A 246-million-year-old fossil discovered in Canterbury has upended long-standing theories about how early sea-going reptiles dispersed around the globe - and our understanding of the earth's history.
The nothosaur vertebra was discovered in 1978 at Balmacaan Stream and has since been held at GNS Science.
However it wasn't until this year that an international team of scientists analysed the vertebra and other associated fossils.
The Canterbury fossil was discovered by Doug and Hamish Campbell. Dr Hamish Campbell speaks to Mark.