16-million-year-old tardigrade found preserved in amber

Although it turned out to be difficult to spot, scientists managed to find a small tardigrade trapped in a piece of Dominican amber. Unprecedented discovery of ancient tardigrade sheds new light on this remarkably enduring group of microscopic animals.

About 16 million years ago, a single drop of tree resin managed to capture a fragment of a flower, three ants, and a beetle. It’s an awesome booty, but more remarkable still, the resin has also trap a capricious tardigrade. The resulting piece of amber is only the third known tardigrade fossil and the first Late Cenozoic fossil, the current era that began 66 million years ago with the extinction of all non-avian dinosaurs.

The fossil was found in La Cumbre in the Dominican Republic, a region known for its vast deposits of amber. Researchers at the New Jersey Institute of Technology and Harvard University had already studied the piece of amber for months before spotting the half-millimeter-long creature tucked away in a corner. In a press release, lead author Phil Barden describe as a discovery “once in a generation”. Discovery Details Now appear in the scientific journal Proceedings of the Royal Society B.

Tardigrades are among the most resilient creatures on Earth. Eight-legged invertebrates are known to shrug their shoulders besides the effects of extreme dehydration, bitterly cold temperatures and harmful radiation. They can to survive being shot by a gun (to some extent), and their walking skills compete with those creatures 500,000 times their size. Tardigrades, also known as water bears and moss piglets, are ancient organisms that appeared around 500 million years ago and survive no less more than five mass extinctions. Very few animals on Earth can Claim such an impressive resume.

“What is so remarkable is that tardigrades are an ancient ubiquitous lineage that has seen everything on Earth from the fall of dinosaurs to the rise of terrestrial colonization of plants,” Barden said. “Yet they are like a ghost line to paleontologists with almost no fossil record. Finding late-grade fossil remains is an exciting time where we can empirically see their progression through Earth’s history. “

Analysis of the fossil revealed some distinct physical characteristics, justifying the declaration of a new species and a new genus. The tardigrade was named Paradoryphoribius chronocaribbeus, which mixes “chrono”, the Greek word for time, and “caribbeus”, for the region in which the fossil was found. The specimen is a relative of the modern tardigrade superfamily Isohypsibioidea, according to research.

Scientists say it is the best-represented tardigrade fossil to date. The team were able to see very fine details including internal structures, mouthparts and needle-like claws dozens of times thinner than human hair.

For the first time, scientists have successfully visualized “the internal anatomy of the foregut in a tardigrade fossil and found combinations of characters in this specimen that we don’t see in living organisms now”, Marc Mapalo, the main author of the article. and a graduate student from Harvard’s department of organic and evolutionary biology, said in the press release. “Not only does this allow us to place this tardigrade in a new genus, but we can now explore the evolutionary changes this group of organisms has undergone over millions of years.”

Barden said they “always scratch the surface” when it comes to understanding the evolutionary history of tardigrades. It’s a rare find, but the find shows scientists should look very carefully at even the smallest spots when studying amber fossils.

Following: The strangest amber fossils ever discovered.