Authors: Catherine Badgley, John Barry, Anna K. Behrensmeyer, Thure Cerling, Lawrence J. Flynn, Michèle E. Morgan, David Pilbeam
Published: 2025-05-30
DOI: 10.1146/annurev-earth-080723-082338
Source: Full article
The continental fossil record has exceptional, long sequences of fossiliferous strata that are the basis for evaluating ecosystem dynamics and their formative influences. The Siwalik sequence of South Asia is one example. It occurs in the Potwar Plateau (Punjab Province, Pakistan) and spans 18–1 Ma. The sequence consists of alluvial sediments deposited in a foreland basin created by the collision of the Indian and Eurasian tectonic plates. Sediments representing large and small river channels and their associated floodplain deposits correspond to mountain-sourced large rivers and foothill-sourced smaller rivers. Vegetation attributes are recorded in stable carbon isotopes and biomarkers in paleosols. Molluscs, fishes, crocodilians, turtles, lizards, snakes, birds, and mammals are preserved throughout the sequence. Mammalian faunas had exceptionally high species richness (116 species) at their peak and included up to 18 species of co-occurring megaherbivores (>800 kg). Significant changes over time in species richness, taxonomic composition, and ecological structure of mammalian faunas coincided with major changes in climate and vegetation.