Summary (tl;dr)

A recent discovery of 115-million-year-old "mega-shark" vertebrae in Australia is rewriting the timeline of shark evolution, indicating that these colossal predators emerged much earlier than previously understood.

Essential Background

Prior to this discovery, scientists generally believed that modern shark lineages, specifically the lamniforms which include great white and mako sharks, began to evolve into gigantic sizes later in their evolutionary history. Early lamniforms, appearing around 135 million years ago, were thought to be relatively small, typically around 1 meter in length. The extinct family Cardabiodontidae, known for its huge predatory sharks, was previously understood to have dominated the oceans approximately 100 million years ago.

The Full Story

Researchers recently uncovered five 115-million-year-old vertebrae from a colossal ancient lamniform shark on a beach near Darwin, Australia. This prehistoric predator, an early relative of today's great white and mako sharks, is estimated to have measured between 6 and 8 meters long and weighed over 3 tonnes. The significance of this find lies in the fact that it predates all previously known Cardabiodontids by approximately 15 million years. This suggests that sharks experimented with and achieved enormous body sizes far earlier in their evolutionary development than scientists had previously imagined. The groundbreaking findings of this study, which was coordinated by the Swedish Museum of Natural History, have been published in the scientific journal Communications Biology.

Why It Matters

This discovery profoundly impacts our understanding of shark evolution by pushing back the timeline for the emergence of gigantic predatory sharks. It indicates that early modern shark lineages were already attaining colossal sizes much earlier, likely competing with the large marine reptiles of the Age of Dinosaurs for the position of apex predator in ancient oceans. The find offers crucial new insights into the dynamics of prehistoric marine ecosystems and the complex evolutionary pressures that shaped the development of mega-predators.

Geographic Location

• Near Darwin, Northern Territory, Australia (discovery of 115-million-year-old mega-shark vertebrae)
• Swedish Museum of Natural History, Stockholm, Stockholm County, Sweden (coordination of the study)
• Virtual/Online (publication in Communications Biology journal)