ABSTRACT LiveSci in the Valley of the Last Dinosaurs ( http://lastdinos.livesci.org/ ) was a website and social media presence that provided the global online community with unprecedented access to the exciting paleontological research happening in the remote badlands of North Dakota and Montana in the summer of 2016. A collaborative team of researchers, students, and citizen scientists from around the world excavated some of the last dinosaurs that ever walked the Earth, mapped the K/Pg boundary in high resolution, and uncovered fossils that show us how life recovered after the extinction of the dinosaurs. To engage the public in the ongoing process of scientific discovery, dedicated project staff and participating researchers posted videos, photos, blog entries, and social media content nearly every day during the seven-week field season. Researchers and science educators from the Howard Hughes Medical Institute and Denver Museum of Nature & Science, along with collaborators from Brooklyn College, the Smithsonian National Museum of Natural History, Yale Peabody Museum, the Royal Ontario Museum, and the Marmarth Research Foundation, were joined by young scientists and citizen scientist volunteers of all ages. The production team consisted of high school and college interns, public science outreach professionals, and research scientists. To expand the reach of the project, a bilingual intern maintained a parallel Spanish website. Hundreds of thousands of online viewers watched, contributed, and shared these authentic experiences with their communities during the live portion of the project, and many more continue to access the archived website and social media content. This project exemplifies how social media and real-time interaction with scientists have the potential to connect the public to science as it unfolds, removing myths and stereotypes about how science happens and who scientists are. Initiatives such as this one help to create citizens who are more connected to the process of science and who can use that understanding in their lives through more informed decision making.

Intensive collecting of Maastrichtian and early Paleocene plant megafossils (primarily leaves) in the northern Rocky Mountains and Great Plains has resulted in a database of nearly 25,000 specimens from more than 200 localities in eight areas. The most completely sampled section is at Marmarth, in southwestern North Dakota, where 57 latest Cretaceous and 30 early Paleocene localities (11,503 specimens) span the Cretaceous/Tertiary (K/T) boundary. Zonation of the Marmarth megaflora based on floral composition and relative abundance results in four zones: HC I, HC II, HC III, and FU I. This megafloral zonation appears to be applicable to terrestrial sediments across the northern Great Plains and Rocky Mountains and to correlate with the Western Interior ammonite zonation. The zones reflect major megafloral changes before and at the K/T boundary. Megafloral change at the boundary is large (79 percent) and is characterized by the disappearance of most of the Upper Cretaceous dicotyledonous angiosperm taxa. It coincides with a peak in palynofloral extinctions and iridium content and with the occurrence of shocked mineral grains, all of which have become accepted as the characteristic signature of the K/T boundary and as indications of an abrupt causal mechanism. In contrast, the megafloral changes before the boundary appear to have been caused by a regional climate warming. The fact that the megafloral zones are not reflected by palynostratigraphy argues for using an integrated approach to biostratigraphy that combines the high stratigraphic resolution of palynomorphs with the high taxonomic resolution of megafossils. Results of this analysis of the terrestrial plant record are compatible with the hypothesis of a biotic crisis caused by extraterrestrial impact at the end of the Cretaceous.