Data from: Flat latitudinal diversity gradient caused by the Permo-Triassic mass extinction

The latitudinal diversity gradient (LDG) is recognized as one of the most
pervasive, global patterns of present-day biodiversity. However, the
controlling mechanisms have proved difficult to identify because many
potential drivers covary in space. The geological record presents a unique
opportunity for understanding the mechanisms which drive the LDG by
providing a direct window to deep time biogeographic dynamics. Here we
used a comprehensive database containing 52,318 occurrences of marine
fossils to show that the shape of LDG changed greatly during the
Permian-Triassic mass extinction from showing a significant tropical peak
to a flattened LDG. The flat LDG lasted for the entire Early Triassic (~5
million years) before reverting to a modern-like shape in the Middle
Triassic. The environmental extremes that prevailed globally, especially
the dramatic warming, likely induced selective extinction in low latitudes
and accumulation of diversity in high latitudes through origination and
poleward migration, which combined together account for the flat LDG of
the Early Triassic.