Now that paleontologists have assembled a complete humerus bone from the sea turtle Atlantochelys mortoni, they have more information about the species and its overall size. Prior to the discovery of the bone's missing half, the partial limb in the collections of the Academy of Natural Sciences of Drexel University was the only known fossil specimen of its genus and species. Based on the complete limb, they calculated the animal's overall size to be about 10 feet from tip to tail, making it one of the largest sea turtles ever known. It may have resembled modern loggerhead turtles. In this illustration, it is depicted with the outline of a human diver to indicate scale. The turtle lived 70 to 75 million years ago.