How to Grow a Dinosaur

2013 REU Project:

Dinosaurs evolved in the Triassic period of Earth history, about 230 million years ago, and took over the terrestrial environment soon after. Even though dinosaurs are a unique group, they inherited many of their characteristics from their closest relatives. Some of these characters include a fast growth rate and new sites of muscle attachments on bones. Yet, the order of the appearance of these characters among early dinosaurs and their closest relatives and the relationships of the appearance of the muscle scars and individual age (ontogeny) are not clear. To understand the growth of an animal, different growth stages of a single species are needed, but such growth series rare in the fossil record. Fortunately, researchers at the Field Museum have recently collected hundreds of bones of different sized individuals of close dinosaur relative named Asilisaurus kongwe, from the Middle Triassic of Tanzania in Africa. The bones of Asilisaurus will help us understand the relationship between growth and the appearance of dinosaur-like features.

Research methods and techniques: An REU intern will focus on the skeletal remains of Asilisaurus by examining and describing gross morphology of bones of various growth stages of the dinosaur relative. This will be accomplished by sorting hundreds of bones of Asilisaurus that have come straight from the field. In addition, the intern will create histological sections (cross sections) of long bones (e.g., femur) in order to compare the appearance of external bone features with internal bone features at different sizes. These results will then be compared to bone features and growth trajectories of early dinosaurs.

Curator/Advisor: Dr. Kenneth D. Angielczyk (Assistant Curator of Paleomammalogy, Geology) and Dr. Sterling J. Nesbitt