When Pennsylvania State University evolutionary biologist Blair Hedges is rooting around in dead leaves on his hands and knees, hunting for the tiniest animals alive, he grabs for any flash of movement he sees. Most recently, his labors earned him a dime-sized Caribbean geckothe world's smallest creature among reptiles, birds and mammals. "Being the smallest of 23,000 species," Hedges says, "it probably is close to the minimum size." A paper describing the lilliputian lizard is set to be published in December's issue of the Caribbean Journal of Science.

Hedges and a colleague found the animals, named Sphaerodactylus ariasae, in a sink hole and cave in a forest on the island of Beata, part of the Jaragua National Park in the Dominican Republic. The lizard, which stretches 16 millimetersabout three-quarters of an inchfrom nose to tail, shares the title of world's smallest with another reptile found in 1965 in the British Virgin Islands. The authors point out that extreme sized animals tend to be found on islands because they fill ecological niches left unexploited by other organisms that never made it to the island.

"[The find] shows us that we still know very little about the world's biodiversity, and especially areas that are very close to the United States," Hedges explains. Five years ago, he co-discovered the world's smallest four-legged creature, a 10 millimeter-long frog, in Cuba. "These new things are just turning up all the time in the Caribbean," Hedges notes. Unfortunately for that region, he says, "90 percent of the original forests are gone, and most of the world's biodiversity requires forests to survive." He recommends that conservancy agencies help third world countries enforce the boundaries of their national parks in order to stem the tide of potential extinction.