The knob-billed duck (Sarkidiornis melanotos) or African comb duck is a type of duck found along the tropical/sub-tropical wetlands and waterways of Sub-Saharan Africa and the island of Madagascar, as well as most of South Asia and mainland Indochina.
Most taxonomic authorities classify the knob-billed duck and the comb duck separately. A misidentified species of extinct Mauritian comb duck was initially described from unrecognised remains of the Mauritius sheldgoose (Alopochen mauritiana); this was realised as early as 1897, but the printed case of mistaken identity can still, occasionally, be found in modern-day sources.
