Exotic Paradise

A catalogue of wildlife basked in a tropical climate.

Early New Zealand echoed to the sound of birds, secure from the furry predators of other continents, until the relatively recent arrival of predatory mammals over the past 800 years. Right? Wrong. Our mammal-free prehistory was blown out of the water in 2006, when researchers in Central Otago found the fossil of a small mouse-like creature that appeared to have pattered across our forest floor 16-19 million years ago. Different from placental or marsupial mammals, and completely unrelated to mice, it belonged to a primitive group living during the Mesozoic period before the Zealandia landmass split away from the Gondwana supercontinent. Since then, the discovery of an unrelated molar suggests a second small land mammal was part of a diverse catalogue of early New Zealand wildlife that we now know included turtles, crocodiles, giant bats and flamingos.

Over the past 17 years, an international team led by New Zealand palaeontologist Trevor Worthy, based at Flinders University in Adelaide, has been working on a 40m-thick sequence of sediment layers from the massive palaeolake, Manuherikia, that covered 5600sq km of Central Otago about 20 million years ago. Nine times the size of Lake Taup, the lake bed has proved to be an extensive boneyard for our historic flora and fauna, overturning the notion that we were a land of birds, bats and insects. Now it appears our archetypal species – our tuatara, moa, kiwi, wrens and native frogs – evolved in a far more complex environment.