Fossil Giant Crab

In 1990, a local Whanganui resident captured a giant crab in the Ahu Ahu Valley, inland from Whanganui. That’s a curious creature to find so many kilometres from the coast. It was, however, not a potential family feast. It was a large fossil embedded in a spherical boulder, known in geological terms as a concretion. A concretion is a hard rock that forms around an object such as a fossil, protecting it from damage. Concretions can often be found weathering out of soft mudstone. If a concretion is cut open very carefully, it may reveal an interesting fossil, well preserved within the boulder. Because mudstone is very soft, it can be generally be cleaned off the fossil using water and a stiff brush.


Tumidocarcinus giganteus, giant fossil crab. WRM ref: 2003.42.1

This particular fossil crab was alive approximately 15 million years ago, during the middle of the Miocene period, when the Ahu Ahu Valley, along with the rest of the Whanganui region, was under the sea. It is an example of the extinct species Tumidocarcinus giganteus, a deep-water crab that lived along the seabed in warmer waters than we enjoy today, on the Whanganui coast. During the middle of the Miocene period, which lasted from 24 million years ago to 5 million years ago, temperatures are estimated to have been four to five degrees warmer over most of the planet than they are today, and the sea level was correspondingly much higher.

Large numbers of Tumidocarcinus giganteus fossils have been recovered from the soft papa rock that is characteristic of the hills between Taranaki and Whanganui. Papa is formed from thick muddy sediments accumulating in the ocean around the western coast of the North Island. The numbers of these crabs found indicates that they were a reasonably common species in New Zealand seas during the Miocene. An interesting feature of the Tumidocarcinus giganteus is that the right pincer is usually much larger than the left. On males, the right claw could grow up to twice the size of the left claw. It was probably used for fighting and perhaps for attracting female crabs, as well as feeding.

By discovering fossils, such as this giant crab a very long way from the ocean, we can get a much clearer picture of what the land-masses we now inhabit might be like if the earth’s climate became similar to the middle Miocene again. It is challenging for us to imagine what the planet might be like if temperatures throughout the world continue to rise at the current rate. It is clear, however, that seas will be significantly higher, and much of the New Zealand land mass, especially coastal regions, will probably be under water.

The Whanganui region probably won’t be so great for humans, but giant crabs and other enormous sea creatures might be plentiful again.

Margie Beautrais is the Educator at Whanganui Regional Museum

King Penguin: a Royal Line in Trouble

New Zealand was once home to a gigantic species of penguin, as tall as an adult male human. Like many megafauna species of the planet, this species is now extinct and exists only as fossil remains held in museums.

Two other very large penguins, the Emperor penguin and the King penguin, live in huge colonies around the southern seas. They were so numerous that it appeared there was no risk of them following New Zealand’s fossil Giant penguin into extinction. This, however, may no longer be true of the King penguin. The once numerous bird may be already be an endangered species. The end of the current century, according to scientific research, might signal the end of this royal branch of penguins through the effects of climate change on ocean currents and sub-Antarctic habitats.

1. King penguin with egg

Taxidermied King penguin with egg. Ref: 1802.1688

King penguins live and breed between latitudes of 45 and 55 degrees south, on sub-Antarctic islands and northern parts of Antarctica. The most numerous colony, with about half of the global population of King penguins, has historically been the Crozet Islands in the Southern Indian Ocean. In 1982 the King penguin population of these islands was estimated, through aerial survey, to be around two million individuals. Recent analysis of satellite images taken over the last thirty-five years indicates that the population has plummeted by 90% to around 200,000 birds, with just 60,000 breeding pairs. While this is still a very large number, such a rapid decline is concerning. So what has changed?

Researchers suggest the causes may be overcrowding and the resultant competition for resources; disease such as avian cholera; or the possible arrival of invasive pest species. A non-migratory species, such as the King penguin, relies on the continued health of its sub-Antarctic habitat for survival. King penguins leave their young and swim south to forage for fish and squid along the polar front, where cold, deep water meets more temperate sea.

