Ten of New Zealand’s forgotten species

From a list of hundreds, Charlie Mitchell highlights 10 of our native species on – or possibly beyond – the brink of extinction. Some are so rare they live only in one patch of grass, or beneath a single rock.

Open Bay Island Leech

In the early 20th century, a botanist looking for weta on Open Bay Island, off the coast of Haast, was bitten on the hand. The culprit was a leech species.

Eighty-four years later, a scientist was photographing penguins under a boulder on the island when he was bitten on the eyelid. The leech had re-emerged.

Few species are as elusive as the Open Bay Island leech, which feeds on the feet of nesting birds, specifically penguins. The last time one was seen was in the 1990s, when the world’s entire known population appeared to be living beneath a single rock.

Hamilton’s Frog

New Zealand’s four endemic frogs are small, don’t croak, and don’t have a tadpole stage – they grow in small gelatinous sacs and hatch as froglets, effectively miniature frogs.

Hamilton’s frog is the largest of our frog species, and the rarest. Almost the entire population lives on what is known as Frog Peak on Stephens Island, in Cook Strait.

The Eyelash Seaweed

The red, stringy seaweed is both the size and shape of an eyelash, and appears only at certain times of the day. It was discovered in 2005, and has been found only in Kaiko¯ ura – more specifically, on two individual boulders, each on a different part of the coast.

Teviot Flathead Galaxias

While only one native fish species has been known to have become extinct (the grayling – ironically, our only fish with specific protection), the Teviot flathead galaxias is the closest to joining it.

The small fish is found only in a few streams near the Teviot River in Central Otago. Its habitat covers an area roughly the size of half a rugby field, most of which is on private land.

Tepakiphasma Ngatikuri

Only two of these stick insects have ever been found, both in Radar Bush at the northernmost tip of the North Island.

New Zealand has 23 known stick insect species, but Tepakiphasma is notably different from other New Zealand stick insects – it has more teeth on its claspers, and its egg has a perforated cone.

Three Kings Kaikomako

The small tree with glossy green leaves is endemic to one of the Three Kings Islands, north of Cape Reinga. They were probably widespread on the island before the introduction of goats, which ravaged the species until only one tree remained, on a steep slope near the peak of the main island.

Because the tree was female, and did not produce seed, it was thought to be the last tree that could exist. But after several decades, researchers managed to get the plant to produce seeds, and the species was cultivated.

Titanomis

The giant moth is one of our greatest conservation mysteries. Only 10 have been found, the last of which was caught in 1959, trapped in the floodlights at Waipapa Dam in Waikato.

Attempts to categorise the moth have been unsuccessful, as it does not appear to have any close relatives. The 10 confirmed sightings range over 80 years, in all parts of the country.

It may be extinct, but there are species that have been rediscovered after a longer period of absence, such as the giant moehau weta.

Bartlett’s Ra¯ta¯ and the Spirit Liverwort

Bartlett’s ra¯ta¯ was discovered in 1975, in a surviving forest remnant in the Far North. It can grow up to 30m tall and has greyish bark, which flakes off easily.

Its wild population is found only in three forest fragments near Spirits Bay, at the very top of the North Island. At last count, there were only 13 trees left, most on private land.

But if the Bartlett’s ra¯ta¯ is rare, it doesn’t compare to a plant that exists only on its branches. The spirit liverwort was discovered in 2005, and is one of our 24 native liverwort species.

Cobble Skink

It had one of the easiest descriptions for a species’ home range you could imagine: ‘‘Behind the Granity pub.’’

The cobble skink was discovered in 2007, on a stretch of sand at Granity, on the West Coast. Once it was probably spread widely on West Coast beaches. As of 2017, 40 cobble skinks were known to exist, all literally behind the pub.

Last year, the entire population was captured and relocated to Auckland Zoo. It was fortunate timing – earlier this year, a storm swept through Granity, and likely would have destroyed the skinks’ habitat.

Mokohinau Stag Beetle

The flightless beetle exists only in one patch of grass on an island known as Stack H in the Hauraki Gulf. It is unknown how many individual beetles remain, but their patch of grass is roughly the size of a living room.

The species was devastated by introduced rats, which made it to every island in the group except Stack H. It is one of our largest beetle species – males can grow to 3cm long.