Bones that recently emerged from the dirt in northwest India belonged to a “sea monster” the size of a small boat prowled the deep, dark waters more than 150 million years ago.
The newfound fossil is a nearly intact skeleton of an ichthyosaur, a group of marine reptiles that terrorized the seas during the age of the dinosaurs. These animals were the dolphins or whales of their time: svelte fish-eaters with huge eyes, narrow jaws, and cone-shaped teeth.
The Indian ichthyosaur, which lived between 152 and 157 million years ago, is the first Jurassic sea monster discovered in the region. Unveiled on October 25 in PLOS ONE, the fossil is now helping paleontologists better understand how ichthyosaurs spread across the ancient world.
“This is a fantastic discovery, and is by far the best ichthyosaur skeleton ever found in India,” says Steve Brusatte, a paleontologist at the University of Edinburgh who wasn’t involved with the study.
“Ichthyosaur fossils are well known from the northern continents but are very rare down south,” Brusatte adds. Globally, more fossils from this group have so far been found in North America and Europe. (See a sea monster that was found near a Scottish loch in 2016.)
“So this new skeleton has the potential to reveal many secrets about ichthyosaur evolution and biogeography.”
Indian paleontologists came across the lucky find south of the village of Lodai, in India’s Gujarat province, in 2016.
The ichthyosaur was embedded in extremely hard sedimentary rock, and its excavation was grueling work: Today, the region’s climate is arid and harsh, with temperatures hitting more than 95 degrees Fahrenheit.
After 1,500 man-hours of digging, the team unearthed the stunningly preserved skeleton. The ichthyosaur’s backbone was still in more or less a continuous line, and its left forefin kept the shape it had in life. (Find out about a baby sea monster fossil that was found preserved inside its mother.)
Guntupalli V.R. Prasad, a paleontologist with India’s University of Delhi who studies dinosaur-era vertebrates, says that the find came as a surprise. “I did not do much research on the vertebrate fossils of this region earlier, as it was considered to yield very few vertebrate fossils,” he says.
Prasad quickly realized the magnitude of the find. Not only is the fossil the most complete Indian ichthyosaur ever found, it’s also the first from the Jurassic period recovered in the country. All previous finds are about 50 million years younger and consist only of isolated teeth or poorly preserved vertebrae, Prasad says.
When the ichthyosaur lived, this region of India was covered by a tropical sea, which the 16-foot-long reptile prowled for its meals. Its cracked, worn teeth imply that it was eating tough prey such as armored fish and ammonites, spiral-shelled mollusks that resembled today’s nautiluses.
The team also found that the Indian ichthyosaur is closely related to group members found farther north—evidence of sea monster globalization.
Together with invertebrate fossil evidence, the ichthyosaur find suggests that a massive seaway once crossed the ancient continent of Gondwanaland, cutting through land that is now split across western India, Madagascar, and South America.
If so, it could shape paleontologists’ understanding of how marine life spread through Jurassic oceans.
“This find helps to show how globally widespread ichthyosaurs were during the time of dinosaurs,” says Brusatte. “They seem to have lived everywhere in the oceans, all over the world, at the same time dinosaurs were thundering across the land.”