Complex sentence: It confirmed that the quagga was more closely related to zebras than to horses, with the quagga and mountain zebra ("Equus zebra") sharing an ancestor 3--4 million years ago.
Split into simpler sentences: It confirmed that the quagga was more closely related to zebras than to horses. It also found that the quagga and mountain zebra ("Equus zebra") shared an ancestor 3--4 million years ago.