When did kiwi and tuatara arrive in New Zealand and how did they get here? These are the kinds of questions being answered by some amazing fossil discoveries that have been made in Otago in the last few years.
I’ve been part of a team of researchers visiting fossil sites around St Bathans since 2001. When our team set out to re-examine sites where ancient (c.20 million year old) duck bones had been found, we had no idea that this was just the beginning of a project that has seen us dig through 100s of tonnes of old lake bed looking for tiny fossils.
Since our first visit to the area we have been amazed by how many bones we have found and have now built up an impressive list of animal species based on these fossils: 15 fish, 2 NZ frogs, 1 tuatara-relative, 2 skinks, 2 geckos, 1 turtle, 1 crocodilian, 2 moa, 1 kiwi, 8 geese and ducks, 1 petrel, 2 birds of prey, 1 adzebill, 2 rails, 1 gull, 2 wading birds, 2 herons, a flamingo-like palaelodid, 2 pigeons, 4 parrots, 1 swiftlet, 1 owlet-nightjar, 7 song birds and 5 bats. The fauna includes representatives of all the quintessential endemic New Zealand terrestrial vertebrate groups such as our native frogs, tuatara, moa, kiwi, and acanthisittid wrens. A dozen kinds of molluscs, such as the freshwater limpet Latia, are also present in the deposits.
But the fossil collection provides us with a lot more than just a list of species. For example, the kiwi fossils are from birds much smaller than kiwi living today, suggesting that kiwi ancestors may still have been able to fly 20 million years ago. The origin of kiwi has been in debate for years – some suggested that they were flightless since our continent – Zealandia – split from the rest of Gondwana between 82 and 55 million years ago but other researchers suggested that their ancestors flew here. Now we have some evidence that ancestral kiwi may still have been able to fly long after the continents broke apart.
A different story has emerged for tuatara. Some St Bathans fossils are inseparable from modern tuatara bones, indicating a long history for tuatara in Zealandia. This would match most theories that the ancestors of tuatara have been on Zealandia since it split from Gondwana and that these unique reptiles have been isolated here ever since.
The St Bathans digs have involved many generous people (landowners; colleagues; support agencies – particularly Canterbury Museum, the University of New South Wales and Flinders University; funding bodies – particularly the Australian Research Council) and revealed a startling array of fossils. We intend to continue this work in order to find out more about the origins of New Zealand’s animals. The one thing that is certain in palaeontology is that you never know what you are going to uncover next – and that’s the fun of it.
This research at St Bathans uncovered the fossilised parrot bone and freshwater limpet shell on display in the exhibition DeCLASSIFIED!
DeCLASSIFIED! Nature’s secrets exposed at Te Papa – find out more
You can help Te Papa make more discoveries. For the DeCLASSIFIED! exhibition, we’re particularly interested in the spiders and ferns you can find. You’ll help us with out science, we’ll help you with the name of what you’ve seen, and the photo of your observation might end up as part of the exhibition!
Help us make more discoveries