Scientists managed to unravel the riddle of how the exoskeleton of the body of arthropods, which is a rather soft shell, does not collapse over millions of years. Details of the study are published in the journal Geology. The ScienceNOW portal describes them briefly.
Organic matter can persist for a very long time if it contains a high concentration of minerals. Such "long-lived" tissues are, for example, bones. At the same time, fossils of exoskeletons are found in the paleontological layers. They consist mainly of chitin polysaccharide combined with a special type of proteins.
Scientists doing this research, using transmission X-ray microscopy, examined in detail the remains of a scorpion, which is at least 310 million years old. In addition, the remains of a crustacean that lived about 417 million years ago were studied. Crayfish are fossils akin to today's spiders. In the course of research, it was found out that approximately 10% of the original exoskeletons were preserved in the samples. With the microscopic method used, certain types of bonds can be determined, such as connecting proteins and chitin. It turned out that a fairly large percentage of such connections remained in the samples.
As a result of the research, it was concluded that the exoskeletons managed to survive with the help of special waxes that covered the bodies of these arthropods during life. It was these compounds that prevented the drying of animal bodies. After their death, waxes decomposed, and fatty acids became decay products. They are strongly associated with chitin-protein complexes, and the resulting compounds are resistant to degradation.
There is another way to preserve arthropods for a long time. Amber is an important source of knowledge about extinct species. In pieces of amber, scientists have often found many ancient creatures stuck in a viscous liquid. After all, amber is a frozen resin.