Colombia fossil discovery reveals evolutionary Biotic Inflection

Researchers studying fossils in Colombia's Paja Formation have uncovered evidence of a unique evolutionary period where ancient animal groups nearing extinction coexisted with emerging lineages. This discovery suggests that major biological transitions can occur without the widespread destruction typically associated with mass extinctions.

Scientists from McGill University and the Centro de Investigaciones Paleontológicas (CIP) identified this pattern in an ancient marine ecosystem. The findings show a mixture of surviving Jurassic lineages and expanding Cretaceous groups. To describe this phenomenon, McGill biology professor Hans Larsson and PhD graduate Dirley Cortés have proposed the concept of a “Biotic Inflection,” representing a turning point where old and new groups thrive simultaneously.

The coexistence was likely driven by a combination of environmental factors, including warm greenhouse temperatures, high sea levels, and nutrient-rich coastal waters. Additionally, the emergence of new ocean connections between the eastern Pacific and the early Atlantic through present-day Colombia provided further opportunities for marine biodiversity to flourish.