Ancient Long-Necked Marine Reptile Discovered in Alaska

Researchers working along the side of a vertical cliff in Alaska’s Talkeetna Mountains have uncovered the 70-million-year-old fossils of a type of plesiosaur called an elasmosaur. These Late Cretaceous marine reptiles had extremely long necks, small heads, and paddle-like limbs for swimming. “Picture the mythical Loch Ness monster and you have a pretty good idea what it looked like,” Patrick Druckenmiller from the University of Alaska Museum says in a statement. This is the first time an elasmosaur has ever been unearthed in this state.

Its vertebra was discovered eroding out of the bluff by Anchorage-based fossil collector Curvin Metzler, who was actually looking for fossilized invertebrates. The bones were located about halfway up an 18-meter (60-foot) vertical cliff. Druckenmiller’s team visited the site in June. “We got a good chunk of the animal,” he says, “but there is still more to excavate.” They hope to recover the rest of the skeleton next summer. 

Based on the size of the bones they’ve successfully excavated, the animal was at least 7.6 meters (25 feet) long, and half of that was just neck. In a recent study, researchers counted the number of vertebrae in an elasmosaur discovered in the 1800s and previously dubbed “the longest-necked vertebrate.” It had 72 neck vertebrae, making it one of the longest-necked animals that ever lived (but not the longest). 

Two other types of ancient marine reptiles have previously been discovered in the rocky hillsides of Alaska: dolphin-shaped ichthyosaurs and “ocean lizards” called thalattosaurs. The sediment in which this new skeleton was found was “laid down on the seabed about 70 to 75 million years ago,” Druckenmiller tells Live Science. “At that time there was a sea along the southern margin of [what is now] Alaska.” Millions of years of tectonic activity under that ancient sea caused the seafloor to rise.

Metzler (left) and Druckenmiller examine the spot where bones were found sticking out of the cliff in the Talkeetna Mountains. Pat Druckenmiller.