Little lizard

Natural History, Feb, 2002 by Kirsten L. Weir

A new species of lizard so small it can turn on a dime or stretch on a quarter--that's Sphaerodactylus ariasae, discovered on Beata Island (off the southwest coast of the Dominican Republic) by herpetologists S. Blair Hedges, of Pennsylvania State University, and Richard Thomas, of the University of Puerto Rico. Just over half an inch long from the tip of its snout to the base of its tail, the lizard ties its cousin S. parthenopion for the title of smallest amniote--a group that includes reptiles, mammals, and birds.

Island habitats are often home to "extreme" creatures, such as the smallest or largest of a kind. Many groups of organisms that successfully complete the voyage from the mainland to an island outpost evolve to fill niches left empty by taxonomic groups that didn't make the trip. Hedges and Thomas believe that S. ariasae may have adapted to occupy an ecological niche that is filled on the mainland by an invertebrate.

On Beata Island, the tiny gecko makes itself at home in moist leaf litter. No word on how many dimes it might come across in a day's slithering. ("At the Lower Size Limit in Amniote Vertebrates: A New Diminutive Lizard From the West Indies," Caribbean Journal of Science 37:4, 2001)