Megalodon's Gigantism Still Unmatches With Other Sharks

Megalodon’s gigantism even among its extinct relatives, was unequaled in length and mass. Megalodon was the most massive shark that ever lived, and its gargantuan girth was highly unusual even among sharks, scientists recently discovered. 

Megalodon's Gigantism Still Unmatches With Other Sharks

In fact, Megalodon’s gigantism — it’s estimated to have measured up to 50 feet (15 meters) in length, about as long as a bowling lane — was “off-the-scale,” researchers wrote in a new study.

Evidence from extinct and living sharks in the order Lamniformes, the group that includes Megalodon, revealed that not only was the king of sharks an extreme outlier when compared with modern species; it was also substantially bigger than the next-biggest extinct shark in the Lamniformes order by at least 23 feet (7 m), the scientists reported.

Modern sharks are certainly pipsqueaks when compared with Megalodon (Otodus megalodon). The biggest known predatory species, the great white shark (Carcharodon carcharias), grows to only about 20 feet (6 m) long, and the filter-feeding whale shark (Rhincodon typus), the biggest fish species alive today, measures about 18 to 33 feet (6 to 10 m) from nose to tail tip, on average. 

There are 13 species of lamniform sharks alive today; these include mako sharks (the Isurus genus), deep-sea goblin sharks (Mitsukurina), and thresher sharks (Alopias), as well as great whites. 

Most Megalodon fossils date to around 15 million years ago, and lamniform were plentiful from the end of the Mesozoic era (252 million to about 66 million years ago) into the early Cenozoic era, (65 million years ago to the present). However, little is known about the anatomy of extinct lamniforms; since shark skeletons are made of cartilage rather than bone, they are extremely scarce in the fossil record, save for their plentiful fossilized teeth, said lead study author Kenshu Shimada, a professor of paleobiology at DePaul University in Chicago and a research associate at the Sternberg Museum in Kansas. 

Tooth size can be used to estimate a shark’s body size because as sharks grow they continuously replace their teeth, getting new and bigger ones over time. In the new study, Shimada and his colleagues generated a new tool for calculating body length: an equation representing the actual quantitative relationship between body length and tooth size in lamniforms. They based it on the teeth and known body lengths from 32 specimens of living, predatory lamniform sharks, representing all 13 species that are not plankton-eaters, Shimada told Live Science in an email. They then applied their equation to extinct predatory lamniforms.

Originally published at science