Prehistoric Fossil Shows Ichthyosaur May Have Been Pregnant With Octuplets

This marine reptile was a fierce ocean predator.

It’s hard to be a mom who has it all. Take the ichthyosaur: This ancient, predatory reptile spent its days dominating the oceans, cruising the seas at a mean speed of 22 miles per hour. But, as it goes in the animal kingdom, at times the fearsome “fish-lizard” was a mother too — evidenced recently by the discovery of a 180 million-year-old pregnant ichthyosaur’s skeleton.

Peaking through its ribs, paleontologists announced Thursday in the Proceedings of the Yorkshire Geological Society, are the remains of between six and eight tiny embryos. This spectacular find adds to the growing number of ichthyosaur specimens found in the rock beds of the United Kingdom, and the sixth ichthyosaur specimen sourced from Britain found with embryos. All were collected from Jurassic exposures dated between 200 to 190 million years old, while this specimen is the first to be found specifically in Yorkshire.

“We also considered the possibility that the tiny remains could be stomach contents, although it seemed highly unlikely that an ichthyosaur would swallow six to eight aborted embryos or newborn ichthyosaurs at one time,” co-author and University of Manchester paleontologist Mike Boyd, Ph.D. explained in a statement released Thursday. “And this does not seem to have been the case, because the embryos display no erosion from stomach acids. Moreover, the embryos are not associated with any stomach contents commonly seen in Early Jurassic ichthyosaurs, such as the remains of squid-like belemnites.”

Artist rendition of the pregnant ichthyosaur.

Nobumichi Tamura

This specimen is enclosed within a small boulder, that’s been cut in half and polished. Discovered in 2010 near Whitby, North Yorkshire, the fossil had been in possession of fossil collector Martin Rigby until it was by the Yorkshire Museum, York. Examination of the fossil by Boyd and paleontologist Dean Lomax, Ph.D., confirmed Rigby’s suspicion that this Octomom was pregnant at the time of her death. Curious spectators can see the fossil in person at the Yorkshire Museum’s current Jurassic World exhibit.

While dinosaurs roamed on land, ichthyosaurs were the master predator of the ocean during the Jurassic era. Sometimes known as “sea dragons,” they were eventually replaced by plesiosaurs — massive, long-necked marine reptiles that first appeared in the latest Triassic Period. But during their hey-day, they were the top of the food chain: Swimming undulating like modern-day eels, although they evolved from an unidentified land reptile that moved back into the water. They died out approximately 25 million years ago before the Cretaceous-era mass extinction that took out most of life on Earth.