The tardigrade trapped in amber is an unprecedented species

Scientists discovered an incredibly rare fossil floating in amber 16 million years ago.

today tardigradeAlso known as tardigrades and moss piglets, they can be found in almost any environment with liquid water, from the depths of the ocean to the thin film of water that covers the moss on land. Small creatures are famous for their survival skills. Tardigrades drain most of their water from their body and significantly slow down their metabolism, resulting in a state that resembles interrupted animation that can withstand extreme temperatures, pressures, and radiation.

However, while tardigrade are almost impossible to destroy when alive, few tardigrade fossils have been found so far due to their small size and lack of hard tissue. To be exact, there are only three. Two of these fossil species found in Canada and New Jersey are officially named. The other was discovered in Western Siberia and has no name.

Related: 8 reasons to love tardigrades

But now, in a new study published in the journal Tuesday, October 5 Royal Society Bulletin B: Biological SciencesScientists have introduced a new species of tardigrade found in amber from the Dominican Republic. The fossils date back to the Miocene (23 to 5.3 million years ago) and are so well preserved that the team was able to place the newly discovered tardigrades. Paradoryphoribius chronocaribbeus, In the tardigrade “Tree of Life”.

“There are actually only two Tajgrads apparent from the fossil record,” said Frank Smith, developmental biologist and assistant professor at the University of North Florida. Noted. Florida is not involved in any new research. According to Smith, the quality of the fossils allowed researchers to apply the same techniques used to identify living tardigrades, and the team said the newly discovered species was a modern tardigrade. It helped me determine how they were related.

Tardigrades are less than 0.02 inch (0.6 millimeter) long, how did the researchers find them? Lead author Mark Maparo, a doctoral student in the department of bioevolutionary biology at Harvard University, told Live Science.

Mapalo collaborators at the New Jersey Institute of Technology first obtained amber and searched for ants captured in the material. The team led by evolutionary biologist Phillip Barden evolution Social insects such as ants and termites.

“They had amber for months, but they only looked at ants,” Maparo said. However, at one point, the keen-eyed lab members noticed a large caterpillar shape with legs with small claws protruding from below. Behold, they found a tardigrade floating on amber, next to three ants, a beetle, and a flower.

“They were luckier to see it… because it was not what they were looking for,” Maparo said. Knowing about the fossils, Maparo said he was “really surprised” as he was very unlikely to find a tardigrade fossil. As a water lover, he is very late. Once wrote a song about themHe was eager to discover one of the few known tardigrade fossils.

In addition to finding the fossils, the team was fortunate enough that the tardigrades were sitting fairly close to the surface of the amber. In other words, the light from the microscope could easily reach the sample. Using a technique called transmitted light and confocal fluorescence microscopy, the researchers used several external anatomical structures, such as Taj-grade claws, and various rigid structures found in the foregut of living creatures. I have examined the two internal morphologies.

Related: Ancient imprints on little “vampires”: eight rare rare fossils

“This is the first tardigrade fossil that was able to visualize its internal morphology,” Maparo said.

Based on the shape and location of the tardigrade’s claws, researchers identified tardigrades as part of the superfamily Isohypsibioidea, a diverse group of modern tardigrades. P. Chrono Caribbean The oldest known member of the superfamily.

However, aspects of the water bear’s internal structure set it apart from the associated tardigrades. In particular, the hard structure between the mouth and the esophagus, called the macropracoid, has a unique shape. Other members of Isohypsibioidea have a few thick macropracoids, but the new tardigrade fossil was just one thin, crested one.

“For this reason, it does not match the existing genres within this superfamily,” Maparo explains. And for this reason, the team created new genera and species to accommodate it. P. Chrono Caribbean.

At its peak P. Chrono Caribbean According to Smith, he’s probably hanging from a foam pad, swallowing fluid from plant cells, much like a modern tardigrade. “If we went back to this place 16 million years ago, we would probably find this species everywhere. And, in theory, more to Dominican amber in the same region and to other amber deposits in the world. He said many amber fossils could be hiding.

Currently, few people are looking for amber tardigrade fossils, so more scientists could find more tardigrade fossils, Maparo said. ..

To the naked eye, “I don’t even know if that looks like dust spots, probably not at all,” Smith said. Therefore, in order to find large sea creatures, scientists must carefully inspect all amber samples under a microscope. But generally speaking, “if you find amber, you’ve probably lived near the tree that produces amber … so it’s worth looking at a sample of the amber color of tardigrade.” Noted.

Until more tardigrade fossils are found, Maparo plans to study the genetic and molecular mechanisms that lead to the growth and development of living tardigrade. He is currently visiting Smith’s laboratory in Florida to study the development of tardigrade claws. This series of studies could help clarify the driving forces behind the evolution of tardigrades, which led to the adoption of the familiar plump body plans we now know and love. to augment.

In addition, Maparo wants to study the first tardigrade fossil ever discovered at Harvard. Fossil identified as a species Leggi from BeornWas discovered near Cedar Lake in Manitoba in 1964 and is approximately 78 million years old. Upper Cretaceous, The author writes in his report. However, the exact relationship between tardigrades and modern species has not yet been determined, as high-resolution imaging technology was not available at the time.

Originally published in Live Science.