Description of two species of Hoploscaphites (Ammonoidea: Ancyloceratina) from the Upper Cretaceous (Lower Maastrichtian) of the U.S. Western Interior - Landman, Neil H.; Kennedy, William James 1943-; Larson, Neal L.; Grier, Joyce C.; Grier, James W.; Linn, Tom (Bulletin of the American Museum of Natural History, 2019)