When you were a child, you may have learned that you can count tree rings to find out how old the tree is. Biologists and forensic scientists use a similar concept but with teeth. They count cementum rings in teeth to determine the age of an animal. Recently, scientists have taken this technique a step further by using high-powered X-ray imaging to study ancient fossils. This method not only helps determine the age of the fossilized creature but also provides insights into their growth and development.
The idea of using X-ray imaging to study fossilized teeth came about when Ian Corfe was examining shrew teeth at the European Synchrotron Radiation Facility in France. His former supervisor, Pam Gill, had been studying mammaliaforms for years. Mammaliaforms are small creatures that bridge the gap between mammals and their ancestors. Gill wondered if synchrotrons could reveal the rings in ancient fossil teeth. Corfe conducted a scan of a sample from the early Jurassic mammaliaform Morganucodon and discovered that the increments in the teeth were preserved after nearly 200 million years.
Corfe shared this data with Gill, who was supervising Elis Newham’s graduate work at the time. They decided to explore the potential of using this technique on other fossils to understand not only the age of the creatures but also their developmental patterns and life histories. Through subsequent scans, they found that early mammals had relatively long lifespans based on the size and gaps between the cementum rings. These early mammals grew rapidly as juveniles, but their growth slowed down at a much later stage than modern small-bodied mammals.
The findings challenge previous assumptions about the life histories of early mammals. Despite having traits that we associate with modern mammals, such as single tooth replacement and fur, early mammals took longer to reach sexual maturity compared to small-bodied mammals today. This discovery sheds new light on the evolutionary history of mammals and how their growth patterns have evolved over time.
Overall, the use of X-ray imaging on fossilized teeth has revolutionized the way scientists study ancient creatures. By analyzing cementum rings, researchers can not only determine the age of the fossils but also gain valuable insights into their growth and development. This innovative technique has opened up new possibilities for understanding the evolutionary history of mammals and how they have adapted over millions of years.
In conclusion, the study of tooth rings in fossilized teeth using X-ray imaging has provided groundbreaking insights into the growth patterns and life histories of ancient mammals. This research challenges previous assumptions and offers a new perspective on the evolution of mammals over time. By combining cutting-edge technology with traditional methods of analysis, scientists are uncovering hidden secrets locked within ancient fossils.
