Baculites Baculus Meek and Hayden, 1861 (Earliest Maastrichtian) from the Uppermost Pierre Shale in the Raton basin of Northeastern New Mexico and its Significance

Morphometric analysis of the Late CretaceousPlacenticerasof Alabama, USA: sexual dimorphism, allometry, and implications for taxonomy

“…The locality information associated with 36 (18%) of our studied specimens suggested a Maastrichtian occurrence, but these localities are either poorly documented, expose both Campanian and Maastrichtian strata, or are located downstream from sites exposing Campanian strata, suggesting the possibility of modern downstream transport of older fossil materials. Almost all previous reports of Maastrichtian Placenticeras have since been revised to a Campanian age (see Supplementary Text), although a recent study reports P. meeki and P. costatum from the earliest Maastrichtian Baculites baculus zone from the Raton Basin (Sealey and Lucas 2022). For this study, we designated the geological formation as "unknown" for any specimens with uncertain locality information, including those reported from Maastrichtian horizons, which all had poorly documented or unverifiable provenance information (see Supplementary Text).…”

“…The Late Cretaceous Placenticeras of the eastern Gulf Coastal Plain represent a significant gap in our understanding of the taxonomy, paleobiogeography, and evolution of this genus and its potential utility for biostratigraphic zonation or correlations; they remain relatively understudied compared with Placenticeras faunas from coeval intervals elsewhere in North America (including Texas, the Western Interior, and the Atlantic Coastal Plain; e.g., Roemer 1852; Gabb 1872; Reeside 1927; Wolleben 1967; Cobban and Hook 1983; Kennedy 1988; Cobban et al 1989; Kennedy and Cobban 1991a, 1993a,b,c, 1994a,b, 1999; Kennedy et al 1995b, 1996, 1997b, 2001, 2004; Sealey and Lucas 1997, 2011, 2016, 2018, 2019, 2022; Tsujita and Westermann 1998, 2001; Landman et al 2006; Waggoner 2006; Cobban 2016) or Europe (e.g., Summesberger 1979; Błaszkiewicz 1980; Marcinowski 1980; Kennedy et al 1981, 1995a; Kennedy and Wright 1983; Kennedy 1984, 1986, 1987; Kennedy and Juignet 1984; Summesberger et al 1996, 2017a,b; Wilmsen and Nagm 2013, 2014).…”