Ocean life
Ancient Colombian fossils reveal new evolutionary pattern
Researchers propose a 'Biotic Inflection' where old and new marine species coexisted in a diverse Early Cretaceous ecosystem.
Reported by ScienceDaily · · 1 min read
Fossils from central Colombia’s Paja Formation are shedding light on a unique period in evolutionary history. Scientists have found evidence of Jurassic-era animals nearing extinction living alongside emerging Cretaceous species, challenging the idea that major evolutionary shifts require mass extinctions.
The discovery, led by researchers from McGill University and Colombia’s Centro de Investigaciones Paleontológicas, introduces the concept of a 'Biotic Inflection'—a turning point where older and newer lineages coexist. This pattern was observed in the Early Cretaceous marine ecosystem near Villa de Leyva, preserved in remarkable detail.
A thriving ancient ocean
The Paja Formation’s rich fossil record includes giant marine reptiles such as long-necked plesiosaurs, crocodile relatives, turtles, sharks, and crustaceans. These creatures formed the Paja Biota, one of the most complex marine communities known, with a diverse food web featuring numerous apex predators.
Researchers suggest that warm temperatures, high sea levels, and nutrient-rich coastal waters created ideal conditions for this biodiversity. New ocean connections between the early Atlantic and Pacific may have further supported the coexistence of different animal groups.
The findings propose that some evolutionary transitions may occur through periods of high diversity rather than catastrophic events. However, the team notes that more fossil evidence and global comparisons are needed to confirm how widespread this pattern was.
The study could reshape how scientists understand changes in Earth’s biodiversity, offering a new model for evolutionary shifts without mass extinctions.
