Lost and found: 6 rediscovered species (including the tap-dancing spider)

Have you heard of the fat catfish, pink-headed duck or Himalayan quail? If not, that might be because they are lost species – plants, animals and fungi that have been lost to science for at least 10 years, but sometimes hundreds.

Species can become lost for a variety of reasons. Healthy populations can decline due to threats including disease and habitat destruction. They might live in areas difficult for scientists to reach. Or they might have always existed in small numbers in regions where one disturbance could wipe out the whole population.

There are more than 2,200 lost species across 160 countries, according to Re:wild. The wildlife protection and restoration organization has compiled a list of these species, with the hope that finding them will help with efforts to protect and restore our planet’s ecosystems.

While the fat catfish – last seen in 1957 in Colombia – is still officially missing, there is good news for others. Here are six species that have been rediscovered.

Fagilde’s trapdoor spider, endemic to mainland Portugal, was refound after a painstaking two-year search that involved combing forested areas for silk-covered burrows. This uncovered a burrow constructed differently to those typical of trapdoor spiders, and DNA analysis confirmed the female living there was the first Fagilde’s trapdoor spider seen for 92 years. Do they really tap dance? Apparently so – it’s thought that when attempting to attract a mate, the male performs a rhythmic dance at a female’s door.

“We dropped everything and would have gone to the ends of the Earth to see this fish, this legend, alive in the wild,” said one of the researchers responsible for the rediscovery of the leopard barbel in early 2024. Once abundant in the Tigris-Euphrates river system in Eastern Turkey, Eastern Syria, Iran and Iraq, the species was pushed to near extinction by factors including pollution and habitat destruction and was last scientifically documented in 2011. The fish is listed as one of the most endangered in the world – scientists have hailed its rediscovery as an important moment in the fight to protect the region’s freshwater ecosystems.

Once commonly found in the grasslands to the west of Melbourne, Australia, the last confirmed sighting of the Victorian grassland earless dragon was in 1969. That was until 2023, when the tiny lizard, which lacks an external ear opening, was rediscovered in a 'secret' location. The species is listed as critically endangered by local government and officials have declined to reveal the whereabouts of the rediscovered population for conservation reasons.

If any species could be described as interesting, it would be the echidna. It's a mammal. It lays eggs. And it has been called a “living fossil” – its origins stretch back to when dinosaurs walked the Earth. Attenborough's long-beaked echidna, named after the British broadcaster and biologist Sir David Attenborough, is thought to be the most threatened of three long-beaked echidna species. After being lost to science for 62 years since it was last seen in Indonesia, it was rediscovered in 2023.

The critically endangered Jackson's climbing salamander was lost for 42 years. It is a cloud forest species known for being "adept at escaping human attention" – except, maybe, for the one rediscovered in 2017 in Guatemala, which was spotted by a park ranger during his lunch break.

How big can a bee be? At up to 4.5cm long with a wing span of 6cm – about the size of an average human thumb – the female Wallace's giant bee is the largest in the world. It had not been seen in the wild since 1981 and was feared to be extinct. But in early 2019, a team of US and Australian scientists found the species again at the end of a five-day trek in a remote part of north-east Indonesia. Its rediscovery was described as "a monumental moment" that the scientists hoped would spur its preservation.

While the rediscovery of these species can lead to successful conservation, some researchers have noted it is important that efforts focus on all kinds of species, not just those that humans may consider to be more charismatic.

With the world seeing a rapid loss of species between 1,000 and 10,000 times higher than the natural extinction rate, according to WWF, addressing nature loss and degradation is crucial. Not least because over half of the world’s GDP is highly or moderately dependent on natural resources and services.

The World Economic Forum’s Nature Action Agenda is working to unite the public and private sectors in a bid to halt biodiversity loss by 2030. “Business-as-usual is no longer an option,” it says.