In a fossil bed, you discover the preserved bones of a winged animal mixed in with the hones of small rodents. The small rodents are known from other fossils to have lived about two million years ago, but they are now extinct.
After considerable effort, you are able to collect and analyze DNA from the winged animal. You obtain the nucleotide sequence of the cytochrome c oxidase gene. When you compare this sequence to the sequence of the same gene in a bat, a rodent, a shrew, and a human, you find the following numbers of differences:
winged animal-bat -- 11 differences
winged animal-rodent -- 14 differences
winged animal-shrew -- 15 differences
winged animal-human -- 9 differences
What hypothesis does this data support?