Figure 4. Bar chart showing the number of cetacean genera that have diagnostic type material described from each time interval for the entire world plus junior synonyms (unvetted genera, light blue), compared to the number of cetacean genera that have diagnostic type material described from each time interval for the entire world (vetted genera, dark blue). Note that both distributions are virtually identical. Correlation of the first differences displays a significant correlation (r² = 0.988).