Late Cenozoic climatic impact on body size evolution in large mammals

• Applicant: Dr. Shan Huang
• Subject Area: Palaeontology
• Term: from 2018 to 2023
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 414011051

Because body size interacts with many fundamental biological properties of a species, body size evolution can be an essential component of the generation and maintenance of biodiversity in relation to the ever-changing environment. Yet, what drives body size evolution at a broad scale remains unclear. In particular, because evolution takes place within the biogeographic setup at the time, to what extent the heterogeneity in environmental condition contributes to shaping the temporal as well as spatial patterns of species body size is a key question for understanding body size evolution; it is also a timely question, given the current biodiversity crisis in the face of projected climate change. In identifying drivers of evolutionary dynamics, the fossil record has played and will continue to play a pivotal role, because extinct taxa are crucial to consider but incorporating them remains a challenge for research approaches relying on extant diversity. To gain a deep understanding of body size evolution, I propose a comprehensive investigation using the fossil record to pinpoint the dominant mechanism linking climate change to body size evolution in large mammals during the last 23 million years. This time period was a history of global climate cooling during which an apparent increase in body size has been observed in many taxa, including two mammalian orders (Artiodactyla and Perissodactyla) based on my recent work. Adding three additional orders of diverse ecological roles and functions (Carnivora, Primates and Proboscidea), and building an interdisciplinary paleontological database containing biodiversity and climatic data across space and time, the proposed project will take several steps further to search for the biological mechanisms that connect climate change to body size evolution. First, I will take a macroevolutionary approach, based on linage dynamics, to assess the influence of climate change on the temporal variation in body size in relation to geographic range dynamics and dietary preferences during the Neogene. Second, I will compare findings of the Neogene dynamics to those in the shorter but climatically more dramatic Pleistocene to provide more relevant knowledge for anticipating the future of the current biodiversity. Third, I will take a biogeographic approach to investigate how taxa of different body sizes are distributed spatially during different times as the global climate changed throughout Neogene and Pleistocene. These three components of the proposed project will complement each other to provide valuable insights into the evolutionary history of mammal body size and shed much light onto the general principles governing the evolution of life.

• DFG Programme: Research Grants