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 Post subject: 2 Different species of African Elephants???
Unread postPosted: Wed Dec 22, 2010 10:31 am 
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The African elephant as we know it has been reclassified as 2 different species.

Up till now it has been believed that the African Bush Elephant and the African Savannah Elephant were one and the same species and it was only due to their totally different habitat that they look so different.

Researchers in York have established, through their DNA pattern, that it is in fact 2 totally different species. They are just as different as an Indian Elephant and a Woolly Mammoth.

So we have in fact the 2 biggest land based Mammals on the Earth. :dance: :big_eyes:


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 Post subject: Re: 2 Different species of African Elephants???
Unread postPosted: Wed Dec 22, 2010 10:45 am 
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Michel, has that now been officially done? Names? Species or subspecies? I do know that I've read of this before. And wasn't there even talk of splitting off another (sub?)species, somewhere in West Africa? Or am I confused with this one now?

Do you have a source where one can read more?

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 Post subject: Re: 2 Different species of African Elephants???
Unread postPosted: Wed Dec 22, 2010 10:51 am 
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Thank you Michel , that is very interesting :thumbs_up: You are of course talking of the elephant occuring in the forests of Zaire which is somewhat smaller than the savannah ellephant :hmz:

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 Post subject: Re: 2 Different species of African Elephants???
Unread postPosted: Wed Dec 22, 2010 11:04 am 
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We might be looking at getting a classification like this:

Savannah Elephant

Kingdom: Animalia
Phylum: Chordata
Class: Mammalia
Order: Proboscidea
Family: Elephantidae
Genus: Loxodonta
Species: L. africana


Bush/ Forest Elephant

Kingdom: Animalia
Phylum: Chordata
Class: Mammalia
Order: Proboscidea
Family: Elephantidae
Genus: Loxodonta
Species: L. cyclotis

But that is just my thinking process.
Let's just wait and see what the intellectuals have to say about it. :lol:


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 Post subject: Re: 2 Different species of African Elephants???
Unread postPosted: Wed Dec 22, 2010 11:06 am 
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Heres a piece from nature, they list two soirces so im going to try and get a hold of them, interesting stuff :thumbs_up:
Quote:
African elephants are two distinct species
Genomic analysis shows split happened much earlier than previously thought.

Natasha Gilbert


A tussle over whether African elephants are one species or two has been settled by DNA analysis.Gerry Ellis/Minden Pictures/FLPA RM
African forest-dwelling elephants (Loxodonta cyclotis) are a separate species from those living in the African savanna (Loxodonta africana), researchers have shown.

Scientists have long debated whether African elephants belong to the same or different species. They look very different, with the savanna elephant weighing around 7 tonnes — roughly double the weight of the forest elephant. But studies had suggested they were the same species — DNA in mitochondria (the cell's energy factories) from African elephants found evidence of interbreeding between forest and savanna elephants around 500,000 years ago2.

Now a group of scientists have taken a deeper look at the African elephants' genetic ancestry. The researchers sequenced the nuclear genomes of both types of African elephant, as well as that of the Asian elephant (Elephas maximus). They also extracted and sequenced DNA from the extinct woolly mammoth (Mammuthus primigenius) and mastodon (Mammut americanum) — ancient elephant ancestors. By comparing all these genomes, the team found that the forest and savanna elephants diverged into separate species between 2.6 and 5.6 million years ago. The study is published online in the journal Plos Biology1.

"They split about the same time as African and Asian elephants split into separate species, and much longer ago than people previously thought," says David Reich, a population geneticist at Harvard Medical School in Boston, Massachusetts, and a lead author on the study.

"You can no more call African elephants the same species as you can Asian elephants and the mammoth," he adds.

Conservation consequences

Most researchers agree that the Asian elephant and the mammoth are separate species, says Thomas Gilbert, a geneticist at the University of Copenhagen. "But this study really hammers the coffin shut on any arguments that the forest and savannah are anything but different species, or even genera," he says.

Mitochondrial DNA can only give researchers information on maternal ancestry, as this genetic material is inherited solely from the mother. Examining the nuclear genome, which is around 200,000 times larger than that contained in mitochondria, gives a broader and more accurate picture of elephants' history. "You get a different picture by looking at nuclear DNA", says Reich.

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Mitochondrial DNA evidence suggesting that forest and savanna elephants interbred recently and had a recent shared female ancestor can be explained as a result of the female elephant's social behaviour, the researchers say. Females tend to stay close to their place of birth, while the males roam. Herds of female forest elephants could have repeatedly come into contact and bred with migrating male savanna elephants. Over a long period of time, the forest elephant gene pool would become diluted and displaced by that of the savanna elephants, but the forest DNA would be conserved in the mitochondrial DNA, which is passed on through the female line.

