Biologists working on the Indonesian island of Sumatra recently encountered a nose-horned dragon lizard which had been lost to science for 127 years.

Sumatra’s indigenous Batak people had depicted a lizard with a pointy horn at the end of its snout, like a rhinoceros, in their artwork for centuries, and it holds a prominent place in their creation stories. But the lizard remained unknown to the rest of the world until Elio Modigliani stumbled across it on an expedition to the shores of Lake Toba – the submerged caldera of the Toba Supervolcano – in 1891. Modigliani preserved the specimen he’d found in alcohol, which faded its brilliant green scales and yellow spikes to mottled blue and white. It was the last member of its species any scientist would see, alive or dead, until 2018.

A Real-Life Cryptid

Based on that single discolored specimen, Modigliani’s lizard became one of five reptile species, along with one amphibian, named after him. Biologists formally named the nose-horned lizard Harpesaurus modiglianii in 1933, a year after its namesake’s death. H. modiglianii is a relative of the more familiar bearded dragon; both are members of the family Agamidae.

It’s a long, low-slung little lizard (males are around 7.7 to 7.9 cm long, not counting the 13.5 cm tail), and it moves with “waggling locomotion behavior similar to chameleons,” according to herpetologist Chairunas Putra. When stressed, its bright green scales turn a rusty brown, and its yellow spines darken to orange. That’s not much information, but it’s more than biologists knew until very recently. By the time H. modiglianii got its scientific name, nobody could actually say for sure whether the species even still existed.

As the decades wore on without another sighting, the uncertainty grew. It’s alarmingly possible for a species to vanish from the Earth without us ever noticing, especially if its numbers are few and its range is small and hard for scientists to survey. Scientists call this kind of disappearance a cryptic extinction, and Modigliani’s lizard was a prime candidate. And it’s not the only one

The Secret Lives Of Lizards

Of the 6,538 known lizard species in the world, 927 of them have only been found on a single 100-square-kilometer patch of land. Lizards, in particular, tend to have small ranges and hide in areas that are hard for human scientists, or even all but the most intrepid local people, to reach. In southeast Asia, some gecko species each live on their own particular rock outcrops, cut off from the rest of the world by the forests around them. If the geckos on any given outcrop die out, the whole species is gone.

And such small, isolated species are especially vulnerable to extinction, because their numbers are already few, and if their habitats are disrupted by climate change, invasive species, and logging or construction, they have no room to spare and nowhere to go. It’s also hard for scientists to know how much danger these species are in, or how to save them, because their small ranges and reclusive ways make them hard to find, much less study.

That’s underscored by another weird piece of data for your next trivia night: 212 lizard species are known to science from just a single specimen or sighting. No one has even seen these lizards twice. (Until the recent rediscovery of Modigliani’s lizard, it was 213 species.) 30 of those species are agamids like Modigliani’s lizard. And it’s likely that there are even more lizard species out there, especially in places like Sumatra, that scientists don’t even know about; some of them may be gone before we get the chance to meet them. Sumatra, in particular, has a wealth of yet-undescribed biodiversity, and new discoveries are happening all the time as more scientists venture into the north and central parts of the island. In just the past decade, biologists have discovered 16 new lizard species on Sumatra; half of them are agamids like Modigliani’s lizard.

H. modiglianii seems to live in an especially tiny corner of the island, just 8 to 12 spare kilometers. It’s an especially precarious little patch of land, at that. “That forest is highly threatened by large-scale exploitation including clear-cutting, and the habitat is highly disturbed by heavy machines,” wrote Putras and his colleagues in the Taprobotanica Journal of Asian Biodiversity. Their estimate is based on their two finds in 2018, combined with another recent report that hinted at an even greater danger to the elusive little horned lizard.

Here Be Dragons

It began as an accidental stroke of luck, although only a biologist would call it luck to stumble across a partially-decomposed lizard corpse. In mid-June of 2018, Putra was surveying the damp, forested hills around Lake Toba when he spotted a dead lizard with a spiky horn on its nose. “From its state of decomposition, we concluded that the specimen had been dead for 2 to 3 days, although it still remained suitable for a full morphological assessment,” Putra and his colleagues wrote. “Curiously, it was not eaten by a predator and the explanation for its death remains unknown.”

Realizing he’d probably found something interesting, Putra sent the dead lizard to a colleague, as one does. Herpetologist Thassun Amarasinghe quickly recognized that he was looking at the remains of something no one had seen since 1891: a Modigliani’s lizard, in the somewhat decomposed flesh. Galvanized by the discovery, Puta plunged back into the Sumatran forest. For five nights, he searched the woods for a live lizard. Like most agamids, H. modiglianii is active during the day, so Putra and his colleagues reasoned that it would be easier to catch one at night.

On the fifth night, luck and perseverance rewarded Putra yet again. Around 9:00 one evening, he spotted a bright green, nose-horned lizard “lying on a low branch, probably sleeping.” He caught the lizard long enough to photograph it, measure every part of its body, and watch its behavior.

“Natural history observations were made by looking with the naked eye at the animal from a distance of at least 3 to 4 m, being careful not to disturb it,” he and his colleagues wrote. They watched as the male lizard hid behind some branches and turned an agitated orange-and-brown, then faded back to bright green as he relaxed again.

It was a thrilling find, but Amarasinghe and Putra decided not to publish it, for fear of drawing pet traders’ attention to the rare lizard. Capturing wild animals for the global pet trade can have a devastating effect on species, especially vulnerable ones like Modigliani’s lizard, whose numbers are small to begin with. Then a social media post changed their minds.

Social Media Complicates Life Again

On December 2, 2019, a Facebook user near the Sumatran city of Berastagi posted a photo of a small green lizard with a horn on its nose. The poster identified the lizard as H. beccari, another nose-horned dragon lizard species – but H. beccari doesn’t live in northern Sumatra. Modigliani’s lizard is the only nose-horned lizard in that part of the island.

“After that social media post, several people found that species (as a trend),” Amarasinghe said in an email. Local pet traders began asking USD$100 for the lizards, and Putra and his colleagues realized that secrecy wasn’t protecting the species after all. “After seeing that social media post, we decided to publish to get attention of the government bodies to take immediate action to protect the species,” he said.

Putra and his colleagues say they hope more surveys will help scientists better understand Sumatra’s biodiversity, and that Indonesian authorities will protect Modigliani’s lizard and other rare species in the mountains around Lake Toba.

“Land management authorities should consider protecting the habitat of H. modiglianii and other such rare mountain taxa, and rigorously enforce existing laws, especially those related to logging,” they wrote.