This text was initially featured on Hakai Journal, an internet publication about science and society in coastal ecosystems. Learn extra tales like this at hakaimagazine.com.
Sixty-nine million years in the past, an asteroid practically 10 kilometers broad slammed into what’s now the Yucatan Peninsula in Mexico. The affect lit huge stretches of the planet on fireplace. Soot and dirt choked the Earth. Because the world burned, temperatures within the ocean plummeted, and creatures that when dominated, together with ammonites, plesiosaurs, and mosasaurs, died out—together with 80 % of the opposite animal species on the planet.
Within the void, new life flourished.
Inside three million years, new fish species have been thriving on a reef of coral-like algae and enormous tuberous clams simply 500 kilometers from the asteroid’s crater. At some point, one in every of these fish—with an elongated snout and a fragile, slender physique—died. It sank to the sandy seafloor the place, together with different animals, the imprint of its skeleton was compressed into limestone.
The ocean receded and, within the seventh century, Maya builders establishing temples within the metropolis state of Palenque started quarrying fossil-studded rocks from the now-dry seabed. The petrified creatures got here to tell Maya beliefs a couple of earlier world destroyed by fires and floods. One slab imprinted with fish was introduced into the palace, the place it was painted and adorned with plaster. Palenque’s residents used different fossils, together with megalodon enamel and stingray spines, as reducing instruments or buried them with the useless.
However the skeleton of the long-snouted fish remained buried within the quarry.
When Palenque, like many Maya metropolis states, collapsed within the tenth century, its temples and their fossils have been deserted and swallowed by the forest. They lay forgotten till Spanish colonists started finding out the location within the 1800s. However it wasn’t till the 2000s that researchers examined the impressions within the limestone extra intently.
The fish fossils present in Palenque have been from species that had by no means been seen earlier than. “It was similar to a film script,” says marine biologist David Bellwood at James Cook dinner College in Australia, who was introduced in to assist establish the fossilized fishes. “We discovered them on the lids of tombs.”
However the extra surprising discovery got here after paleontologists traced the limestone again to the quarry from which it was initially unearthed.
There, after millennia buried in stone, the long-snouted fish lastly noticed gentle—and upended our understanding of fish evolution.
Researchers recognized the fish as a flutemouth, a species whose descendants reside on fashionable coral reefs. Dozens of different fossils pulled from the quarry included two different households of reef fishes: damselfish and grouper.
Bellwood and his colleagues present in a new research that these fossils symbolize the earliest recognized examples of reef fishes discovered wherever on Earth. As we speak, we consider grouper, flutemouth, and damselfish as coral reef fishes. However these teams truly emerged in a world earlier than fashionable coral, which wouldn’t arrive on the scene for an additional 29 million years.
Earlier than this discovery, the oldest proof of reef fishes was from about 50 million years in the past: fossils pulled from what’s now Monte Bolca in northern Italy. Based mostly on the range represented in these Italian fossils, some scientists suspected that reef fishes doubtless emerged earlier—nearer in time to the asteroid affect. However no fossils from that interval had ever been discovered. The specimens from the Palenque quarry, which date from between 65 and 63 million years in the past, assist fill in that hole.
Though grouper, flutemouth, and damselfish are the one present households represented within the Palenque fossils, Bellwood thinks most different reef fishes doubtless advanced across the identical time. The research additionally means that reef fishes emerged within the western Atlantic Ocean, relatively than the traditional Tethys Ocean, close to present-day Italy, as scientists had thought.
“These fossil deposits are actually vital for understanding the historical past of coral reef fish,” says David Wainwright, an evolutionary biologist on the College of California, Davis, who was not concerned within the analysis. Wainwright notes that this research doubtless isn’t the ultimate phrase on the origins of reef fishes. “We in all probability will finally discover one other fossil that’s even older,” he says—perhaps even one from earlier than the asteroid hit.
Bellwood, for his half, is worked up about what should still lie hidden within the Palenque quarries. Future excavations may yield much more fossils that additional unravel the historical past of coral reef ecosystems. “Theoretically, there could possibly be all types of fossils in there,” he says. “It may simply be a magical little location.”
This text first appeared in Hakai Journal, and is republished right here with permission.