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Ruggero Morimando wrote:Species are actually artificial distinctions humans make to try to put an order in natural world and in the evolution/separations of living beings.
My question is the following: is it possible to have totally distinct "genetically determined" species, withouth even the smallest difference in exterior (fenotipical) appearance?
If the answer to this question is YES, the next thought of mine is that we have then to genetically analyze every specimen or at least every population to determine whether or not they belong to a different species...
Or my thought are simply absurd and meaningless...

My answer is YES (at least there might be some charecters easily overlooked). Werner MAYER called this the "individual species concept", so every specimen is its own species

Ruggero Morimando wrote:My question is the following: is it possible to have totally distinct "genetically determined" species, withouth even the smallest difference in exterior (fenotipical) appearance?
If the answer to this question is YES, the next thought of mine is that we have then to genetically analyze every specimen or at least every population to determine whether or not they belong to a different species...

Some years ago Ljljana Tomović (who is a real expert in V. ursinii and V. ammodytes) was firmly convinced
that V. ursinii graeca was not even a valid subspecies, let alone a species. She said (then), what people call
“V. ursinii graeca” is just the Greek population of V. ursinii macrops, nothing more than that...
Then she was forced to change her mind quite radically, and coauthored the famous paper (Ferchaud & al.
2012) promoting V. graeca as a species. It was a thorough change, but as a really honest scientist, she had
to admit that she had been terribly wrong for years. (A private conversation with Ljilja in Zagreb, October
2010.)
This might not be a direct answer to your question, but in a way it is.

Ruggero Morimando wrote:Species are actually artificial distinctions humans make to try to put an order in natural world and in the evolution/separations of living beings.

How very well said

I've noticed some are suggesting that this population might be a result of escaped captive snakes crossbreeding. Seems unlikely to me, but my knowledge is limited and I'd be curious to see if anyone here finds merit in the theory.

Just a quick reply before I gladly take part in the discussion again.

A bunch of us were in Walserland until yesterday. Much more to follow, but walser seems very much syntopic with aspis.

Well that's interesting, even syntopic. Do they use the same microclimate or it's like aspis is more in the rockyparts and walser more in the grassland beside the rocks? I know you spend to little time to say something , but maybe something ecological characteristics are obvious or guessable from the observations by the team.

Again, I'll get back to the discussion soon, but here this already.

viewtopic.php?f=14&t=2503

Joshua Smith wrote:I've noticed some are suggesting that this population might be a result of escaped captive snakes crossbreeding. Seems unlikely to me, but my knowledge is limited and I'd be curious to see if anyone here finds merit in the theory.

Possible crossbreeding with some captive snakes? But what could be more probable of an ancient crossbreeding with ”some” aspis specimens, if the two species live together, in tight contact, and in an isolated environment?
And we must also think that the phenotypic differences of walser from berus point exacty in the direction of an "aspis morph": more fragmented and discontinuous zig zag pattern on the dorsum, and more fragmented and numerous head scales. Could it be simply a case? Or the walser is actually related to ursinii and kaznakovii?
Some genetic analysis suggest this “species” is in fact more related to ursinii and other species, which are very distant as regards their range: but what does it mean “related”?
We can read in the pubblication: “The adder from Piemonte appears more closely related to the cluster regrouping V. dinniki, V. kaznakovi (from Georgia) and V. darevskii even if the bootstrap support is limited. It is thus likely that the split between V. ursinii, V. darevskii–V. kaznakovi and the adder from the Piemonte occurred during a similar period.”
Ok: the adder from Piemonte (V.walser) has arisen from a not better specified ancestor viper group “in the same period” of ursinii, darevskii and kaznakovii.
But “in the same period” also many other vipers and many other snakes had arisen in the world: this does not mean that V.walser is related to Trimeresurus (even if they probably share the most of their DNA, if it’s true that our DNA is at 98,5% identical to the one of the chimpanzees!)
And the authors, in fact, specify: “even if the bootstrap support is limited”.

This is my point of view: are we really 100% sure that DNA, alleles and so on are so trustworthy?
I fear a lot, for instance, to submit myself to a DNA analysis: I would not read in an issue that my alleles are more related to those of an Australopithecus than to the ones of Brad Pitt…
Yes, I admit I’m a bit skeptical about DNA… And, besides this, the phenotypic differences of the human beings in the world are much more relevant, I would say in a huge way, than those between berus and walser: but nobody thinks to analyse the DNA of a black man and compare it with the DNA of a man from Japan, and maybe split the human race…
But let’s go back to our vipers.
We read: “Additionally, two nuclear protein-coding loci (BTB and CNC homology 1 – BACH1; Townsend et al. 2008 and recombination activating gene 1 – RAG1; Townsend et al. 2004) were used to investigate the genetic variability within the nuclear genome. PCRs and sequencing were conducted with the same protocol as for the mtDNA, with, respectively, the 6primers F_Nik_Bach1 and R1_Bach1 (St€umpel 2012), and the primers Rag1_F1 and Rag1_R1 (St€umpel 2012), and the PCR amplification cycles following St€umpel (2012). For this aspect, four individuals were investigated: one individual from Piemonte and one sample each of the following species: V. berus, V. a. francisciredi and V. a. ammodytes.”
Four individuals... I’m not a statistician, but just 4 samples seem to me very few, to say the least…
But, I repeat, I’m not a statistician and I’m not a geneticist (even if I’m a medicine doctor). And so I cannot debate in the right way the problem or support what I feel, because I know and understand too little of alleles, DNA, mitochondria and reliability of the samples. This is impossible for me to say something more about the question, just as it’s impossible for me to say something about the neutrino, the quarks or the physics of the universe.
I can only admit, I’m not fully convinced of the importance of these genetic studies, particularly if they are born just to confirm the existence and the validity of a new “species”.
I only fear, with genes and DNA one could prove everything, and the contrary of everything.
Please take this post of mine just as a kind of joke or a provocating starting point for other thoughts and discussions!

@ Niklas:
* I only meant the harder characters of kaznakovi, not its coloration.
* My assumptions of niche segregation are surely less likely, after our little trip. But then again, macrops and bosniensis also co-exist... It is possible.

@ Ruggero:
* Of course, yes, the origin of species does not happen overnight, so there are cases where boundaries are less strong and/or still under construnction.
Not going into too much detail (because in part, I actually can't), species boundaries are related to reproductive isolation.
Reproductive isolation relates to lack of compatibility of DNA. While morphology has a genetic basis,
there is no guarantee that the fact that species/populations are not interfertile will reveal itself also in morphological characters visible to our eyes.
So, yes, of course, cryptic species exist.
* I'm not 100% sure, but I think a hybrid origin is unlikely, because of mtDNA being maternally inherited.
If species A crossbreeds with species B, the offspring will have mtDNA of A or B. Not a mix of both. On top of that it would be very coincidental if that mix would look like species C.
* I think you are misinterpreting the "the split between V. ursinii, V. darevskii–V. kaznakovi and the adder from the Piemonte".
They are saying that the split between the members of this group is unclear, not that these members may have split from anywhere in the phylogenetic tree (as you seem to say).
* Four individuals is not a lot, but I think some characters are so constant that one would even be enough.

Thanks Jeroen: I could reply on many points of your answer, but I'm writing with a smartphone and it's terrible.
Furthermore my opinions are not so important and I prefer to wait for others' opinions and thoughts.
One thing is clear anyway for all (authors included): everything is still far from being cleared!