Lygodactylus williamsi, William's electric blue gecko, was first descovered by biologist William in the 1950's.
This small lizard species is confined to the Kimboza Forest in eastern Tanzania. This tropical forest habitat is rapidly shrinking due to deforestation.
Males are bright blue with a black throat and visible preanal pores and hemipenile bulges. The females are greenisch with a copperish shade and have almost no black on the throat, just a few stripes on the throat. Females can easily be confused with juvenile males that are also green, sometimes with a blueish cast. The adult snout-vent length is 5 to 8 cm.
This gecko eats small insects and drinks water from leaves. They are also fond of nectar.
This species is diurnal, an unusual behavior for a gecko in nature.