"What we see is an ancient split with a bit of gene flow more recently," he says. Hybridization happens between closely related animals and does not necessarily imply that the two are the same species, he says.

The authors suggest that the findings will help to reprioritize elephant conservation programmes. All African elephants are currently conserved as the same species. But the evidence that they are two distinct species suggests that they may be facing different pressures and require different conservation strategies. The forest elephants should become a greater conservation priority, the study says.

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 Post subject: Re: 2 Different species of African Elephants???
Unread postPosted: Wed Dec 22, 2010 11:09 am 
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Great.

Thanks Odessy. :thumbs_up:

Very interesting stuff. :shock:


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 Post subject: Re: 2 Different species of African Elephants???
Unread postPosted: Wed Dec 22, 2010 11:13 am 
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Here's the paper and most looks like it is visible without having to have an account

Genomic DNA sequences from mastodon and wooly mammoth reveal deep speciation of forest and savanna elephants

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 Post subject: Re: 2 Different species of African Elephants???
Unread postPosted: Wed Dec 22, 2010 11:35 am 
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Years back a group of researchers were in Kenya studying the difference between the elephants found in the plains (Amboseli, Masai Mara and so on) and the ones found the forests (Aberdares, Mount Kenya).
They then concluded that they were two distinct species and each had adapted itself in different ways and according to the environment. Forest elephants were a lot smaller, with smaller tusks and also had a difference in the trunk, something to do with the kind of vegetation each species fed on and ways of reaching it.

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 Post subject: Re: 2 Different species of African Elephants???
Unread postPosted: Wed Dec 22, 2010 12:26 pm 
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True, but that difference was due to their totally different habitats.
Still they were not seen as 2 different species.
Not even different sub- species.

Now they seem to have found the fundamental difference between those 2 in the DNA. :thumbs_up:


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 Post subject: Re: 2 Different species of African Elephants???
Unread postPosted: Sat Dec 25, 2010 3:48 pm 
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Wow
This is totally out of the blue for me I always thought it was o e type of elephant. So are both of these elephant found in kruger. How do you te the difference.

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 Post subject: Re: 2 Different species of African Elephants???
Unread postPosted: Sat Dec 25, 2010 4:07 pm 
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The dabeaate is old: In 2001 scientists described molecular evidence showing that forest- and savanna-dwelling elephants, would merit their own species name. I am curious to know if a new taxonomy will be established.
BTW: Who decides that African savanna and forest elephants should be classified as two distinct species?


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 Post subject: Re: 2 Different species of African Elephants???
Unread postPosted: Sat Dec 25, 2010 11:35 pm 
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The distinction whether they are two species or just two-sub species used to lie in the ability to breed.

When sub-species mate they will be able to breed successfully, producing fertile young.

When two animals of different species mate, they will either not be able to mate, they will not be able to produce young, or as in the case of donkeys and horses they will produce infertile young (mules).

I wonder whether this definition is still accepted in the age of DNA and genetics?

So this brings me to the question whether the savanna elephant and the forest elephant will be able to successfully produce fertile young?

There are pertinent structural differences visible to the eye between these two species. This has now indeed been confirmed by genetics. But I haven't seen the question of breeding addressed in any of the articles I have read on this? This one quoted in this thread seems to suggest that they may in fact interbreed and that this can threaten the integrity of the forest elephant gene pool.

Are they then in fact really separate species? :hmz:

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 Post subject: Re: 2 Different species of African Elephants???
Unread postPosted: Sun Dec 26, 2010 12:44 am 
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Imberbe wrote:
So this brings me to the question whether the savanna elephant and the forest elephant will be able to successfully produce fertile young?


According to the paper: yes

Quote:
If forest elephant female herds experienced repeated waves of migration from dominant savanna bulls, displacing more and more of the nuclear gene pool in each wave, this could explain why today there are some savanna herds that have mtDNA that is characteristic of forest elephants but little or no trace of forest DNA in the nuclear genome

http://www.plosbiology.org/article/info ... io.1000564" onclick="window.open(this.href);return false;


Brian Handwerk, for National Geographic News, Published December 22, 2010

explains:

Quote:
Interspecies Elephant Sex?

Debate over the species status of African elephants has been simmering for at least a decade.

A 2001 study in the journal Science included the first DNA evidence that the savanna and forest elephants are separate species.

But then other studies showed that at least a small number of savanna elephants shared mitochondrial DNA—genetic information passed down from only mothers—with forest elephants.

This "proved there was some interbreeding within at least the past 500,000 years," Reich explained.

