Pachydactylus
Pachydactylus is a genus of insectivorous geckos, lizards in the family Gekkonidae. The genus is endemic to Africa, and member species are commonly known as thick-toed geckos. The genus also displays rich speciation, having 57 distinct species identified when compared to other closely related gecko genera like "Rhoptropus," most of which have emerged since 35Ma. It has been suggested that the reason for this rich speciation not from adaptive radiation nor nonadaptive radiation, but that the genus represents a clade somewhere between the two drivers of speciation. "P. bibronii" geckos have been used by NASA as animal models  for experimentation. Description. The genus "Pachydactylus" is characterized by dilated toe tips, usually with undivided scansors. Body scales are small, granular and non-overlapping, with scattered, large keeled tubercles. Coloration of Pachydactylus species varies, but is generally drab in color. Presence of adhesive toe pads varies by species and habitat, with rock dwelling species of "Pachydactylus" retaining adhesive pads, but unambiguous independent loss of toe pads in sand dwelling and burrowing species like "P. rangei". Body size in "Pachydactylus" varies across the 57 species, ranging from 35 to 115mm Snout-Vent Length (SVL) with the ancestral condition of a  larger body size with adhesive toe pads to suit a generalist habitat. Behavior. All observed species of "Pachydactylus" are strictly nocturnal. Habitat. "Pachydactylus" species live in a diverse range of habitats across Southern Africa. Habitat varies by species, with some species preferring generalist habitats, human dwellings, rock-dwellings, and sand dwellings. Habitat preference typically varies by body size and retention of toe pads, which varies across the genus. The body size of "Pachydactylus" geckos has been shown to correlate with their habitat range. Diet. Lizards of the genus "Pachydactylus" feed mainly on arthropods, but have been observed eating small vertebrates . Geographic range. The geographic range of the genus "Pachydactylus" is centered on Southern Africa, with some species reaching East Africa, the northernmost limit of their distribution. In South Africa's rugged Richtersveld region, "Pachydactylus" geckos comprised 13 of 18 all gecko species surveyed. Species. There are 57 species that are recognized as being valid: "Nota bene": A binomial authority in parentheses indicates that the species was originally described in a genus other than "Pachydactylus".