Muscle Reconstruction

Most theropod dinosaurs were bipedal and predatory, which means they ran around on two legs and hunted other animals for food. Since they didn't use their forelimbs for walking on they could use them for other tasks, but what those were we're not really sure. Some theropods eventually specialized their forelimbs for flight and evolved into birds, but many others had forelimbs that were unique and varied in shape and size. My research has been interested in what these theropods were doing with their forelimbs, and how we might be able to tell that from the shape of their bones. To do that, I start by reconstructing the musculature of the forelimb based on the arrangement of the muscles in dinosaur's living relatives. When we look at how the musculature has evolved along the theropod lineage, we can understand how it relates to potential functions like prey capture.


Forelimb Evolution & Morphometrics

Another way to try to understand theropod dinosaur forelimb function is to look at how the size and shape of the forelimbs have evolved over time. I use phylogenetic comparative methods such as phylogenetic generalized least squares and Ornstein-Uhlenbeck modeling to investigate trends in theropod forelimb size and to identify evolutionary convergence in different theropod groups.

I use geometric morphometrics, which involves capturing the shape of the bones by digitizing the outline in xy-coordinates, to investigate how forelimb shape is tied to size and prey size preference in both cats and theropod dinosaurs. To understand how fossil animals moved and behaved, paleontologists use both living close relatives as well as animals that aren't closely related but perhaps have a similar way of life. In the case of theropod, it is tough to identify a modern animal that uses their forelimbs like theropods might have because there are so few modern bipeds that aren't birds (who use their forelimbs mainly for locomotion: flight). Even though they are quadrupedal, modern day cats do use their forelimbs in capturing their prey, and our understanding of the relationship of their forelimb shape to the kinds of prey they eat may provide information that is also applicable to theropods.



I have had the pleasure of participating paleontological field expeditions in a wide variety of locations and time periods, including the Jurassic of Wyoming, the Cretaceous of China, the Cretaceous and Oligocene of Tanzania, and the Cretaceous of Madagascar.