Smallest Known Lizard Found in Caribbean

Bijal P. Trivedi
National Geographic Today
December 3, 2001
On the remote Caribbean island of Beata in the Dominican Republic,
scientists have discovered what appears to be the world's tiniest
species of lizard.

At a miniscule 16 millimeters (just over half
an inch), the dark brown lizard is small enough to curl up on a dime or
stretch out on a quarter.

The dwarf gecko was named Sphaerodactylus ariasae in honor of herpetologist Yvonne Arias, a proponent of conservation efforts in the Dominican Republic. Other extremely tiny lizards have been found, such as one named Sphaerodactylus parthenopion, which was discovered in the British Virgin Islands in 1965. These lizards are the smallest of 23,000 species of reptiles, birds, and mammals.

The discovery of S. ariasae was no accident. Researchers Blair Hedges of Pennsylvania State University in University Park and Richard Thomas of the University of Puerto Rico traveled to Beata specifically to look for new species.

"If you want to find something new to science, you need to get as far from civilization as possible," said Hedges, an evolutionary biologist. "That's what we do."

For example, in 1994, Blair flew over eastern Cuba to scout out areas he thought might harbor new species. "I saw this rugged area of a mountain range, with very course topography—extremely inaccessible—and knew that was where I wanted to search," said Blair. After landing and hiking to the spot he had identified from the airplane, he found a new species of lizard.

"Almost every trip we make turns up a new species. On one trip we found eight," said Blair. Together the scientists have discovered more than 50 new species of amphibians and reptiles in the Caribbean.

Not Easy to Find

The scientists loaded up 50 gallons of motor boat fuel onto a truck and drove to the coastal town of Cabo Rojo in the Dominican Republic, where they rented a 15-foot boat. But finding a fisherman willing to make the journey to Beata was difficult because the seas are rough and the journey takes several hours.

After arranging the transportation and reaching the island, Hedges and Thomas hiked and camped around the island for a few days before they came across the area where they found the new lizard.

According to Hedges, Beata was first discovered and named by Columbus about 500 years ago. Soon after its discovery, the island was pillaged for its lumber. Most of the original growth forest—the big tropical trees that originally covered the island—have been replaced by short scruffy trees no taller than 30 feet (9 meters), which cover the low-lying flat limestone land.

On their third day, at the entrance to a small and moist cave, the scientists first saw one of the tiny lizards skitter past.

The researchers got on their hands and knees and rooted through the dead leaves on the ground, watching carefully for movement as they waited to catch a specimen. The lizard has an adaptation that allows its tail to break off very easily—a clever escape tactic in case a predator nabs the creature by its tail. This feature, along with the lizard's small size, makes it particularly tricky to catch.

The researchers collected eight of the lizards for further study. The research is published in the Caribbean Journal of Science.

Not Endangered

Because its habitat is remote, S. ariasae is not currently endangered. But for many species of reptiles and amphibians that occupy specific habitats in the Caribbean forests, once the vegetation is gone, the fauna is likely to follow.

During an assessment of amphibians in the Caribbean commissioned by the World Conservation Union, Hedges found that of 170 amphibians, almost half were endangered. "Of these, only one is currently classified as endangered," he said. "I think I would probably get about the same numbers for reptiles."

Beata is part of the Jaragua National Park in the Dominican Republic. Although all its flora and fauna are protected, Hedges said the island is not adequately protected to prevent further illegal deforestation. "What I have seen raises a lot of red flags," he said.

Many species live in specific niches in small areas of forest. Once these forests are gone, the animals continue to live out their lives "like the living dead," but the environment doesn't support further generations, Hedges said.

In the Caribbean overall, barely 10 percent of the original forests still remain; Haiti has less than one percent.

"Things are changing very rapidly," said Hedges, adding: "The Caribbean will probably be one of the first biodiversity disasters."

Michael Smith of Conservation International expressed similar concerns about the future of flora and fauna in the region. "The Caribbean is one of the richest places on Earth in terms of unique species, but they are extremely threatened," he noted. "If the Caribbean continues to lose species at the current rate, then one of the world's most distinctive natural systems will be devastated in our lifetimes."

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