To find the unit rate of discovery, we need to determine how many species were discovered per year. If 4,000 new species of Myron animals were discovered in the last 2 years, we can calculate the unit rate as follows:
\[ \text{Unit Rate} = \frac{\text{Total Species Discovered}}{\text{Number of Years}} \]
Substituting the given values:
\[ \text{Unit Rate} = \frac{4,000 \text{ species}}{2 \text{ years}} = 2,000 \text{ species per year} \]
So, the unit rate of discovery is 2,000 species per year.