Related Experiment Video
Updated: Jan 17, 2026

Measuring and Mapping Patterns of Soil Erosion and Deposition Related to Soil Carbonate Concentrations Under Agricultural Management
Published on: September 12, 2017
Squamate fauna from the Denver Basin shows major ecosystem disruption across K/Pg boundary
Holger Petermann1, Tyler R Lyson1
1Department of Earth Sciences, Denver Museum of Nature & Science, Denver, CO 80205, USA.
Abstract:
The Cretaceous/Palaeogene (K/Pg) boundary marks the most recent and the second-most severe mass extinction in Earth's history. Marine K/Pg boundary sections that preserve uninterrupted sedimentation are abundant, and thus the global marine response to this extinction event is well understood. Similar terrestrial sedimentary sequences that record the before and after of the extinction and that are also geochronologically well constrained are rare. We describe and compare the non-marine squamate diversity immediately before (ca 57 kyr) and after (ca 128 kyr) the K/Pg mass extinction from two geographically and chronostratigraphically well constrained localities in the Denver Basin, Colorado. The latest Cretaceous squamate record there consists of 235 isolated fossils and is extraordinarily diverse, with 27 operational taxonomic units, whereas the earliest Palaeocene record is depauperate in both richness (3 taxa) and abundance (20 isolated fossils)-a ca 91% drop in specimen abundance and a 93% extinction rate. Integrating the Denver Basin squamate fossil record with that of the Williston and Powder River basins of Montana, North and South Dakota, and Wyoming, provides a regional extinction rate of between 75 and 84% for squamates in the Western Interior of North America and suggests this group was more severely impacted across the K/Pg boundary than other small-bodied vertebrates.
More Related Videos
Related Concept Videos
The Fossil Record
Habitat Fragmentation
What is Evolutionary History?
Keystone Species
Conservation of Declining Populations
Diversity of Protists III

