Scientists estimate that this shark was about eight meters long, challenging the assumption that the first modern sharks were small.
A gigantic shark patrolled Earth’s oceans tens of millions of years before of the appearance of the famous megalodon, according to new research in Communications Biology.
Fossils discovered near Darwin in northern Australia have been identified as belonging to the oldest megapredator shark known within the modern lineage of sharks.
The shark lived about 115 million years agoduring the Cretaceous period, a time when the seas were populated by formidable marine reptiles such as plesiosaurs and ichthyosaurs. Until then, scientists believed that the earliest members of the modern group of sharks, known as lamniforms, were relatively small when they first appeared in the fossil record around 135 million years ago. Recently analyzed remains challenge this assumption, suggesting that some lamniform sharks reached lengths of up to eight meters much sooner than previously thought.
The evidence comes from five fossilized vertebraeeach approximately 12 centimeters wide. Although the fossils were unearthed in the late 20th century, they remained forgotten in museum collections for decades before being re-examined with modern analytical techniques. Its size alone indicates an animal of extraordinary proportions.
Shark fossils usually consist of teeth, since sharks have cartilage skeletons instead of bonewhich rarely fossilizes. While teeth can reveal diet and eating behavior, vertebrae provide crucial clues about body size. In this case, the vertebrae confirmed that the ancestral shark was among the largest predators of its time, says .
The researchers claim that the shark closely resembled today’s large predator species, both in form and function. His body plan was similar to modern sharks and probably occupied the role of top predator in its ecosystem. This suggests that the aerodynamic design and hunting efficiency observed in today’s sharks evolved very early and proved so successful that it has changed little over time.
One of the most significant implications of the study is how quickly sharks appear to have risen to the top of marine food chains. Rather than gradually evolving into top predators, lamniform sharks appear to have reached this status quicklyquickly adapting to climate and ecosystem changes during the Cretaceous.
Scientists say this evolutionary resilience may contain lessons for today. Understanding how ancient sharks responded to drastic environmental changes can help researchers predict how modern ocean predators might cope with today’s rapidly changing climate and marine conditions.
