Fossils


In 1825, Gideon Mantell described fossil teeth and bones from a quarry near Cuckfield in Sussex, England. He named these remains ‘Iguanodon’ meaning ‘having teeth like those of an Iguana’ (a lizard), but he correctly determined that they were quite unlike the teeth of any known lizard or mammal.

He is credited with being the first person to recognise the prior existence of a group of animals that were neither mammal nor lizard and that were subsequently named ‘dinosaurs’ in 1842 (by Richard Owen).

Dr Hamish Campbell writes about Gideon Mantell below:

Gideon Mantell (1790-1852) lived in Lewes near Brighton where he practised as a doctor. He enjoyed a reputation as an outstandingly successful obstetrician; very few mothers or babies lost their lives due to childbirth when he was involved. He was highly intelligent, well-educated and a skilled artisan. However, to the detriment of his marriage (1816-1839) to Mary Anne, he developed an abiding interest in natural history and, in particular, paleontology.

The Country of the Iguanodon, 1837 by John Martin (1789–1854), watercolour. Gift of Mrs Mantell-Harding, 1961. Image © Te Papa.

The Country of the Iguanodon, 1837 by John Martin (1789–1854), watercolour. Gift of Mrs Mantell-Harding, 1961. Image © Te Papa.

On his death, his sons inherited his estate but it was the younger Walter Mantell who ultimately acquired many of his father’s fossil collections, including the famous ‘Iguanodon tooth’ that resides here at Te Papa.

Walter first came to New Zealand in 1839 with the New Zealand Company. He was to spend much of his adult life here and played a significant role in the early colonial development of New Zealand, including the establishment of the Colonial Museum, the original fore-runner to Te Papa. Many descendents of Walter Mantell reside in New Zealand to this day.

The lower jaw of a tuatara (sphenodon). Three teeth are visible along the top. This was the first fossil bone found at St Bathans. Image copyright Te Papa

Recently, a group of researchers in New Zealand suggested that the absence of fossils between 25 and 22 million years ago indicated that the islands completely disappeared under water, and then later re-emerged. But a newly discovered fossil reptile suggests this theory does not hold water. Alan Tennyson, Curator of Fossil Vertebrates at Te Papa, and colleagues, found the remains of a fossilized reptile jaw at St Bathans in Otago.

Curator of Fossil Vertebrates, Alan Tennyson, excavating the St Bathans site in Otago. Image copyright Te Papa

Curator of Fossil Vertebrates, Alan Tennyson, excavating the St Bathans site in Otago. Image copyright Te Papa

The teeth in the fossil jaw and their wear patterns is unique to the tuatara and its ancestors. But what is most exciting about Alan’s fossil is its age: it dates to just 3 million years after a time when other researchers have suggested the land mass sank beneath the waves.

After the ancestral New Zealand continent broke away from Australia and Antarctica, it drifted northwards and, due to a combination of tectonic movements and rising sea-levels, the total land area shrank considerably, but just how small the land area was reduced to is open to debate.

If the entire land area was submerged, the ancestral tuatara discovered by Alan and his colleagues, and all of New Zealand’s biodiversity, could only have arrived after the land re-emerged. To do this, the ancient reptile would have had to cross vast oceans – an unlikely feat for an animal that is a poor swimmer that would have rapidly dehydrated in salt water.

It’s not just the tuatara fossil that suggests New Zealand did not fully drown.

There are many different species in the St Bathans fossil deposit – about 24 species of birds, as well as plants, insects, and freshwater fish. There is no evidence that these species lived in Australia at the time, and most would not have been able to survive a lengthy sea journey. This suggests that ancient New Zealand did not disappear, but remained as an isolated island chain, allowing many species to survive and then repopulate as the continental crust re-emerged.

More information can be found on the Te papa website: http://www.tepapa.govt.nz/TePapa/English/AboutTePapa/Media/OldestTuataraFossil.htm

Reference: Jones, M, E.H.; Tennyson, A.J.D.; Worthy, J.; Evans, S.E.; Worthy, T.H. (2009). A sphenodontine (Rhynchocephalia) from the Miocene of New Zealand and paleobiogeography of the tuatara (Sphenodon). Proceedings of the Royal Society B