Sphaerodactylus ariasae, the Jaragua sphaero or dwarf gecko, is a very small Gekkonidae species in the Sphaerodactylus genus. It is one of the world's two smallest known reptiles (the other is the S. parthenopion, native to the British Virgin Islands). The Jaragua sphaero measures 16–18 mm from the snout to the base of the tail and can fit on a US 25-cent coin. Its range is believed to be limited to Jaragua National Park in the extreme southwest of the Dominican Republic and the nearby forested Beata Island.