Skinks (Family Scincidae) are not only the most diverse reptile group but are also the world’s most species-rich family of terrestrial vertebrates. With ~1,660 described species, skinks have a global distribution, with diversity hotspots in Australasia, Asia, and Africa.
Skinks are characterised by having large shield-like head scales, smooth glossy cycloid scales (although some species have keeled scales), and a bony secondary palate.
Skinks epitomize diversity in virtually every aspect of their biology. Skinks can be terrestrial, arboreal, fossorial or semi-aquatic. They can inhabit deserts, rainforests, windswept oceanic islands, and alpine peaks.
Global skink distribution and diversity
Their body size exhibits a 21-fold difference from the smallest (24 mm snout-vent length [SVL], Scincella macrotis) to largest species (500 mm SVL, Acontias plumbeus).
Skinks exhibit the greatest degree of morphological variation of any lizard family, with species ranging from long and slender and large and robust. They exhibit extreme variation in limb development, from species with the full tetrapod complement of 4 long, 5-fingered limbs, to shorter limbs with fewer fingers, to species with either no forelimbs or (rarely) no hindlimbs, to forms lacking limbs altogether.
Skinks display more transitions from oviparity to viviparity than any other vertebrate (or invertebrate) family.
There are even two skink species that display geographic variation in their reproductive mode (& one species can even have both reproductive modes within the same clutch!!).