Scientists study the homogenization of odd-shoe teeth

Changes in the diversity of the strange hoofs of the new generation in Asia and the degree of pre-tooth molar caries in different branches of the odd hoofs
recently, Ecology and Evolution published online
the results of a collaboration between Bai Bin, Zhang Zhaoqun, Wang Yuanqing, Meng Jin of the American Museum of Natural History and Christine Janis of bristol University. Through the study of the first-level statistics and the degree of molarization of the fossils of the new generation in Asia, the scientists found that the diversity of the new generation of ostentats in Asia occurred in the late Mesocentr (about 39.9 million years ago) by the effect of the gradual decrease in global temperature after the "climate suitability period of the Mesocentr period", rather than the commonly thought of the beginning/aging period (33.9 million years ago).
At the end of the Middle New World, the chiropractin was extinct, the Dai's python fell sharply from four genus to one genus, and the decline in the genus of the rhinoceros was more than half, a phenomenon that may also be applicable to other mammalian groups. Since this apparent diversity decay occurred during the "Ulangochu period" (Asian mammal stages) in the late Meso-Neolithic period, the researchers proposed the "Ulangochu decline".
Against the background of climate change in the new generation of the world, the researchers believe that odd hoofs have a high degree of molarization, and that groups produced by molarization through the sub-tip are more likely to continue into the recent era, such as the genus, rhinoceros, and giant rhinoceros; Most of the groups separated by the front or back tips were extinct before the recent era, such as the extinction of Dai's python at the end of the Middle Neolithic, the extinction of the amphibian and hoofed-toothed rhinos at the end of the New World, and the extinction of the ThunderBolts at the end of the late Neolithic. Therefore, in the 1990s and the 18th, the degree and pattern of the pre-hoof molar molarization are important factors in the development or decline of related groups. By the recent era, the pre-hoof molars had a high degree of molarization, and the evolution of horse and rhino cheek teeth (including front molars) had changed to the increase of the crown and the complexity of the enamel structure, reflecting the ability to resist the abrasion of high-fiber foods and the adaptation to an open, arid environment.
Most of the odd hoof pre-molars in the evolution process have a gradual molarization process, such as the present-day odd hoofs (horses, dragonflies, rhinoceros) have a completely molarized front molars, in order to increase the area of grinding, which is mainly to the mouth to grind food, the intestinal fermentation of the odd hoofs are particularly important; Moreover, the degree and pattern of odd hoof molarization of different groups are not the same, and this study explores for the first time the influence of pre-molar molarization on the evolution and adaptation of odd hoofs.
that the study was funded by projects such as the National
Science Foundation, the National
Pilot Strategy And the Youth Innovation Promotion Association. (Source: Cui Xueqin, China Science Daily)
related paper information: