Multiple choice Which of the following is the earliest form of fossil in the phylogeny of horse? Eohippus Merychippus Equus Mesohippus Reveal answer Fill a bubble to check yourself A Correct answer Explanation The earliest form of fossil in the phylogeny of horse is Eohippus. The earliest horse had five-toed limbs whereas the present day or modern equus have one functional toe with a large hoof on each foot.