Leaf fossils from Chubut, Patagonia, Argentina, suggest life rebounded surprisingly quickly in the wake of the extinction event known as the Cretaceous-Paleogene extinction event. Photo by Peter Wilf / Penn State

STATE COLLEGE, Pa., Nov. 7 (UPI) -- Patagonian leaf fossils suggest life rebounded surprisingly quickly in the wake of the mass extinction event that killed off the dinosaurs.

The evolution of insect life can be gleaned from ancient leaf fossils. Insect larvae burrow into leaves, leaving behind tiny tunnels that can be found millions of years later in fossilized plant material. Scientists call the tunnel-makers "leaf miners."


"Insects and plants are the most diverse multicellular organisms in the world, and they are known to respond to major environmental changes," Michael Donovan, a doctoral student in geosciences at Penn State University, said in a news release. "So they make a great resource to study our past."

In the geologic and fossil record, the 66-million-year-old mass extinction event is known as the Cretaceous-Paleogene boundary. Most of what scientists know about life during the first few million years after the K-Pg boundary is derived from fossils recovered in North America, near the site of the asteroid that struck Chicxulub, Mexico 66 million years ago.

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Research suggests plant and insect biodiversity in North America didn't return to its pre-K-Pg abundance for 9 million years after the extinction event. The new leaf fossils, however, show life recovered more quickly in Patagonia -- as soon as 4 million years after the disappearance of the dinosaurs.

Though no leaf miners survived extinction, new species closer to the impact zone were quicker to diversify and grow in abundance.

"The richness of plant-insect associations that we observed during the recovery may be a contributing factor to insect biodiversity in modern South America," Donovan said. "We can look far into the past and see these patterns that influence life on Earth as it is today."

Researchers described their new findings in the journal Nature: Ecology and Evolution.