Passerine
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A passerine is any bird of the order Passeriformes which includes more than half of all bird species. Sometimes known as perching birds, passerines generally have an anisodactyl arrangement of their toes, which facilitates perching.
Pterylosis or the feather tracts in a typical passerine
Male superb lyrebird (Menura novaehollandiae): This unique songbird shows strong sexual dimorphism, with a peculiarly apomorphic display of plumage in males.
Wieslochia fossil
Dactyly
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In biology, dactyly is the arrangement of digits on the hands, feet, or sometimes wings of a tetrapod animal. It comes from the Greek word δακτυλος = "finger".
Human foot with partial simple syndactyly.
Tridactyly (Mikhail Tal)
Didactyly
Monodactyly