[2][3] The subspecific name, decosteri, is in honour of Belgian consul Juste De Coster, who collected natural history specimens at Delagoa Bay, Mozambique.

[3] The subspecific name, fitzsimonsi, is in honour of South African herpetologist Vivian Frederick Maynard FitzSimons.

[1][2] The preferred natural habitats of E. sundevallii are grassland, shrubland, savanna, and forest, at altitudes from sea level to 1,800 m (5,900 ft).

[1] Adults of E. sundevallii are slate-grey to black or dark brown on the upper body, with whitish to pinkish bellies.

Symptoms may include pain and swelling, nausea and vomiting, blurred vision, and loss of consciousness.