QQuestion
Explain how the features of digits have changed in the course of evolution of horse.
✓Answer
In the earliest ancestor Eohippus, forelimbs had four functional toes and one splint, and hindlimbs had three toes with two splints; the third digit was very slender.
Through Mesohippus and Merychippus the lateral digits were gradually reduced and the third digit became longer and thicker, so that in Pliohippus and modern Equus only one stout third digit with two splints remains in each limb, adapted for fast running on hard ground.
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