Related Experiment Videos
Mammal extinctions, body size, and paleotemperature
T M Bown1, P A Holroyd, K D Rose
1U.S. Geological Survey, Federal Center, Denver, CO 80225.
Summary
Fossil mammal tooth size in the Eocene Bighorn Basin inversely correlated with paleotemperature. Warmer periods saw smaller mammals, while colder periods favored larger species, influencing faunal turnover.
Area of Science:
- Paleontology
- Paleoclimatology
- Mammalian Evolution
Background:
- Body size in fossil mammals is a key indicator of environmental conditions.
- The early Eocene epoch experienced significant climatic fluctuations.
Purpose of the Study:
- To investigate the relationship between paleotemperature and fossil mammal body size.
- To understand how climate change influenced faunal dynamics, including extinction and immigration patterns.
Main Methods:
- Analysis of the natural logarithm of tooth area as a proxy for body size.
- Correlation of body size data with paleotemperature records from the Bighorn Basin.
- Examination of faunal turnover events in relation to temperature trends and sediment accumulation rates.
Main Results:
- A significant inverse relationship was observed between tooth area (body size) and paleotemperature.
- Warmer temperatures correlated with smaller mammal tooth areas, while colder temperatures correlated with larger tooth areas.
- Paleotemperature trends drove local and regional extinction and immigration patterns, leading to faunal turnovers.
Conclusions:
- Climate change, specifically paleotemperature fluctuations, played a crucial role in shaping mammalian body size and faunal composition during the early Eocene.
- Reversals in temperature trends led to the extinction of both small and large-bodied species.
- Sediment accumulation rates modulated the observed faunal turnovers.