Did they max out their possible genetic variations a while back?
This prehistoric cat, Panthera blytheae, dates from 4.10 and 5.95 million years ago:
DNA evidence suggests that the so-called “big cats” — the Pantherinae subfamily, including lions, jaguars, tigers, leopards, snow leopards, and clouded leopards — diverged from their nearest evolutionary cousins, Felinae (which includes cougars, lynxes, and domestic cats), about 6.37 million years ago. However, the oldest fossils of big cats previously found are tooth fragments uncovered at Laetoli in Tanzania (the famed hominin site excavated by Mary Leakey in the 1970s), dating to just 3.6 million years ago.
Using magnetostratigraphy — dating fossils based on the distinctive patterns of reversals in Earth’s magnetic field, which are recorded in layers of rock — Tseng and his team were able to estimate the age of the skull at between 4.10 and 5.95 million years old.
Assuming there isn’t some kind of dating or imaging mistake, surely this is another example of stasis.
If we met that 4-6 million-year-old beast in the grasslands today, we might think it was just another big cat (and scream and throw things):
File under: Earlier than thought (and order a bigger cabinet,will you, Schmiddle?)
Note: The title formerly read “species”; fact is, most species look pretty feline in the details.