2. King penguin egg

King penguin egg. Ref: 1802.5822

The research team suspects that climate change could be contributing to the decline, as it has with colonies of penguins in parts of Antarctica. In 1997, a strong El Niño weather event warmed the southern Indian Ocean and temporarily pushed fish and squid, normally eaten by King penguins, further south, beyond their foraging range. The result was population decline for all King penguin colonies in that region. Although El Niño events are cyclical, they can be amplified by global warming. The researchers have concluded that based on current climate change predictions the Crozet Islands, once home to half the world’s population of King penguins will become uninhabitable for these penguins by the mid-century.

With nowhere else to go, the Crozet Islands population of King penguins will be in serious trouble. It would be such a shame if one of the world’s most iconic and loved penguins exists only as taxidermied specimens in natural history museums.


Margie Beautrais is the Educator at Whanganui Regional Museum.

Extinct, stuffed and symbolic

Extinct, stuffed and symbolic

Dr Eric Dorfman’s professional credentials would be a separate – and very long – story. The books he’s written and studies he has made, in themselves, would make a fascinating Midweek article (note to self: write fascinating Midweek article about Dr Eric Dorfman’s books and published studies).

In this issue, however, we treat him as the recently appointed director of the Whanganui Regional Museum and hear about his interest in the long extinct Tasmanian Wolf, Thylacinus cynocephalus.

To do that I had to follow the tall, one-time Californian (but I think New Zealand has claimed him now) down into the bowels of the museum, shuffling between shelves until finding dozens of specimens of the taxidermists’ art. There we encountered our Tasmanian Wolf.

The museum has a stuffed specimen, collected by the museum’s founder, Samuel Drew, sometime around 1891, well before the species met its total demise. It looks its age, poor thing, but the astounding fact is that we have one.

Eric lived in Australia for some years and knows a bit about these creatures. So why did he choose it to present to Midweek?  “It’s immensely cool from the fact that we have an extinct Australian species of which there are only a few in the world and exemplifies the importance of the collection internationally, as well as nationally. It’s cool on a personal level because I’m a conservationist by profession and there is still an effort afoot to see if maybe there are some left in Tasmania … and evolutionarily it’s very cool because although it looks like a dog it’s actually more closely related to a kangaroo, koala or wombat.”

The Thylacine is a marsupial and has a pouch like a kangaroo … well, the female does. The museum’s specimen is an adult male. Eric says they are more closely related to the quoll, another Australian animal, which is “more like a marsupial weasel”.  “From an evolutionary standpoint, this is convergent evolution with a dog,” says Eric. “Also biologically that’s very interesting.  One of my research thrusts is about humans’ relationship with nature,” he says. Eric has a book coming out later this year – Intangible Natural Heritage – of which he is author/editor in league with a team of distinguished authors.

Looking at this sad, stuffed specimen, Eric sees past the obvious and finds a symbol of “our coming of age as a society when we realise that doing this [making animals extinct] is a really bad thing.” He stresses that while this new-found consciousness is too late for some species, it’s not too late for many others.

He praises the work of New Zealand’s Department of Conservation (DOC) and its work here and overseas. “DOC is supporting other countries, including the United States, in methodology of setting up island sanctuaries … and it’s fantastic to be in New Zealand – even though this is an Australian species – from the point of view of this is a place where we have come of age in terms of the environment, and I hope we stay there. You can see why this launches into a lot of really interesting philosophical issues … and also thinking about where museums have been and where they’re going.”

It’s incredible, almost, to realise that Samuel Drew, Whanganui Regional Museum founder, actually helped, in his way, send species such as the huia extinct. He did that by trading stuffed huia (probably) to get an example of another species that, itself, would be extinct in another 50 years. At the time he traded for the Tasmanian Wolf, it was reasonably common but he needed it for his marsupial collection.

“No museum curator has ever intentionally sent a species extinct,” says Eric, “but back in the 19th century when species looked like they were going extinct, often, museum curators would run out to make sure they had them in their collection before anyone else got them … the huia was a victim of that kind of thing.”

The Thylacine was once a pan-Australian species, says Eric, with cave paintings to prove it was once even in the very north of Australia in Kakadu National Park. “By the time Drew was around it was restricted to Tasmania,” he says, although it was being hunted until its final (probable) extinction in the 1930s.

Eric says there is enough genetic material in existence so that, one day, techniques of cloning may be able to reintroduce the species. And so we looked at Samuel Drew’s legacy, part of his vision of a great museum that was all-encompassing.  “We now ‘get’ why he did it,” says Eric, “and we now have this incredible treasure. This is an amazing thing to have.”

