Scientists have found a real, not-live "sea monster" they say finally fills an evolutionary gap between sea and land dwellers around the time of the dinosaurs. Cartorhynchus lenticarpus—imagine a dolphin with huge flippers and a short snout—made waves in what is now China 248 million years ago, National Geographic reports. Most remarkable, however, is that researchers believe it's the first amphibious ichthyosaur, or "fish lizard," ever found. Scientists knew ichthyosaurs, which could grow to the length of a tractor-trailer, evolved from land to sea, but "an amphibious animal was somehow missing from the ichthyosaur record," says a researcher. Now, the animal captured in a 1.5-foot-long fossil in Anhui Province represents a "milestone."
LiveScience reports the creature is "a primitive type of ichthyopterygian, a group related to ichthyosaurs," but also that it's "the smallest known ichthyosaur-type creature." Researchers believe Cartorhynchus was fully grown at 1.3 feet long. Its large flippers were great for moving around on land, like a seal, while its short limbs and thick ribs made it a decent, bottom-dwelling swimmer. Its short snout, however, hadn't yet evolved into one long enough to catch fish, researchers say. Instead, it may have sucked up soft-bodied creatures like a vacuum. The fossil find also reveals ichthyosaurs took 4 million years to reappear in China after a mass extinction 252 million years ago, researchers say. (Fossils recently revealed a theory as to why whales got so big.)