Top 25 Most Wanted Lost Species
Eight new wild and whimsical lost species from around the world have claimed a spot on Re:wild’s top 25 most wanted lost species list as part of our Search for Lost Species program—the Guinness World Record-setting quest to find and protect species lost to science. The new species replace those that have been rediscovered—often catalyzing conservation actions—since the program’s inception in 2017. They span species groups, geography and habitat, and include the most wanted list’s first fungus, arachnid, and lost species native to the United States.
Many thanks to artist Alexis Rockman for bringing these lost species to life.
What’s in a name?‘Fat Catfish’ almost says it all. This lost fish species has more rolls than a used tire. The Fat Catfish has only ever been found 9,800 feet high in the Andes mountains, in Lake Tota, where locals call it “Pez Graso,” which can also be translated to “grease fish” — a name, perhaps, both apt and foreboding for a combustible fish. Yes, you read that right. Before the Fat Catfish became a lost species, local people sometimes burned its fat for fuel in their lamps. The mystery of their disappearance, however, remains unanswered. The Fat Catfish was described for the first time by ichthyologist Cecil Miles in 1942, and the last known individual was collected from the wild in 1957. Only nine other individuals had been recorded before then.
The Fat Catfish is also one of the top 10 most wanted freshwater fishes by the Search for Lost Fishes, an extension of the Lost Species program by Re:wild and Shoal. Expeditions in search of the Fat Catfish kick off in 2022, with expert advice from Dr. Ian Harrison, who was involved in a trip in search of the species in 1999 and once described the fish as “the closest a fish could get to the Michelin Man.”
Find out more about the Search for Lost Fishes.
The Togo Mouse was discovered in 1890 in a single location. The two individuals collected at the time are the only clues we have about this species’ natural history because it hasn’t been recorded since. Researchers think the Togo Mouse may occupy parts of Ghana, as well as Togo. Contents found in the teeth and stomachs of the individuals collected indicate that the Togo Mouse’s diet includes insects. Its short tail suggests ground-living rather than a life spent up in the forest canopy.
Two expeditions failed to rediscover the Togo Mouse in the 1990s. Recent interviews with hunters in Ghana suggest local knowledge of the Togo Mouse as recently as 2011. The hunters believe that their activities caused several local small mammal populations to fall, including Togo Mice. Field staff in the Kyabobo Range National Park, 12 miles west of the site of the Togo Mouse’s original discovery, also say they recognize the species when shown pictures, as do locals, calling it “Yefuli.” There is a pressing need to survey likely forest locations in both countries. Eighty percent of West Africa’s rainforests have already been degraded or cleared for agriculture. We need to act soon to protect any remaining Togo Mouse populations from losing the rest of their forest home—but first we need to make sure they are still around.
One of the first mammals to be described from a fossil alone, the Dwarf Hutia looks like a guinea pig–esque rodent that once lived all over Cuba and the nearby Isle of Youth. It was last captured by researchers in 1937, but some suspicious poops found in 1978 might have been enough to prove that it’s still out there! If it does still exist, the Dwarf Hutia would most likely be living in the uber-remote Zapata Swamp, and there are probably only a handful of them left. Unlike other rodents that often have many offspring in a litter, a Dwarf Hutia that was brought into captivity back in the day only gave birth to one baby.
What wiped these little guys out? The list of threats to their survival is unfortunately long, starting with invasive species. The Dwarf Hutia had to compete with Black Rats for habitat and food; they also became prey for animals like mongooses and the invasive Walking Catfish, one of the most notorious predators in the Zapata Swamp. Much of their habitat has been destroyed by human hands, or by accidental fires. If we have any chance of uncovering the Dwarf Hutia, we need to better survey Zapata Swamp and manage its invasive species.
