LIFE × EVOLUTION

Before the Dinosaurs

~270 to 252 million years ago

Phanerozoic · Paleozoic · Permian

For twenty million years the large land animals were relatives of mammals: tusked dicynodont herbivores moving in herds, and gorgonopsians with sabre teeth hunting them. Whole basins in South Africa and Zambia are made of their bones. Nearly every major group of them appears within about ten million years, after a long stretch in which the lineage leaves no fossils at all.

Why it matters

This is the world the end-Permian extinction erased. Mammals then spent 150 million years small and nocturnal, and it is easy to read that as their natural condition. It was not. The ecosystem they lost had been theirs, and a gorgonopsian found in Mallorca, older than any African one, suggests the group began in the tropics and that the famous South African record is a late chapter rather than the opening.

Dating & uncertainty

Nearly every major therapsid group appears within about ten million years in the middle Permian, after a long lineage with no fossils at all. A gorgonopsian from Mallorca, older than any African specimen, suggests the group started in the tropics and moved out, which would make the Karoo record a late chapter rather than the origin.

Sources

1. Kammerer et al. (2022), Journal of African Earth Sciences · The earliest gorgonopsians from the Karoo Basin of South Africa
2. Matamales-Andreu et al. (2024), Nature Communications · Early-middle Permian Mediterranean gorgonopsian suggests an equatorial origin of therapsids
3. Peecook et al. (2025), Journal of Vertebrate Paleontology · Successive assemblages of upper Permian vertebrates in the upper Madumabisa Mudstone Formation of the Luangwa Basin, Zambia

Earth history as one day

22:34:211 h 26 min before midnight

if Earth’s 4.54 billion years were compressed into a single day