vertebrates that lived on land. Lungfish use gills to take in oxygen, but can also breathe air if necessary. And they live in shallow freshwater habitats with a lot of light. So it would make sense that they could see pretty well in a nearly terrestrial environment.
And indeed, DNA in the genes for visual pigments in the retinas of the lungfish turned out to be much closer to the sequences found in four-legged animals than with other kinds of fish. The work appears in the journal Biomed Central Evolutionary Biology.
So the early land-dwellers were probably pre-adapted to seeing well in their new environment, which must have come in handy for finding food and mates. How did the first creatures that crawled out of the sea smell? Probably pretty bad.