The South Island Kōkako was last seen in 2007, which makes it one of the most recent species disappearances on our top 25 most wanted lost species list. The South Island Kōkako, also known as the Orange-wattled Crow, made headlines in 2007, the last officially accepted sighting of the species. The accepted record before that was in 1967. Based on this sighting, in 2013, the New Zealand Department of Conservation overturned its 2008 decision to declare the species Extinct. Today, this bird’s IUCN Red List status is Critically Endangered (Possibly Extinct). The South Island Kōkako is known for its haunting, melancholy yet melodious song, with calls that include rich flute and organ notes. If one day this species is rediscovered, New Zealand conservationists believe they can bring it back from the brink of extinction in the same way they helped revive its sister species, the North Island Kōkako, and other native birds including the Kākāpō, Takahē, Black Robin and the Chatham Taiko.
The Blanco Blind Salamander is so rare that it has only been found once—in a spot slightly northeast of San Marcos, Texas. It was discovered back in 1951 by workers excavating a small crevice with flowing water in the bed of the then-dry Blanco River. Over the years, the river has changed course, and the spring where they are found is buried under gravel and sediment today. Only four individuals were found at the time of their scientific discovery, and none have been encountered since. The good news is: If any species were going to survive being plugged back into a river orifice, it would probably be the Blanco Blind Salamander. The Blanco Blind Salamander breathes through its skin gills, is depigmented, and likely preys on groundwater invertebrates and even other salamanders in the aquifers where it lives. Threats to this species include declines in the quality and quantity of groundwater on which it depends, small population size across an extremely limited distribution, and contamination of groundwater habitats from surface sources. With the help of our partners who have already started the search, we aim to find out!
Fagilde’s Trapdoor Spider was described for the first time in 1931 based on two females collected outside a small village in north-central Portugal. No males have ever been found — as far as we know, but males of this group wander in search of females, and tap dance at the female’s door to mate. If this species survives today, there’s a chance locals might have seen them without knowing what they were looking at (including in their own homes!). In 2011, Dr. Sergio Henriques uncovered clues to the whereabouts of Fagilde’s Trapdoor Spiders, and insights into their secret lifestyles, hidden underground. Unlike other Nemesia spiders, which make their homes in vertical traps, perpendicular to the ground, young Fagilde’s Trapdoor Spiders build their traps horizontally. It is the only Nemesia spider we know of that does this.
In a 2021 expedition, Dr. Henriques returned to the search and found spiders, but still must confirm whether this is our coveted spider species or another Nemesia spider. Though his team found more tantalizing clues and one trapdoor spider, future expeditions will reveal whether this is our lost spider species or a different species. Many lost species require several searches over many years to find! The Fagilde’s Trapdoor Spider is vulnerable to wildfires, agriculture, and urban development, but hope remains as long as there are arachnologists out there to help look for this fuzzy tap-dancer.
The Big Puma Fungus — otherwise known as Nahuelbuta Austroomphaliaster (try saying that five times fast, or even once!) — is officially the first-ever member of the fungi kingdom to feature on Rewild’s 25 most wanted lost species list. Described for the first time in 1988 by Garrido in Bibliotheca Mycologica, this fungus is endemic to the Cordillera de Nahuelbuta a mountain range in the temperate forest of South America, with which the fungus also shares a name. In the Mapuzungun language nahuel is the word for “puma,” and buta is the word for “big.” Not much is known about the Big Puma Fungus, which is one of the reasons we are SO excited by the possibility it may be rediscovered again by some of the world’s most tenacious mycologists — experts and aspirants are both welcome. One of the things we DO know is that Austroomphaliaster is currently considered a monotypic genus, which means that the Big Puma Fungus might be the only one of its kind out there.
A world of mystery surrounds the Pernambuco Holly, a species of holly tree endemic to Brazil that has evaded scientists for almost two centuries. It is known only from one sample collected from an obscure location in the Atlantic Forest, which stretches along the Atlantic coast of South America. When the first colonists arrived half a millennia ago, the Atlantic Forest was estimated to cover an area of at least 390,000–580,000 square miles. Today, more than 85% of it has been lost to deforestation as forest has been transformed into pasture for cattle and sugar cane plantations.
Pernambuco Holly is believed to inhabit a very small corner of the Atlantic Forest, where it awaits rediscovery by a group of tenacious explorers.