There are lemurs from Madagascar and animals from all around the world, some exhibited upstairs, others hiding from the light below decks in the vaults. The Thylacine stands with them, an example of old ethics and philosophies and yet a symbol of what we are today. And if we do manage to clone them back into existence, will we look after them this time? The last word goes to Dr Eric Dorfman.

“If the Thylacine is never going to be reinvented and really is extinct, and the same with the huia, don’t we owe it to the species and owe it to ourselves to allow it to awaken us to the realities of what we’re doing to the planet?”

Original article appeared in the Wanganui Midweek newspaper in June 2011.  Reproduced with permission from the author.

What did the giant eagle look like?

The most commonly seen resonstuction of Harpagornis, attacking adult moa, with plumage like an Australian wedge-tailed eagle. Pic: John Megahan / Wikipedia

The most commonly seen resonstuction of Harpagornis, attacking adult moa, with plumage like an Australian wedge-tailed eagle. Pic: John Megahan / Wikipedia

New Zealand was once home to the largest eagle in the world, Harpagornis moorei, often known as Haast’s eagle. I’m not a fan of that name: Julius von Haast was the Director of the Canterbury Museum and the first to scientifically describe the eagle, from bones collected from a North Canterbury swamp, in 1871. But getting an eagle named after yourself seems a trifle vain, so I prefer to call it the New Zealand eagle or the giant eagle, both of which are more descriptive.

Harpagornis is a marvellous name: “grappling-hook bird”, for its enormous clawed feet. What its Māori name was we’re not sure: pouakai and hokioi have both been recorded, but by the time written transcripts were being made the eagle had been extinct for centuries and had entered the realm of legend.

Wedge-tailed eagle (Aquila audax). The largest eagle in Australia, and capable of taking down a kangaroo, the wedge-tail has a typical eagle skull and head feathers, relatively short compared to a New Zealand eagle. Photo: Sam Schmidt / Flickr

Wedge-tailed eagle (Aquila audax). The largest eagle in Australia, and capable of taking down a kangaroo, the wedge-tail has a typical eagle skull and head feathers, relatively short compared to a New Zealand eagle. Photo: Sam Schmidt / Flickr

Recent examination of its DNA shows that the New Zealand eagle was most closely related to the Australian little eagle (Hieraaetus morphnoides), the smallest eagle on that continent. Its ancestors were blown to New Zealand and increased in size tenfold within a million years, an extraordinarily-rapid increase. Giant eagles weighed about 10kg in males and 14kg in females, nearly half as large again as the largest eagles alive today. They were big enough to kill adult moa—we’ve found the claw marks in moa pelvic bones. And they would have been very capable of killing humans too, which is probably why they were wiped out quite quickly, along with moa, soon after Polynesians arrived in New Zealand.

One account of the eagle, collected by Sir George Grey from a Ngāti Apa elder around 1850, describes it as living in the mountains, having red, black, and white feathers with a red crest, and being as big as a moa. The problem with this account is that giant eagles never, as far as we know, lived anywhere near Ngāti Apa in the Whanganui or Manawatu area. All the fossils we’ve found are from the eastern South Island and Southern Alps. So this centuries-old tradition is unlikely to be based on eye-witness accounts.

3. attenboroughOlder reconstructions of the giant eagle, based on this 19th century description, show it with lurid red plumage and a pointed crest. Its closest relative, the little eagle, is a rather more inconspicuous rusty brown. Most recent depictions give it the brown plumage of an Australian wedge-tailed eagle. Almost none of the reconstructions, however, get the head right: the giant eagle had an extraordinarily long skull, half as long again as you’d expect from a bird its size. The recent David Attenborough documentary set inside the Natural History Museum included a computer-animated Harpagornis, but it was really just a scaled-up golden eagle, with long narrow wings and a too-short skull.

(Attenborough was rather guilty of exaggeration when he described the eagle, in breathless voice-over, as having “a beak the size of a butcher’s cleaver”. Its beak is actually about 7 cm long, the size of my little finger or a paring knife.)

