DNA Analysis Confirms African Forest Elephants Are A Distinct Species - Mongabay

[hatrack]

DNA evidence has shown that the forest elephant-Africa's smaller, shyer pachyderm-is indeed a separate species from the much more well-known savanna elephant. While scientists have long debated the status of the forest elephant (should it be considered a separate population, a subspecies, or a unique species?) a new study in the open-access journal PLoS Biology finds that genetically the forest elephant is unarguably a new species. If conservation authorities accept the new study, it will change elephant conservation efforts throughout Africa.

"The surprising finding is that forest and savanna elephants from Africa—which some have argued are the same species—are as distinct from each other as Asian elephants and mammoths," said co-author David Reich from the Department of Genetics at Harvard Medical School in a press release.

Professor Michi Hofreiter, who specializes in the study of ancient DNA in the Department of Biology at York, explains further: "The divergence of the two species took place around the time of the divergence of the Asian elephant and woolly mammoths. The split between African savanna and forest elephants is almost as old as the split between humans and chimpanzees. This result amazed us all."

Even in outside appearance Africa's forest and savanna elephant differ greatly. The savanna elephant is usually significantly larger than the forest: 3.5 meters shoulder height versus 2.5 meters and several tons heavier. In addition, the forest elephant's ears are rounder and its tusks straighter than its savanna cousins. "We now have to treat the forest and savanna elephants as two different units for conservation purposes," says Alfred Roca, assistant professor in the Department of Animal Sciences at the University of Illinois. "Since 1950, all African elephants have been conserved as one species. Now that we know the forest and savanna elephants are two very distinctive animals, the forest elephant should become a bigger priority for conservation purposes."

EDIT

http://news.mongabay.com/2011/0119-hance_elephants.html

[xchrom]

1. Fascinating. Nt

[Geoff R. Casavant]

2. Is there a universally accepted definition of "species?"

The definition I always assumed was that any given two organisms were of the same species if they could mate and produce a non-sterile offspring. It seems to me that whether forest and savanna elephants were the same species could have been answered a long time ago.

On the flip side, what is the minimum difference in DNA in order to differentiate species? Is there a bright line rule?

[guardian]

3. I had the same question.

I always thought the old rule of not being able to reproduce non-sterile offspring was the delineation. That's why a chihuahua and a great dane are the same species, but different breed.