But that limited interbreeding isn't evidence that the two elephant types are from the same species, he said. It's just an example of interspecies hybridization, relatively common in the animal world, ha added.


http://news.nationalgeographic.com/news ... w-science/" onclick="window.open(this.href);return false;


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 Post subject: Re: 2 Different species of African Elephants???
Unread postPosted: Sun Dec 26, 2010 8:09 am 
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Good Point Imberbe :thumbs_up:

Toko's link from National geographic sort of refers to the fact that these can be classified as different species even if they are able to produce fertile young and that is true as far as I understand it. A species is a taxonomic unit, a biologically relevant one but still a TU and often a subjective one at that.

Species are defined by what are known as species concepts, which work in defining some or other discontinuity in the traits of organisms, so basically how different two populations of organisms must be in order to be classed as two separate species. I know of 8 different species concepts and although it is difficult to see where each is applied taxonomists use these to classify organisms and this study is a perfect example of taxonomists trying to determine which species concept (SC) is most appropriate.

Imberbe explained how separate species can be classified by the ability to produce fertile offspring. That is the biological species concept and is used quite often. Basically here a species is a group of organisms potentially or actually reproductively isolated from another group of organisms by pre or post mating mechanisms . This includes hybrid viability (post) and sexual isolation(pre, sperm characteristics etc). Until recently it was the most widely accepted.

There are 7 other species concepts such as the morphological and phenetic SC's. These two are similar in that they both distinguish species based on morphological characteristics, so each species is morphologically distinct from its closest relative and this is based on a type specimen which is the first to be found of that species and described (its best to collect one from the edge of its known distribution). The phentic SC is different from the morphological SC only in that it confers some exact degree of morphological difference using a phenetic distance statistic .

Then you also get the evolutionary, Ecological, phylogenetic cohesion and recognition species concepts. in the evolutionary SC a species is seen as an independent evolutionary lineage with actual reproductive isolation. So in that SC any population that is sufficiently isolated genetically or biogeographically could be considered a separate species and is the one I think has been used in these studies.
The ecological SC defines a species as a group of organisms exploiting the same environmental niche. Here if two very different organisms interbreed the hybrid in theory would be maladapted because it has genes that are not co-adapted to exploit a particular resource.

The phylogenetic SC defines species as a group of organisms in which all individuals share unique derived characteristics which are not present in their relatives. This does use morphological characteristics of the organisms but the derived characters (apomorphs) can be identified genetically so this is quite a powerful one.

ok some of these are not as easy to understand as the rest and the cohesion species concept, which is the newest one as far as I know is very, very difficult. Im pretty sure I do not quite understand it. It refers to a species as the most inclusive group of organisms having the potential for phenotypic cohesion (physical appearance) through demographic or genetic exchange abilities. It involves tons of other theory but I dont think its necessary to explain here.

The last SC and one of my favourite is the recognition species concept. Here a species is a population which shares the same specific mate recognition system (SMRS). an SMRS included calls, behaviours, appearance and a suite of other components used to choose a mate. This concept is conceptually much better than the biological SC because it does not rely on mating to define a species and every species can be defined based on a unique SMRS.

So taxonomy is a very interesting but frustrating field of science as how to define a species is not cast in stone and often a suite of SC's are used to classify organisms. The simplest, which is the morphological species concept is used often by all of us in field guides and we all know about the biological (or at least the idea of it) SC. So really it is subjective and is most effected by the scale at which the species is examined.So the savanna and forest elephant can easily be classified as separate species using a number of the concepts and as the same species by others.

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 Post subject: Re: 2 Different species of African Elephants???
Unread postPosted: Sun Dec 26, 2010 9:42 am 
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oddesy wrote:
Scips they already completed the study which means that they were successful in getting the grant, and so called scientists :hmz: could you have done better?


Just joking there bud, but, the studies and the fact that L. Cyclotis is a totally different species was mentioned many years ago already, also there was/is talk of yet another species(West African elephant) for many years in scientific circles. :wink:

IMHO, the evolution of these ellies and the Desert Elephant(Also with some distinct differentials) did happen for them to adapt to the habitat. (Also see Knysna Ellies and their feeding habits etc.) :thumbs_up: And as you rightly mentioned, so many methods that disprove each other in so many ways, and the newest news is done with a fairly new scientific analysis. 8)

What is interesting is that the forest dwelling elephant(L. Cyclotis) was more highly rated than L. Africana for it's ivory, also by poachers. And there were cries to actually have them classed as a different specie, and not a Sub-specie as far as the 90's. That will then move them from "Threatened" to "Endangered", ensuring the continious protection from all protection bodies world wide. :thumbs_up:

And believe me, I am all for their protection, I just feel that the science in question is not totally infallable. :hmz:

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