1. eaglevulture-sketchThe giant eagle’s extremely long bill, with small bony flaps protecting the nostrils, is actually rather like that of some species of Old World vultures. A vulture’s elongated bill is an adaptation for sticking its head inside the messy carcasses of animals much larger than itself. Most eagles don’t need such bills, because they’re feeding on relatively small prey. But giant eagles were killing moa 15 times their size, so their feeding would have been similarly messy. Not only did they have the elongated beaks of vultures, they perhaps had the short head feathers or even bald heads of them as well.

Griffon vulture (Gyps fulvus) have shorter, finer feathers on their head and neck (sometimes bald) and protected nostrils to prevent clogging. Photo: mhx / Flickr

Griffon vulture (Gyps fulvus) have shorter, finer feathers on their head and neck (sometimes bald) and protected nostrils to prevent clogging. Photo: mhx / Flickr

Ornithologists who study the New Zealand eagle get defensive when you suggest it may have had a head like a vulture. For decades, Harpagornis was victim of a terrible slander: its short wings supposedly meant it was on its way to becoming flightless, and it thus must have spent most of its time on the ground scavenging moa carcasses. In fact, short wings are a characteristic of forest eagles that need to maneouver around trees, not soar for long distances. And the discovery of claw marks on moa bones show that Harpagornis was indeed killing its own prey. But it took quite some time to dislodge its reputation as a scavenger, and a vulture-like reconstruction would hardly help.

Whether the New Zealand eagle had a bare head, or indeed a fancy red crest, is ultimately something we can’t determine from the few remaining bones. Māori rock art depictions of eagles are too stylised to help. Nobody has seen one for 500 years. Perhaps one day a mummified skull with feathers will turn up, as has happened with moa. But ultimately we have to make our own estimate of what’s probable, and rexognise that all depictions of a long-extinct creature, however convincing, are mostly well-informed guesses.

Dr Mike Dickison is Curator of Natural History at the Whanganui Regional Museum.

Native Fishes of the Whanganui

A native grayling recently rediscovered in the collection, caught in the 19th century.

A native grayling recently rediscovered in the collection

New Zealand is famous for its extinct birds, but not many people know we have an extinct fish. The native grayling or upokororo (Prototroctes oxyrhynchus) was found in many rivers and streams, including the Whanganui basin. The size of a small trout, it was good eating and extensively fished by Māori and pākehā. By 1900 it was rare, and it disappeared in the 1920s.

Remarkably, we recently came across a native grayling in our collection. Some time in the 19th century it was skinned, stuffed with cotton wool, and mounted on a board (originally painted blue, from the traces of blue paint on the fish’s back). At nearly 30 cm long, it’s one of the largest specimens known.

It’s hard to imagine what the Whanganui River was like at the time that grayling was stuffed and mounted. The first pākehā settlers described the banks as steep and lined with piles of sunken logs. When this wood was dug out for building, the banks eroded back a chain (about 20 m) on both sides. A century ago, a newspaper accounts tells us, the Whanganui was clear enough for someone to find a wedding ring on the river bed that had been dropped from the town bridge; imagine trying to find anything dropped into the river today! There were numerous side streams, even in the middle of town, that have since been covered over and culverted.

The Giant kokopu (Galaxias argenteus)

The Giant kokopu (Galaxias argenteus)

The river and side streams would have teemed with native fishes. Not just eels, but īnanga (the main whitebait species) and many different kinds of kokopu. The largest was the giant kokopu, growing over 40 cm long and weighing up to 2 kg. We only know that giant kokopu lived here because the museum has one, preserved in alcohol, caught at Kaitoke in 1948. Who knows how much longer they hung on in the area before being wiped out by agriculture and overfishing?

The kokopu pool near Karaka Street

The kokopu pool near Karaka Street

Even today, you can still find native fishes in some of the remaining urban streams in Whanganui. Īnanga and eels live in the creek running behind Aramoho School, and rare freshwater mussels are still surviving in the Matarawa Stream that flows through Kowhai Park. The swampy wetland behind the houses in Karaka St drains into a small stream, which was originally created as a drainage ditch but turns out to have the largest population of banded kokopu (Galaxias fasciatus) we’ve yet found in the Whanganui area.

