Not only is amber popular as jewelry, but it is also popular with paleontologists: when it was formed, the resin of the fossilized tree regularly included animals or parts of plants that have remained in it to this day. The finds from China’s Zhangpu region are particularly rich, as a team led by Bo Wang of the Nanjing Institute of Geology and Paleontology evaluated some 25,000 specimens of amber with fossils and 5,000 other plant fossils and put them together to create a picture of the ecosystem at the time. The group has published their study in “Science Advances”..
According to Wang and Co, the collection is the richest of any tropical rainforest ecosystem to date. Combined with large animal fossils, it shows exceptional biodiversity in a 14.7 million-year-old forest from the Miocene. Wang’s group found the leaves of 78 species of trees as well as many seeds of dioecious plants and legumes, which still dominate the rainforests of Southeast Asia to this day. At that time, their distribution reached the north in a warmer world.
The invertebrates in the group are considered the richest in species: scientists have counted representatives of 250 families of spiders, moths, millipedes and other arthropods, as well as representatives of 200 families of insects. Therefore, the site is indeed one of the four species-richest amber deposits on Earth. The insect fauna of Zhangpu includes ants, stick insects, termites, and grasshoppers, which are now restricted to the tropics of Southeast Asia and New Guinea. Many species also belong to the genera that are still in existence.
The scientists wrote that the results showed that the populations of Asian insects in the rainforests have remained the same since the Miocene. And they demonstrated that the relative environmental stability of these forests also ensures that the number of species increases over time. This makes them more valuable than we expected.
Wang’s team suggests that the emergence of tropical forests in Zhangpu was likely related to warmer winters in the area than they are today. As a result, conditions were relatively stable throughout the year.