Flat latitudinal diversity gradient caused by the Permian-Triassic mass extinction.

Area of Science:

• Paleontology
• Biodiversity Science
• Geological History

Background:

• The latitudinal diversity gradient (LDG) is a fundamental pattern in global biodiversity.
• Identifying drivers of the LDG is challenging due to covarying spatial factors.
• Deep-time geological records offer insights into historical biogeographic dynamics.

Purpose of the Study:

• To investigate changes in the LDG shape across the Permian-Triassic mass extinction event.
• To understand the deep-time mechanisms influencing biodiversity patterns.
• To analyze the impact of environmental extremes on marine fossil diversity.

Main Methods:

• Utilized a comprehensive marine fossil occurrence database (52,318 records).
• Analyzed changes in the latitudinal diversity gradient during the Permian-Triassic.
• Correlated gradient shifts with prevailing environmental conditions, including warming.

Main Results:

• The Permian-Triassic mass extinction caused a significant shift in the LDG.
• The gradient changed from a tropical diversity peak to a flattened distribution.
• A flattened LDG persisted throughout the Early Triassic (approx. 5 million years).

Conclusions:

• Environmental extremes, particularly global warming, drove selective extinctions in low latitudes.
• Diversity accumulated in high latitudes via origination and poleward migration.
• These combined factors explain the flattened LDG observed in the Early Triassic.