Digit (anatomy)

A digit is one of several most distal parts of a limb, such as fingers or toes, present in many vertebrates.

In other languages, e.g. Arabic, Russian, Polish, Spanish, Portuguese, Italian, Czech, Tagalog, Turkish, Bulgarian, and Persian, there are no specific one-word names for fingers and toes; these are called "digit of the hand" or "digit of the foot" instead.

[1] For instance the former chess world champion Mikhail Tal lived all his life with only three right-hand fingers.

[9] Thus, in the evolution of tetrapods a shift occurred where the outermost rays of the fins were lost and replaced by the inner radials, which evolve into the earliest digits.

Pre-existing distal radials in these modern fish develop in a very similar way to the digits of tetrapods.

[9][10] Several rows of digit-like distal fin radials are present in Tiktaalik, a much more complete Devonian vertebrate described in 2006.

Tiktaalik had some features of the forefin more similar to earlier fish, such as a large ulnare and a distinct axis of larger bones down the middle of the fin.

At any rate, it demonstrates that the fish–tetrapod transition was accompanied by significant character incongruence in functionally important structures."[9]p. 638.