If Attenborough’s Long-beaked Echidna is still out there, it is one of just five surviving species of monotreme, an ancient clade of egg-laying mammals found only in Australia and New Guinea, whose origins go back to the Jurassic era some 160 million years ago. This species is the smallest and likely most threatened of three long-beaked echidna species, and is known only from a single individual collected by a Dutch botanist during an expedition to the Cyclops Mountain in 1961. Interviews with locals suggest that the animal may still be present in the mountains.
The Ilin Island Cloudrunner is only known from one individual purchased at a market on the Philippines’ Ilin Island. The species was “found” in the collection at the Smithsonian National Museum of Natural History decades after it was donated. Although surveys with local communities have not revealed knowledge of the species, there are some unverified reports from Mindoro. Scientists don’t know anything about the cloudrunner’s habitat or ecology, but are eager to learn in order to best safeguard the species.
In 2019, Re:wild funded two rounds of camera-trapping work by the Mindoro Biodiversity Conservation Foundation, Inc. (MBCFI). These were the first surveys specifically organized to search for this species. Although there was no sign of the cloudrunner this time, Re:wild has already helped MBCFI set up more camera traps for an extended period of time to continue the search. Stay tuned!
Learn more about the Ilin Island Cloudrunner.
Much mystery has traditionally surrounded this lost species. When the kangaroo was found in the Wondiwoi Peninsula of West Papua in mossy montane forests at an elevation of 1,600 meters, scientists couldn’t figure out how it came to inhabit the higher parts of the Wondiwoi Peninsula—the answer remains elusive as an enduring “zoo-geographical mystery.” Everything we know about the Wondiwoi Tree Kangaroo comes from a single individual, an adult male collected in 1928 by one of the world’s leading evolutionary biologists, Ernst Mayr.
In 2018, a tourist in West Papua took low-quality photos of a species that could possibly be the Wondiwoi Tree Kangaroo. Re:wild is in the process of preparing an expedition with the University of Oxford and local conservation partners to verify the sighting and to confirm that this lost tree kangaroo species is still out there. It is imperative that conservation measures are put in place to protect the species once the rediscovery is confirmed through scientific techniques, such as DNA sampling with appropriate permits.
The 21 species of golden moles, most of which occur only in South Africa, show many unique traits. They have an oily secretion that lubricates the fur with an iridescent sheen and gives rise to the name "golden mole," even though most are not golden in color. They have distinctive skeletal characteristics that enhance hearing underground so they can detect prey (since they are blind) and very unusual brain anatomy suggesting advanced navigation abilities based on a "sixth sense" that allows them to remember muscular activity patterns, known as "kinesthesia."
De Winton's Golden Mole is particularly threatened because it occurs in a very small area where natural habitat is threatened by large-scale alluvial diamond-mining operations. Re:wild has partnered with South Africa's Endangered Wildlife Trust to use new techniques in search of the lost mole, including eDNA, thermal imaging and scent detection using a trained sniffer dog. In 2021, the team collected more than 100 soil samples from different sites in Port Nolloth on the northwest coast of South Africa. They are testing the samples for environmental DNA (eDNA), hoping to discover if the golden mole they have detected is De Winton’s Golden Mole or a new species to science.
Miss Waldron’s Red Colobus came close to claiming the dubious honor of being the first primate to be declared extinct in more than 500 years after repeated failed searches. But evidence from hunters appeared in 2000 and 2001 that suggested that a very small number of these monkeys may be living in the southeast corner of Côte d'Ivoire. It was first discovered in 1933 by a British museum collector who named it after a colleague on the expedition, Miss F. Waldron, with the last conclusive sighting of the monkey in 1978. No photographs or video of the species alive exist.
Although the quest to find Miss Waldron’s Red Colobus Monkey with partners the Swiss Center for Scientific Research in Côte d’Ivoire and Florida Atlantic University has not yet uncovered photographic evidence of the monkey in question, it has produced striking footage of other rare and endangered primates. This includes the Critically Endangered White-thighed Colobus, Endangered White-naped Mangabey, and the first-ever video of a Critically Endangered Roloway Monkey in the wild, captured high in the canopy of Côte d'Ivoire’s Tanoé-Ehy Forest in west Africa. Upcoming expeditions will focus on searching for this lost primate closer to the interior of the swamp.
