The oldest fossil of modern horse is known as

Options

A. Eohippus
B. Mesohippus
C. Merychippus
D. Equus

Answer

**Step-by-Step Solution:**

1. **Understand the Question**: The question asks for the oldest fossil of the modern horse.

2. **Identify Key Terms**: Focus on the term "modern horse" which refers to the species that we recognize today.

3. **Review Evolutionary History**: The evolutionary history of horses includes several key species:
- **Eohippus**: This is the earliest known ancestor of the modern horse, which lived around 55 million years ago. It was small, about the size of a fox.
- **Mesohippus**: Evolved from Eohippus, around 40 million years ago.
- **Merychippus**: Evolved from Mesohippus, around 20 million years ago.
- **Hipparion**: Another ancestor that appeared later.
- **Equus**: This is the genus that includes modern horses, which evolved around 4 to 5 million years ago.

4. **Determine the Answer**: Since the question specifically asks for the oldest fossil of the modern horse, we identify that the oldest ancestor leading to modern horses is the **Eohippus**.

5. **Conclude**: Thus, the answer to the question is that the oldest fossil of the modern horse is known as **Eohippus**.

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