Which of the following is referred to be the first one toed horse?

Options

A. Eqqus
B. Eohippus
C. Merychippus
D. Pliohippus

Answer

To determine which of the following is referred to as the first one-toed horse, we need to analyze the evolutionary history of horses. Here’s a step-by-step breakdown of the solution:

### Step 1: Understand the Evolutionary Timeline
- The evolution of horses can be traced back through several genera. The primitive horse is known as **Eohippus**.

### Step 2: Identify the Genera in Order
- The order of evolution is as follows:
1. **Eohippus** (the earliest horse)
2. **Mesohippus**
3. **Merichippus**
4. **Pliohippus**
5. **Equus** (the modern horse)

### Step 3: Analyze the Number of Toes
- Eohippus had **three toes**.
- Mesohippus also had **three toes**.
- Merichippus had **two toes**.
- **Pliohippus** is significant because it is the first horse to have **one toe**.
- Equus, the modern horse, also has **one toe**.

### Step 4: Conclusion
- Based on the evolutionary history and the number of toes, the first one-toed horse is identified as **Pliohippus**.

### Final Answer
- The first one-toed horse is **Pliohippus**.

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