One of the best indicators of how warm climate conditions became in the early Miocene can be seen in the presence of coconut palms in the New Zealand fossil record. A coconut palm (Cocos zeylandica), a small extinct species found only in New Zealand, is known from its fruits (or coconuts) and represents a unique miniature variety. The coconuts measure no more than 4cm in longest dimension and are about the size of a walnut. Although all specimens originally would have been ovoid in shape, they have become squashed to varying degrees through the pressures of the surrounding sediment. However, they are easily identifiable as coconuts in spite of their small and flattened shape, as they retain 3 round depressions at one end that correspond to the 3 'eyes' present in all modern coconuts.

Specimens of C. zeylandica are found on Cooper's Beach, Mangonui (Doubtless Bay), Northland, where they have been washed out of carbonaceous sandstone.