Tuatara are unique in that they are the last surviving member of the Sphenodontids whose fossils have been found around the world dating all the way back to the dawn of the dinosaurs.

For the early part of their evolutionary history Sphenodontids were more numerous than their cousins the lizards and snakes. However from the Cretaceous period onwards they became increasingly rare in the fossil record, often only fragmentary jaws and teeth.

This paucity of fossils has meant that the origins of New Zealand’s unique tuatara are shrouded in mystery.

The discovery of the nearly complete Sphenodontid fossil from North America is a WOW moment in palaeontology, the stuff cover images are made of.

Using some amazing analytical methods, the scientists at Harvard University have shown that Navajosphenodon sani is the oldest member of the lineage that led to tuatara.

By comparing the new fossil to tuatara they have shown that the body form of tuatara has been conserved for at least 190 million years…a great example of if it ain’t broke, don’t fix it. This is remarkable and fits with what scientists know of slow rates of genome evolution in tuatara.

There is still a lot to discover about the evolution of tuatara but this is a first step. New fossil discoveries will shed further light on this remarkable animal, whether they are collected in the field or have been hiding in museum collections for 30 years like Navajosphenodon sani.