Scientists have discovered the remains of a mysterious, car-sized shark, which swam the coastlines of the Atlantic and Pacific oceans around 20 million years ago. The newly discovered species is a relative of the super-predator megalodon (pictured above), and an ancient ancestor of today’s great white sharks – but there’s a 45-million-year gap in the fossil record before this new species appeared, leaving a lot of unanswered questions about how the shark evolved, and how long it survived. 
“The fact that such a large … shark with such a wide geographic distribution had evaded recognition until now indicates just how little we still know about the Earth’s ancient marine ecosystem,” lead researcher Kenshu Shimada from DePaul University in Chicago told Laura Geggel from Live Science.
The new species has been named Megalolamna paradoxodon – putting it in a brand new genus of its own. The species name paradoxodon refers to the fact that the shark emerged so suddenly in the geological record, after appearing to have split from its closest relative, Otodus, around 45 million years earlier.
So far, only five of the species’ 5-cm-long (2-inch) teeth have been found in California, North Carolina, Japan, and Peru – covering most coastlines of the Pacific and Atlantic oceans.
Based on these remains, the researchers estimate that the shark grew to around 3.7 metres (12 feet) long, making it significantly smaller than its relative, megalodon, which is thought to have reached a humungous 18 metres (59 feet) in length, and lived from 23 to 2.6 million years ago. 
But Megalolamna paradoxodon was still large enough to have feasted on medium-sized fish, and would have been just slightly smaller than today’s great white sharks, according to the researchers.
By: sciencealert.com
