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Iguanodon: The tooth behind Te Papa's dinosaur exhibit

An artist’s impression of an iguanodon. Image/Getty Images

The holy grail of dinosaur fossils is part of Te Papa’s new $12 million Te Taiao/Nature exhibition, thanks to an early family connection with New Zealand.

A small, brown molar, Te Papa exhibit GH004839, has a significance far exceeding its $1 million insurance value. The matchbox-sized tooth, from a herbivorous dinosaur that roamed various parts of the world about 140 million years ago, has been described as palaeontology’s answer to the Mona Lisa, the scientific equivalent of Archimedes’ bath and the holy grail of dinosaur fossils.

One of more than 1200 objects to be showcased in Te Papa’s new $12 million Te Taiao/Nature exhibition, the iguanodon tooth was the first identified evidence of what came to be recognised as dinosaurs and apparent proof of the scandalously irreligious concept of extinction.

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“Other fossils were found on the same site,” says New Zealand geologist Hamish Campbell, “but this was the beginning of the quest, so, in that sense, it is very significant.”

The fossil was found in 1822 near Cuckfield, Sussex, but since then, the story of its discovery has become clouded. A plaque on the house of country surgeon and fossil collector Dr Gideon Mantell in Lewes, near Brighton, says he discovered the tooth “in the Sussex Weald”.

However, later reports suggest it was not Mantell, as he originally claimed, but his wife, Mary Ann, who first spotted the tooth, in a pile of stones on the roadside while her husband was visiting a patient.

The fossil that led to the discovery of the iguanodon. Photo/Supplied

Certainly, it was Gideon who sent the fossil to respected French naturalist and zoologist Georges Cuvier. Although he initially dismissed it as a rhinoceros tooth, Cuvier changed his mind overnight, says Campbell, and concluded the remains were reptilian and possibly from a giant herbivore.

Mantell named it iguanodon (“iguana-tooth”) after the iguanas of the Caribbean, and the following year published a report on his discovery. In 1825, he was elected a fellow of the Royal Society.

Mary Ann Mantell, also a keen fossil hunter, accompanied her husband on his trips and illustrated his first book, The Fossils of the South Downs. But in 1839, after 23 years of marriage, she left him; that same year their son, Walter, sailed for New Zealand. Thirteen years later, Gideon Mantell died from an opium overdose.

Mary Ann Mantell and Dr Gideon Mantell. Images/Alamy

After his father’s death, Walter, a public servant and naturalist, inherited much of his collection, which was transported to New Zealand. Today, Walter Mantell is recognised as a natural history pioneer, with two native birds named after him. He donated money for the new Colonial Museum, the precursor to Te Papa, and in 1865, while also the MP for Wallace, oversaw its official opening in the absence of founding director James Hector. On display for the first visitors was the iguanodon tooth.

Since then, research has shown the plant-eating dinosaur to be very different from the bulbous-bodied creature in John Martin’s 1837 painting, The Country of the Iguanodon. Originally thought to have walked on all fours, the iguanodon is now known to have got about mainly on two legs. And what was thought to have been a nose horn is now known to be a spike on its thumbs.

NZ geologist Hamish Campbell. Photo/Margaret Low/GNS Science

“More and more material has been found,” says Campbell, “and through comparative anatomy, we can create remarkable reconstructions that we can actually feel very comfortable with.”

Such small fragments of fossilised life also give insight into their environment.

“You can think about bones and teeth as archives of the environment that we exist in. From an isotopic perspective, the air we breathe, the water we take in, the food we eat and our skeletal structures will take on the chemistry that relates to the time we are living in. There is no stasis.”

Te Taiao/Nature is open at Te Papa now.

This article was first published in the May 11, 2019 issue of the New Zealand Listener.