Washington: Researchers at the University of Missouri and Ohio University have found that dinosaurs had thick layers of cartilage in their joints, which means they may have been considerably taller than previously thought.
"The ends of many dinosaurs`` long bones, which include leg bones such as the femur or tibia, are rounded and rough and lack major articulating structures like condyles, which are bony projections,” said Casey Holliday, an anatomy professor in the MU School of Medicine.
“This indicated that very thick cartilages formed these structures, and therefore the joints themselves, and would have added significant height to certain dinosaurs,” she added.
This study offers new data into how and why reptiles, and mammals, such as humans, build their joints with such different amounts of bone and cartilage.
Holliday and Lawrence Witmer, a professor of anatomy at the Ohio University College of Osteopathic Medicine, determined that the lengths of alligators`` and ostriches`` limbs included between 6 and 10 percent cartilage.
Holliday determined that many theropod dinosaurs, such as Tyrannosaurus, were only modestly taller whereas ornthischian and sauropod dinosaurs, such as Triceratops and Brachiosaurus, may have been 10 percent taller or more.
This indicates that bones don’t always reveal correct information.
“The dinosaur bones mounted in museums don``t accurately reflect what the animals actually had in their bodies in life because the cartilage caps were lost along with the other soft tissues. Knowing how much cartilage was lost allows us to better restore the structure of a living dinosaur bone, which then allows us to better understand how dinosaurs moved and lived,” Witmer said.
Studying the cartilages could also have implications for their speed and posture. While an increase in limb length typically means a taller dinosaur, it could also mean a faster or slower animal, depending on how it affects the skeleton, Holliday said.
From the evidence, Holliday and his research team concluded that certain dinosaurs had a significant amount of cartilage, and thus, were taller than original estimates.
The study is being published this week in the journal PLoS ONE.