The Namdapha Flying Squirrel is only known with certainty from a single individual collected in Namdapha National Park, the largest protected area in the Eastern Himalaya biodiversity hotspot, at altitudes of between 100 and 350 meters (or between 328 and 1,150 feet) above sea level. Although researchers have surveyed the surrounding area for the flying squirrel, there have not been any verified sightings of the species. Scientists believe this lost species occurs in dry deciduous montane forests along streams, and may be restricted to the area of a single valley within the Namdapha National Park. Aaranyak has started nighttime spotlighting—shining lights into the treetops to look for the reflection of animals’ eyes—and will continue the search in the first few months of 2022. Stay tuned!
Himalayan Quails have distinctive red bills and legs, black faces and throats with white foreheads. They infrequently fly, and usually only when flushed. This medium-sized quail belongs to the pheasant family and is known from only two locations in India. The species was first described in 1846 by J. E. Gray from living individuals in the collection of the Earl of Derby at Knowsley Hall. It was not found in the wild until 1865, when Kenneth Mackinnon shot a pair of quails. It was last seen only about a decade later.
The Himalayan Quail is also one of the top 10 most wanted lost birds by the Search for Lost Birds, a Lost Species partnership with Re:wild, American Bird Conservancy and BirdLife International.
If the New Zealand Greater Short-tailed Bat still exists, it could be the come-back kid. This species—one of three of New Zealand’s bat species—vanished from New Zealand’s North and South islands following European arrival some 200 years ago. It was subsequently restricted to small predator-free islands until rats were accidentally introduced in 1963. Because this bat species spends an unusual amount of time on the ground, it’s especially susceptible to rats, and the introduction of the invasive species devastated the bat’s remaining population. Rats have since been eradicated from both Big South Cape and neighboring Putauhina Island, and since then there have been several unconfirmed sightings in both places. And in 1999, Mystacina-like echolocation calls were recorded from Putauhina.
The rediscovery of this lost toad could be the key to better understanding how species rebound from the chytrid fungus that has decimated amphibians worldwide and hit harlequin toads particularly hard. The Scarlet Harlequin Toad has the most restricted geographic range of any Venezuelan Atelopus species and is known from a single stream in an isolated Venezuelan cloud forest. Anecdotal reports from locals indicate that it could be surviving in a remote patch of cloud forest that researchers have not yet surveyed. A 2020 Re:wild-supported expedition by the Rescue of Endangered Venezuelan Amphibians (REVA) did not uncover the lost toad, but we haven’t given up hope and will team up again to explore similar habitat nearby.
The Pink-headed Duck was always considered rare, but it has not been conclusively seen in the wild since 1949 in India and is known from Myanmar from only two individuals. Unconfirmed reports of Pink-headed Duck sightings in 2006 spurred conservationists to continue to look for it and to try to capture the first photos of a live bird, unsuccessfully. In addition to the deep pink head and neck found on male ducks, these birds lay spherical eggs and likely live in tall, thick elephant grasslands, swamps and floodplains.
In 2017, the Pink-headed Duck eluded a Search for Lost Species expedition team in Kachin State in Myanmar. The team’s interviews with locals suggest that the bird likely spent time at Indawgyi Lake more recently than the last record of the species in Myanmar in 1910, maybe as recently as 2010. Re:wild is supporting expedition team leader Richard Thorns to plan another expedition in 2022, this time to set camera traps in search of evidence that the flashy duck is still out there.
EXPEDITION TEAM MEMBERS INCLUDE: RICHARD THORNS
Wellington’s Solitary Coral is an endemic species from the Galápagos Archipelago in Ecuador, recorded between two and 43 meters (or six and 140 feet) underwater. Before 1982, this species was considered abundant at some sites, but the El Niño event of 1982 and 1983 destroyed most colonies of this species, except for two populations. But since 2000, scientists have not found the coral even at those two sites, indicating that the species is particularly sensitive to changes in the temperature of water in which they live.
