9619545 Hsu PI will be sent specimens of apparently well-preserved mosasaurs from different sites in the U.S. Using methods that she invented, the PI will attempt to isolate DNA and perform PCR and cloning. To avoid the possibility of contamination from her lab, the PI will purchase all new chemicals and lab glassware, and perform all isolation, PCR, and cloning steps in another laboratory that does not have a history of research with lower vertebrate DNA. She hopes to isolate and clone DNA that is definitively not contaminant in origin.