2025/12/09 by Kenshu Shimada, Patrick B. Gonzales, Michael J. Everhart +3
Earth and Planetary Sciences · Environmental Science · #Paleontology and Evolutionary Biology #Ichthyology and Marine Biology #Geological formations and processes
paper · doi:10.1660/062.128.0302
The Lincoln Limestone Member of the Greenhorn Limestone is an Upper Cretaceous sedimentary rock unit formed in the North American Western Interior Seaway during the Cenomanian Stage. Here we report a new Lincoln Limestone fossil vertebrate assemblage from the Comanche National Grassland in southeastern Colorado, USA. The fossil assemblage consists of at least 22 taxa, comprising minimally 11 chondrichthyans, 10 osteichthyans, and one squamate reptile. The new fossil assemblage is compared with other chronologically similar (i.e. putatively late middle-early late Cenomanian) vertebrate assemblages in Colorado, Kansas, and Nebraska, with a revised comparative taxonomic list of those assemblages. Examining stratigraphically well-constrained fossil assemblages shows differing environments and habitat preferences across the Western Interior Seaway. Deeper water localities (Colorado) versus localities nearer to the eastern shoreline (Nebraska) exhibit variation in lithologic and taxonomic compositions due to sea level change through time and space.