The banded kokopu (Galaxias fasciatus)

The banded kokopu (Galaxias fasciatus)

As part of River Week, local fish expert Stella McQueen and I ran a night-time fish-spotting expedition to Karaka Wetland. Most native fishes are nocturnal, so can only be caught with headlamps and nets. We caught, measured and photographed banded kokopu (some up to 24 cm) long and released them into the stream again, except for two, which are on display in our aquarium in the Museum atrium.

Raising awareness of native fishes is part of our job; these are taonga, some of them threatened or endangered, literally living in our backyards. They’re incredibly vulnerable: vandals, eel fishers, or someone thoughtlessly dumping a drum of paint thinner could wipe out a streamful of fishes that have hung on right through Māori and European settlement, from a time when the Whanganui and its streams only flowed through swamp and forest.

Dr Mike Dickison is Curator of Natural History at the Whanganui Regional Museum.

Stories from bird bones



Most of us associate kea with holidays in the Southern Alps. When you stop the car at Arthur’s Pass a few of these parrots will normally arrive to fearlessly beg for food. Cars and food are so strongly associated in their minds that they’ll tear the rubber trim off your vehicle in the hope that snacks might be found somewhere inside. Kea are remarkable birds, intelligent and inquisitive, and are famous among ornithologists for being the world’s only alpine parrot.

To a palaeontologist, though, kea aren’t alpine parrots at all. Fossil kea bones, many just a few hundred years old, have been found in lowland sites thoughout Canterbury and Otago right down to the coastline, showing the birds were living in coastal forest before humans arrive. Even today, kea live year-round in forest in parts of the West Coast. And new research has identified kea bones from swamps and sand dunes in Hawkes Bay and the Wairarapa, so it seems likely that were living in North Island forests as well.

Kea, Kākā, and Chatham Kākā  skulls

Kea, Kākā, and Chatham Kākā skulls

So where did all the kea go? They were probably wiped out by the first human settlers and the rats that accompanied them around 700 years ago, disappearing from the North Island and most of the South Island. The only reason kea aren’t extinct is that the Southern Alps are inhospitable to both rats and humans. But the upside is that kea could likely be reintroduced to North Island forests where there’s sufficient predator control—good news for mainland islands like Zealandia and Bushy Park.



Kea are not the only case where fossil bones tell us where a species used to live. Huia at the time of European settlement were restricted to the south-eastern North Island, mostly in the Tararua, Ruahine, and Rimutaka ranges. But their bones have been found right up to Northland, and they were probably found throughout the island before human hunting made them rare (and, by about the 1920s, made them extinct).

Takahē were once found throughout the South Island. Thought to be extinct by the 20th century, they were famously rediscovered in an Fiordland valley in 1948. Their northern cousin, the moho or mohoau, is known only from fossil bones from all over the North Island, although a single live bird was caught in the Tararuas in 1894. Both takahē and moho were the giant flightless descendants of pukeko, and both were driven almost to extinction in pre-European times; it’s just a fluke that the South Island takahē managed to survive while their relatives went extinct. Like the kea, takahē persisted in an inhospitable environment, but they much prefer living in lowland forests, given how well they do on offshore islands and mainland sanctuaries.

Chatham Kākā

Chatham Kākā

Fossils not only shed light on living species; they sometimes reveal brand new ones. For years, palaeontologists had been turning up bones of kākā in the Chatham Islands, except these kākā had unusually long beaks; almost as long as a kea’s. After comparing bones, they realised the Chatham kākā was a completely separate species: a ground-dwelling version of the mainland kākā, wiped out soon after humans arrived in the Chathams. The Chatham Islands turn out to been like mainland New Zealand in miniature, full of species found nowhere else. The islands had their own species of pigeon, robin, fernbird, penguin, bellbird, swan, coot, and other flightless rails; most of these are now extinct or endangered, a few, like the Black Robin, were rescued in the nick of time.



It’s remarkable that we’re still making discoveries about some of our most well-known native birds, from such inconspicuous things as tiny fossils. Only a handful of scientists are doing this work, and it’s not well-supported—some of our palaeontologists have had to move to Australia to get funding. It’s taken years for conservation workers to incorporate fossil evidence into decisions about which species should be translocated where. But it’s important that institutions like museums keep doing it: a large part of the prehistory of New Zealand is a story told by little bones.


Dr Mike Dickison is the Curator of Natural History at the Whanganui Regional Museum.