Sarkidiornis is a genus within the family Anatidae. Sarkidiornis is sometimes considered a monotypic genus with its sole member the knob-billed duck (S. melanotos), a cosmopolitan species. Most taxonomic authorities, however, split the species into two:
| Image | Scientific name | Common name | Distribution |
|---|---|---|---|
| Sarkidiornis melanotos | Sub-Saharan Africa, Madagascar and Southern Asia from Pakistan to Laos and extreme southern China | ||
| Sarkidiornis sylvicola | eastern Paraguay, southeastern Brazil and extreme northeastern Argentina | ||