Knob Billed Male Duck: (Sarkidiornis melanotos) or African comb duck or comb duck is a type of duck.The male is much larger than the female, and has a large black knob on the Knob billed Duck (Sarkidiornis Melanotos) Commonly Found in Sub Saharan Africa and South Asia Stock Image Image of biodiversity, behavior: 326401309 Portrait Knob billed Duck Sarkidiornis Melanotos Bird Stock Photo 1460255972 Shutterstock Knob billed Duck The Knob billed Ducks in Songkhla Zongzhuang Birding