Supplementary Data from Giant gar from directly above the Cretaceous–Paleogene boundary suggests healthy freshwater ecosystems existed within thousands of years of the asteroid impact

The Cretaceous–Paleogene (K–Pg) mass extinction was responsible for the destruction of global ecosystems and loss of approximately three-quarters of species diversity 66-million-years ago. Large-bodied land vertebrates suffered high extinction rates, whereas small-bodied vertebrates living in freshwater ecosystems were buffered from the end-Cretaceous mass extinction. Here, we report a new species of large-bodied (1.4–1.5 m) gar based on a complete skeleton from the Williston Basin of North America. The new species was recovered 18 cm above the K–Pg boundary, making it one of the oldest articulated vertebrate fossils from the Cenozoic. The presence of this freshwater macropredator within approximately 1.5–2.5 thousand years after the asteroid impact suggests the rapid recovery and reassembly of North American freshwater food webs and ecosystems after the asteroid impact.