Lowland Swamp Viper

Proatheris superciliaris is a small species that averages 40 to 50 cm (about 16 to 20 inches) in total length (body + tail), with a maximum total length of 61 cm (24 in). The females are slightly larger than the males. The head has a somewhat elongated appearance, the top of which is covered with small scales except for a pair of large supraocular scales, which are almost twice as long as they are wide.

It is found in East Africa. The southern part of its range begins near Beira, in central Mozambique, extends up north over the Mozambique Plain to Quissanga, and through Malawi and as far north as the floodplains of southern Tanzania at the northern end of Lake Malawi. The type locality given is "Terra Querimba" (= Quissanga mainland opposite Ilha Quirimba, Mozambique). Its range is apparently centered on the lower section of the Zambezi River and spreads out into the coastal plain of central Mozambique and the Shire Valley to Lake Chilwa and Malawi. However, other specimens have been found far from this region, such as in Cape Delgado Province, in north-eastern Mozambique, and Mwaya in south-western Tanzania.

One of the distinguishing characteristics of the Atheris group (to which Proatheris is closely related), is that they have prehensile tails. With Proatheris, the young and subadults have this capability, but it is diminished in the adults.