Water bear insects (scientific name: Tardigrades), the strongest creature on the surface, are not only resistant to radiation, water shortage, and high temperature, but they can also survive being shot by a gun. The water bear has experienced five major extinction events in the Phanerozoic. Even if it survives to this day, there is still very little knowledge about it. However, researchers have discovered a new species of water bear in Dominican amber. Help us unveil a new veil of the strongest species.
The modern-looking water bear was first discovered in the Cretaceous period 80 million years ago. Although the water bear has a long evolutionary history and a wide global distribution, there are very few fossil records because its size is too small and its body is difficult to mineralize. The chance of fossils is quite small.
The latest paper in the British scientific journal “The Royal Society Report Series B” pointed out that researchers have discovered a new, modern-looking water bear fossil, bringing new “genus” and new “species” at the same time.
This new fossil is called Paradoryphoribius chronocaribbeus, which is the third water bear worm amber fossil that has been fully documented and officially named so far. The other two fully documented and modern appearance water bear worm fossils are Milnesium swolenskyi and Bearn leggi, from North American chalk. Ji’s amber.
Paradoryphoribius is different from the other two fossils. It is the first fossil to be found embedded in Miocene Dominican amber 16 million years ago. It is also the first water bear/tardigrades. The representative fossil of the superfamily Isohypsibioidea.
Unique foregut tissue, water bear fossils bring new genus
Professor Phillip Barden of New Jersey Institute of Technology, one of the authors of the study, discovered this fossil in the laboratory and worked with lead author Marc A. Mapalo and senior author Javier Ortega-Hernández to study this fossil together.
Mapalo pointed out that the difficulty in processing this amber specimen is that a dissecting microscope is generally used, and the transmitted light can see larger forms of insects and spiders in the amber, but the total length of the body of Paraadoryphoribius is only 559 microns. For a dissecting microscope It’s too small, so a special microscope is needed to see this fossil completely.
Fortunately, the stratum corneum of the water bear is composed of chitin, a fibrous glucose substance that is the main component of the cell wall of fungi and the exoskeleton of arthropods. Chitin is fluorescent and easily stimulated by lasers, so fossils can be observed with a conjugate focus microscope. Through this special microscope, Mapalo discovered important features lurking in the fossils, namely the paws and oral devices, as well as the foregut tissue composed of the stratum corneum.
Although it looks like a modern water bear worm from the outside, it can see the unique foregut tissue through a special microscope. Mapalo pointed out, “This discovery gives us reason to establish a new genus in the Tardigrades superfamily. Paradoryphoribius is the only genus in the Isohypsibioidea superfamily with this characteristic.”
Ortega-Hernández said that water bear fossils are very rare. In the new study, the complete sample includes only 4 specimens, of which only three have been officially recorded and named, including Paradoryphoribius. Paraadoryphoribius also provides the only information about the water bear cheek device. material.
The future does not rule out looking for water bear fossils from amber
From experience, water bears are small in size, have unique preferences for specific habitats, and have a higher probability of preservation in amber. Therefore, amber sediments may be a good source for finding new water bears fossils. Therefore, scientists believe that, The amber sediments of Burma and the Baltic Sea may also contain water bear fossils, although it is not easy to find them. In addition, the water bear fossils are too small to see them even if they are preserved.
Mapalo believes that if you only look at the appearance of the water bear, you will think that there is no change in its body. However, through observation under a professional microscope, it is found that there are characteristics in the fossils that are not observed in the existing species, which will help scientists to learn more. Understand what has changed in the water bear insect’s body in tens of thousands of years.
Remarks: In terms of items and subjects, “Super” (Super) can sometimes be added, such as categories such as Superorder and Superfamily.
(The source of the first image: shutterstock)
