WASHINGTON (AP) — Many animals can glow in the dark. Fireflies famously blink on summer evenings. But most animals that light up are found in the depths of the ocean.
In a new study, scientists report that deep-sea corals that lived 540 million years ago may have been the first animals to glow, far earlier than previously thought.
“Light signaling is one of the earliest forms of communication that we know of — it’s very important in deep waters,” said Andrea Quattrini, a co-author of the study published Tuesday in the journal Proceedings of the Royal Society B.
Many deep-sea soft coral species light up briefly when bumped — or when stroked with a paintbrush. That’s what scientists used, attached to a remote-controlled underwater rover, to identify and study luminous species, said Steven Haddock, a study co-author and marine biologist at the Monterey Bay Aquarium Research Institute.
But how long have some coral species had the ability to glow?
To answer this question, the researchers used genetic data from 185 species of luminous coral to construct a detailed evolutionary tree. They found that the common ancestor of all soft corals today lived 540 million years ago and very likely could glow — or bioluminescence.
That date is around 270 million years before the previously earliest known example: a glowing prehistoric shrimp. It also places the origin of light production to around the time of the Cambrian explosion, when life on Earth evolved and diversified rapidly — giving rise to many major animal groups that exist today.
“If an animal had a novel trait that made it really special and helped it survive, its descendants were more likely to endure and pass it down,” said Stuart Sandin, a marine biologist at the Scripps Institution of Oceanography, who was not involved in the study.
