A Ninja Turtle from Deep Time
In the Pleistocene epoch, the area of what is now Queensland was where a truly strange creature: a terrestrial turtle with a horned skull and a clubbed tail. This was Ninjemys oweni, a member of the extinct Meiolaniidae family. Its shell, or carapace, measured about one meter (3.3 feet) in length, and the entire animal is estimated to have weighed around 200 kilograms (440 pounds). It was a heavily-built herbivore, likely grazing on vegetation in the wooded savannas and open forests of the period.
The most striking feature of Ninjemys was its skull. Unlike living turtles, it possessed large, bony horns. The most prominent pair projected directly out to the sides, giving the skull a total width of nearly 70 cm (28 inches). These horns, along with smaller ones, meant the turtle could not retract its head into its shell for protection. To compensate, it had other defenses. Its body was encased in thick armor, and its tail ended in a bony club, reminiscent of an ankylosaur dinosaur.
Fossils of Ninjemys oweni are primarily found in Pleistocene deposits in southeastern Queensland, particularly in the Darling Downs region. This animal was one of the last of its kind, a relict of an ancient Gondwanan lineage of stem-turtles that had existed for millions of years. It survived in Australia until about 46,000 years ago, its disappearance coinciding with the arrival of the first humans on the continent.
A Case of Mistaken Identity
The discovery of Ninjemys oweni has a history of confusion. The first skull was found in 1879 at King's Creek in Queensland by a local collector named G. F. Bennett. Bennett correctly identified it as a turtle and sent it to the famous British anatomist Sir Richard Owen. Owen, however, disregarded Bennett's assessment and mistakenly identified the skull as belonging to a giant monitor lizard he had named Megalania. It wasn't until 1888 that Arthur Smith Woodward correctly identified the fossil as a distinct turtle species, naming it Meiolania oweni in Owen's honor.
Decades later, in 1992, American paleontologist Eugene S. Gaffney determined that the Queensland turtle was different enough from other Meiolania species to warrant its own genus. He renamed it Ninjemys. The name is a direct and playful reference to the Teenage Mutant Ninja Turtles, combining "Ninja" with "emys," the Greek word for turtle. Gaffney's official etymology for the name was "in allusion to that totally rad, fearsome foursome epitomizing shelled success".