SAN JUAN, Puerto Rico – U.S. scientists say they have identified 24 new species of lizards in the Caribbean whose ancestors immigrated to the region millions of years ago atop floating vegetation.
About half of the new species described are nearing extinction, and the other half are extinct and had been misclassified by several museums in the U.S. and Europe, said Blair Hedges, a biology professor at Penn State University who led the research team.
"They misclassified them, but it's not their fault. Very few people can set aside that amount of time in their life to look at skinks every day," he said in an interview Tuesday after the roughly five-year study whose findings were published this week in Zootaxa, a peer-review journal for animal taxonomists.
Skinks are a type of lizard found around the globe, and those in the Caribbean are among the few that have up to a one-year gestation period and produce a human-like placenta, he said. The new species were identified through various means, including comparing DNA and counting and analyzing their scales, he said.
Hedges said he has sent emails to museums including the Smithsonian Institution in Washington asking that they adjust the labels on jars and correct their files. A Smithsonian spokesman said no one was immediately available to comment.
As a result of the study, the new species described will be added to a global threatened species list, said Philip Bowles, who works with the International Union for Conservation of Nature, a Swiss-based nonprofit organization. The group is the oldest and largest of its kind, and the list it publishes is used by governments, nonprofits and others for conservation efforts.
The Caribbean lizards' biggest threat was and continues to be the mongoose, which was imported from India in the late 1800s to hunt rats scampering across the region's sugarcane fields, Hedges said. The lizard's lengthy gestation period also accelerated its demise, he added.
Gregory Mayer, a biology professor at the University of Wisconsin-Parkside who was not involved in the study, said he was surprised by Hedges' findings.
"It's certainly a lot of new species to be discovered at once," he said. "More than the description of 24 new species is the 13 new genera. That is certainly a lot more unusual and striking."
The study also mentions six currently recognized lizard species, including one in the British Virgin Islands that Mayer said he described about 12 years ago.
"I've been looking forward to this," Mayer said of the study, adding that he was curious to learn how Hedges and other scientists determined new species since the lizards' physical appearances are so similar. "It's a 245-page paper. It'll take a while to digest."
There is no organization or institution that monitors additions to the existing global list of species, but it is up to other scientists to validate or refute studies like the one Hedges published.
Mayer said the study was important because it could help save species apparently unique to islands like Dominica and Puerto Rico, when scientists previously thought such lizards lived elsewhere as well.
The study also points out that up to three different types of skinks lived in Jamaica, including one that climbed trees and another that burrowed in the ground. Most of the lizards described are brown, except for one species found in Anguilla that has a pastel blue tail.
The study does not estimate numbers for how many members of the threatened species remain.
"It's really hard to say for small animals," Hedges said. "When you have elephants and rhinos, you can count them."