The
Virgin Islands dwarf sphaero or
Virgin Islands dwarf gecko (
Sphaerodactylus parthenopion) is a species of
gecko and also one of the
smallest terrestrial vertebrates. It has only been found on three of the
British Virgin Islands:
Virgin Gorda,
Tortola, and
Moskito Island (also spelled "Mosquito Island"). It was discovered in 1964 and is suspected to be a close relative of
Sphaerodactylus nicholsi, a
dwarf sphaero from the nearby island of
Puerto Rico. It shares its range with the
big-scaled least gecko (
S. macrolepis), which is found in leaf litter. Unlike this larger gecko, the Virgin Islands dwarf sphaero lives on drier hillsides, yet prefers moist
microhabitats found under rocks because it lacks the
adaptations necessary for preventing water loss, which is a significant problem due to its small body size.