Flight Loss, Underdetermination, and the Origin of Birds: A Case Study of the Oviraptorosauria

What if fossils of “feathered theropod dinosaurs” are instead misidentified secondarily flightless birds? Flight loss induces anatomical transformations that make bird species appear misleadingly primitive while obscuring their true evolutionary relationships. What would this imply for the popular consensus that birds are simply living dinosaurs? We explore a well-documented group with unambiguous feathers, the Oviraptorosauria, in an empirical case study of this problem using a skeptical theoretical and methodological framework. Our study emphasizes how conflicting data are mutually consistent with, and therefore underdetermine, alternative hypotheses for the origin and early evolution of birds. This work is intended to engage a wide range of researchers in evolutionary biology and the history and philosophy of the sciences, and addresses issues intersecting all these disciplines. In adopting a wider perspective for insights into the origin and early evolution of birds, we hope to stimulate multidisciplinary investigation of this complex problem in evolutionary history.