The paleoenvironments and ecosystems of northern China during the Miocene are complex topics, especially concerning the impact of the uplift of the Tibetan Plateau on the surrounding areas and the ecological adaptations of mammals. Our analyses using stable carbon and oxygen isotope analysis, cenograms, and hypsodonty of herbivorous mammals reveal open, arid, savanna-like habitats in the Junggar Basin during the middle Miocene, which subsequently spread to northern China by the late Middle Miocene. Large herbivores, particularly proboscideans and rhinocerotids, exhibited strong adaptations to these open environments. However, smaller taxa maintained a preference for more closed, forested areas. Despite global climate events, faunal diets in the Junggar Basin remained consistent, although biodiversity declined, indicating increased ecological pressure. Our findings contribute to understanding middle Miocene paleoecology in northern China and the adaptive strategies of mammals in response to environmental changes.

The paleoenvironments and ecosystem of northern China during the Miocene are complex issues, particularly because it relates to the impact of the uplift of the Tibetan Plateau on the surrounding areas and the ecological adaption of mammals. Our analyses using stable carbon and oxygen isotope analysis, cenograms, and hypsodonty of large herbivorous mammals reveal arid and open habitats in the northern Junggar Basin, and the different adaptations of mammalian taxa. In the early Middle Miocene, the Junggar Basin witnessed the emergence of savanna habitats characterized by an open landscape. This habitat further spread to northern China during the late Middle Miocene, indicating the widespread distribution of savannas in these regions. This shift is linked to the rapid elevation of the Tibetan Plateau's northern part, accelerating Central Asia's aridification. Our findings enhance our understanding of the Middle Miocene paleoecology in northern China and the adaptive strategies of mammals to environmental changes.

The construction of morphological character matrices is central to paleontological systematic study, which extracts paleontological information from fossils. Although the word information has been repeatedly mentioned in a wide array of paleontological systematic studies, its meaning has rarely been clarified and there has not been a standard to measure paleontological information due to the incompleteness of fossils, difficulty of recognizing homologous and homoplastic structures, etc. Here, based on information theory, we show the deep connections between paleontological systematic study and communication system engineering. It is information, the decrease of uncertainty, in morphological characters that distinguishes operational taxonomic units (OTUs) and reconstructs evolutionary history. We propose that concepts in communication system engineering such as source coding and channel coding correspond in paleontological studies to the construction of diagnostic features and the entire character matrices, which should be distinguished as how typical communication systems are engineered because these two steps serve dual purposes. With character matrices from six different vertebrate groups, we analyzed their information properties including source entropy, mutual information, and channel capacity. Estimation of channel capacity shows upper limits of all matrices in transmitting paleontological information, indicating that, due to the presence of noise, too many characters not only increase the burden in character scoring, but also may decrease quality of matrices. Information entropy, which measure how informative a variable is, of each character is tested as a weighting criterion in parsimony-based systematic studies, the results show high consistence with existing knowledge with both good resolution and interpretability.