Slider Skinks (genus Lerista)
Lerista is a diverse (~ 80 species) genus of skinks endemic to Australia, commonly known as sliders. The genus is especially notable for the variation in the amount of limb reduction. The variation ranges from short-bodied forms with large legs bearing five toes, to elongate forms completely lacking legs. The body length of the lizards is 33–103 mm (1.3–4.1 in).
Their locomotion is linked to their body shape. The shorter skinks with prominent limbs travel on the surface; the longer skinks with reduced legs tend to burrow more. A phylogenetic tree of Lerista, derived from DNA analysis, reveals that limb loss has happened multiple times within this group. Limb loss has occurred relatively recently, in the past 3.6 million years or so.
(photos: Top 8 - L. macropisthopus - Bill and Mark Bell, B - Southeastern Slider, L. bougainvilli - Matt Clancy)