The study of microscopic structures within the bones of long-extinct vertebrates is leading to new discoveries about the lives of modern animals, according to Holly Woodward Ballard, Ph.D., assistant professor of anatomy at Oklahoma State University Center for Health Sciences.
“We can determine from fossilized bones how old a dinosaur was when it died, how fast it was growing from year to year, whether it was an adult or a juvenile when it died and sometimes if it was male or female,” Ballard said. “We determine this information by looking at modern bone in comparison. To answer questions of the past, we are actually learning more about the animals of today.”
Fossil bones contain much greater detail and information about the lives of extinct animals like dinosaurs than previously believed. Through paleohistology – the study of the microstructure of mineralized tissues in fossil bones – researchers are learning more than ever before.
“We were surprised to find out that so much information can be recorded about an animal’s physiology within their bones,” Ballard said. “By doing this research, I am learning about the past and how these animals lived, but also how their descendants - birds and other vertebrates - live today.”
Researchers take slices of fossilized bones and polish them down to the thickness of a standard sheet of paper. With light shining through the slice, researchers can analyze the microstructures with high-powered microscopes.
“What you see when you look through the microscope is that all the detail is preserved,” Ballard said. “We can see holes where blood vessels used to be, pits where bone-secreting cells used to live and the fiber orientation of the fossilized bone. We can tell a great deal more about how the dinosaur lived than we could tell just by looking at the bone itself.”
Researchers then compare what is known from the analysis of bone microstructures of modern animals with that from fossilized bones, particularly dinosaurs, and use those comparisons to infer how the ancient animals lived.
Ballard used these methods while researching the life of Maiasaura peeblesorum, the “good mother lizard,” that lived millions of years ago in Montana. She and three other researchers recently published a study providing the most detailed reconstruction of dinosaur life history ever released. The work was featured in Paleobiology, the quarterly journal of the international Paleontological Society.
“By looking within the bones, and synthesizing what previous studies revealed, we now know more about the life history of Maiasaura than any other dinosaur,” said Ballard. “Our study makes Maiasaura a model organism to which other dinosaur population biology studies will be compared.”