Not So Drowned Continent
Fossils of an 18 million year old ancestor to the tuatara have been found outside of Saint Bathans, Otago, filling a huge void in the fossil record, and casting doubt on a widely held theory that New Zealand was once completely submerged. Geologists think Zealandia, the large submerged continent that New Zealand is a part of, broke away from the ancient southern supercontinent Gondwana 80 million years ago, drifted across the Tasman Sea. For many years there has been fierce debate over whether or not New Zealand went under with the rest of Zealandia during the migration, and the origin of New Zealand’s biota hinges on the answer. The new fossils support critics of the notion of submersion, substantially narrowing the window when animals and plants could have drifted over from Gowanda after New Zealand resurfaced. The tuatara is indigenous to New Zealand and is the only living member of the Sphenodontia family, dating back 200 million years. The fossil find also fills a 70 million year gap in the Sphenodontia fossil record.