The island of the horned turtles
On the remote Lord Howe Island, paleontologists have uncovered extensive remains of Meiolania platyceps, a large, herbivorous terrestrial turtle. This animal possessed a bizarrely armored skull with two prominent horns projecting sideways and backwards. Hundreds of fossil specimens, including five complete skulls, have been found on the island, making it the best-known species of its kind. Meiolania could not retract its head into its shell, a defensive limitation that may explain its elaborate headgear and heavily armored body.
The creature's defenses did not stop at its head. Its tail was encased in bony rings and ended in a formidable, spiked club. This anatomical feature is an example of convergent evolution and resembles the tails of unrelated armored animals like ankylosaur dinosaurs and glyptodonts. The total length of an adult Meiolania platyceps could reach up to 2.5 meters. It belongs to the Meiolaniidae, an extinct family of stem-turtles that represent a separate lineage from any modern turtle or tortoise.
A megafaunal survivor
While megafauna on mainland Australia, including other species of Meiolania, largely disappeared by about 46,000 years ago, island populations held on for millennia. The species on Lord Howe Island, M. platyceps, is known from Pleistocene-era deposits, some as old as 120,000 years. Its final extinction date on the island is not precisely known but occurred before the arrival of Europeans in 1788.
Related meiolaniid turtles survived even longer on other Pacific islands. On Vanuatu, fossils of a related species were found in a Lapita cultural settlement, dated to around 2,800 years ago. The bones were discovered in midden and cemetery layers, consisting mainly of leg bones, which suggests the turtles were butchered and eaten by the first human inhabitants. The extinction of these remarkable island giants appears to coincide closely with human arrival throughout the Southwest Pacific.