ISO Fellow Dr. Darin Croft and colleagues Russell K. Engelman and Federico Anaya have just published a description of some new South American marsupials from middle-Miocene Bolivia, including two new species of Palaeothentes, P. serratus and P. relictus, hailing from approximately 13 million years ago. Engaging in what amounts to a bit of paleo-dentistry, Croft and his colleagues analyze fossil tooth shape and construction in their quest for information regarding the animals’ eating habits, lifestyle, and genetic evolution, and, ultimately, extinction.