Today´s featured bird with a weird beak is the double-toothed barbet (Lybius bidentatus), a colourful member of the African barbets, and around the size of a sparrow.
Double-toothed barbet (Lybius bidentatus) taxidermy specimen from the Zoological Insitute Tübingen
The origin of their name is quite obvious, as their upper beaks shows some pretty big pseudotooth-like projections.
Another photo showing the whole taxidermy specimen:
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