Researchers have “re-discovered” the fossil of a marine reptile that they now believe it the largest of its kind on record, a sea dragon that swam the seas 200 million years ago in the age of dinosaurs. It’s the largest Ichthyosaurus specimen ever discovered at more than three meters, and while it was discovered two decades ago on the coast of England, it had gone unnoticed until a paleontologist spotted it on display.

It goes to show that many specimens like this can be “rediscovered” in museum collections and a scientist doesn’t even to have to go out into the field to make a new discovery, the paleontologist from the University of Manchester, Steven Sachs, said according to a BBC report. The specimen is a Ichthyosaurus somersetensis, and it was likely an adult female who was pregnant when she died.

It’s the only Ichthyosaurus specimen with an embryo, making it a special find for scientists. These “sea dragons” lived during the Triassic period, peaked in the Jurassic, and then died out in the Cretaceous a few million years before the last last dinosaurs were wiped out.

“Scientists from the UK and Germany have discovered the largest Ichthyosaurus on record and found it was pregnant at the time of death,” the statement from the University of Manchester reads. “The new specimen is estimated to be between 3 and 3.5 m long and is an adult female. Ichthyosaurs were a highly successful group of sea-going reptiles that became extinct about 90 million years ago. Often misidentified as swimming dinosaurs, these reptiles appeared before the first dinosaurs had evolved. The largest species of ichthyosaur grew to over 20 m in length.”