Which one of the following is reptilian ancestor of birds ?

Options

A. Hesperornis
B. Ichthyornis
C. Archaeopteryx
D. Lychaenops.

Answer

To answer the question "Which one of the following is the reptilian ancestor of birds?", we can follow these steps:

### Step-by-Step Solution:

1. **Understanding the Question**: The question asks for the reptilian ancestor of birds, which implies we need to identify a specific species or genus that is recognized as a precursor to modern birds.

2. **Identifying Relevant Fossils**: The first step in identifying the reptilian ancestor is to look at fossil evidence. The question hints that fossils from the Jurassic period are significant in this context.

3. **Recognizing Key Genera**: Two genera are mentioned in the video transcript: **Archaeopteryx** and **Archaeorhynchus**. These genera are crucial in understanding the evolutionary link between reptiles and birds.

4. **Characteristics of Archaeopteryx**:
- **Size**: Archaeopteryx was approximately the size of a crow.
- **Physical Features**: It possessed feathers and wings, which are characteristics of birds. However, it also had a long tail and a toothy beak, which are more reptilian features.

5. **Conclusion**: Based on the fossil evidence and the characteristics mentioned, **Archaeopteryx** is identified as the reptilian ancestor of birds.

### Final Answer:
The reptilian ancestor of birds is **Archaeopteryx**.

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