540 Million Years Ago, Deep-Sea Corals Could Create Light
In a groundbreaking discovery, scientists at the Smithsonian National Museum of Natural History have determined that a group of marine invertebrates existing 540 million years ago may have been the first animals to possess the ability to bioluminesce - creating light through chemical reactions - nearly 300 million years earlier than previously thought, according to a report published in the journal Proceedings of the Royal Society B Biological Sciences.
Bioluminescence: An Ancient Communication Tool
Bioluminescence, the ability to emit light, is a widespread phenomenon in nature, with over 94 independent evolutionary origins. It plays a critical role in various behaviors, including camouflage, courtship, communication, and predation.
"What drove its initial evolution in animals has remained an open question," said Andrea Quattrini, co-author of the study and curator of corals at the Smithsonian National Museum of Natural History. "We wanted to find out when bioluminescence first arose, and octocorals represent one of the most ancient animal groups on the planet that can produce light. So, the question became when did they evolve this ability?"
Octocorals: The Oldest Bioluminescent Animals
In 2022, Quattrini teamed up with Catherine McFadden of Harvey Mudd College to create a detailed evolutionary history of octocorals using data from 185 species. Using fossil calibrations and statistical methods, the researchers determined that bioluminescence likely evolved in the common ancestor of all living octocorals around 540 million years ago. Over time, a high proportion of today's octocoral species have retained the ability to bioluminesce, suggesting that it has played an important role in their evolutionary success.
"Our study reveals the oldest known case of bioluminescence on Earth, doubling the previous estimate for its first appearance," said Danielle DeLeo, lead author of the study. "Our findings support the idea that bioluminescence, and light signaling more generally, may have been among the earliest forms of animal communication on the planet. We now know that bioluminescence is an important way for many animals to communicate, especially in the deep sea."