Distribution from northern Colombia and in northern and western Venezuela and Trinidad. It is a Llanos ecosystem species. It occurs below 500m asl. In Trinidad it is widespread in coastal lowland areas, often sitting on emergent grass. Activity is crepuscular and nocturnal species of low altitude open environments of lowlands, including flooded grasslands, degraded areas with low vegetation, and shallow standing water. It breeds in standing water and swamps. Scarthyla vigilans is small SVL up to 21 mm; snout projecting beyond margin of lip; tympanum distinct, approximately half of eye diameter; hind limbs long; fingers unwebbed; toes nearly fully webbed; coloration in life, lime green at night, during the day pale brown with contrasting longitudinal stripes, or uniform dorsum; bones green in life and in recently preserved specimens. Most easily confused with Scinax all of which have reduced or completely lack webbing between first and second toes while toes one and two are fully webbed in Scarthyla. Faivovich et al. (2005) found a sister-group relationship between Scarthyla goinorum and pseudids (Lysapsus and Pseudis), and this group is nested within Hylinae.