Historically, our understanding of the evolution and diversity of extinct species has been based on interpretation of the fossil record. However, over the past couple of decades it has become increasingly easy to access genomic data from fossil specimens up to many tens-of-thousands of years old: so-called "ancient DNA". In this seminar, I’ll discuss several case studies from my own research that illustrate how DNA from ancient animal specimens can help us to more accurately interpret the fossil record. The results are often surprising and may be more broadly instructive for studying the fossil record of much older periods of Earth's history, for which we will never have access to genomic information.