The only known individuals of this pygmy seahorse were collected on the coast of Eden, Australia, but the Bullneck Seahorse has never been seen in the wild. Scientists believe it lives in sand beds at the bottom of the ocean (more than 325 feet underwater) and may inhabit gorgonian corals. No information is available about the Bullneck Seahorse’s population density, distribution, ecology, behavior, population trends, genetic structure or life history traits. Dedicated field surveys will require scuba diving and fisheries sampling.
This is one of the most endangered rabbits in the world as the result of poaching and habitat destruction. The species, which likely lives in a small, semi-isolated mountain range in the Sierra Madre del Sur, Guerrero, Mexico, is known from only four individuals, the most recent just a skin donated by local hunters in 1998. There are no known photos of this species.
Between August and November of 2019, a team of researchers and local guides set out to look for the rabbit on several multi-day expeditions. Although they didn’t find the animal then, they plan to continue the search in Omiltemi and four other villages, using camera traps and DNA from dung to obtain evidence that the species is still around. The search will continue in 2022, so stay tuned!
The Pondicherry Shark is a small and stocky gray shark. This species does not grow any longer than about one meter, or three feet, long. The shark was once found throughout IndoPacific coastal waters, from India and possibly extending to the Gulf of Oman into Southeast Asia, and is known to enter freshwater. It may also be found in rivers such as the Hooghli River and Saigon River.
In 2019, Discovery Channel’s Shark Week special, ‘Extinct or Alive: The Lost Shark,’ featured what seemed to be a potentially promising finding of a shark in a remote seasonal fishing village in Sri Lanka. While the finding was publicized as the rediscovery of the Pondicherry Shark, it was not accompanied by any molecular evidence. Based on the photos from that expedition, scientists are confident that they are photos of a different species, the Spot-tail Shark.
The striking Syr Darya Shovelnose Sturgeon is endemic to the Syr Darya River, and was once found in Kazakhstan, Tajikistan and Uzbekistan. It is among the smallest sturgeon species in the world, growing only up to about one foot long. It was once found in the Aral Sea, but according to NASA, the Aral Sea shrunk by more than 60% between 1973 and 2000. The Aral Sea is now hypersaline and as a result, doesn’t harbor any fish, aside from in a small reservoir. The river has also experienced large levels of water extraction, damming and agricultural pollution. The sturgeon has been listed in the Red Data Book of Kazakhstan since 1978 and has also been featured on stamps.
Although a Re:wild-supported expedition team from the Tennessee Aquarium, Eurasian Regional Association of Zoos and Aquariums, and Kazakhstan Fisheries Research and Production Center was not able to rediscover the species at the end of 2018, what they did find has spurred hope that they’ll succeed on future trips. Expedition team members included Dr. Bernie Kuhajda and Alexey Chernyak. We’re hoping to work together in 2022 and 2023 to solve the mystery of this lost sturgeon once and for all.
The Syr Darya Shovelnose Sturgeon is also one of the top 10 most wanted freshwater fishes by the Search for Lost Fishes, an extension of the Lost Species program by Re:wild and Shoal.
EXPEDITION TEAM MEMBERS INCLUDE: BERNIE KUHAJDA, ALEXEY CHERNYAK
This beautiful tropical parakeet is only known with certainty from the Sinú Valley in northern Colombia. BirdLife International estimates that if the bird is not already extinct, no more than 50 likely exist. Despite extensive searches, there have been no confirmed records of the parakeet since 1949. Scientists know very little about the Sinú Parakeet’s reproductive physiology, nutritional needs, ecology or behavior. There are 18 individuals known from four locations in Colombia, two of which have been deforested.
During a 2021 expedition to Alto Sinú in search of the lost parakeet, an expedition team found dozens of species new to Colombia’s Córdoba Department. Local communities will continue the search and Re:wild partners are hoping to get back out into the field again in 2022 for another expedition to find the lost bird.
Except for one or two individuals imported for the pet trade, Zugs’ Monitor is completely unknown. It is rarely—if ever—seen by locals, and scientists know nothing about its ecology or natural history. It comes from the Moluccan Islands of East Indonesia, where the number of new Varanus species discovered has increased significantly in recent years. The rainforests of Halmahera Island are a biodiversity hotspot and home to several endemic species.