Elephant Family Tree
The evolution of elephants can be pushed back as far as the Eocene, around 55 million years ago. However I'm only concerned with roughly their last 100,000 years of evolution.
The tree shows an early divergence of mastodon from mammoths with the African elephant evolving sometime between that split. Pygmy mammoths are shown to be closely related to Imperial mammoths. The divergence time was probably only a few thousand years from the time that the mammoth found themselves on the Channel Islands. Woolly mammoths are shown as a relatively late adaptation to the cold, Pleistocene climates. These mammoth are all shown to be on the lineage that led to the Indian elephant.