Ruggero Morimando wrote:If I show you a new species and all the people can clearly see the markings/colors differences, the morphology of the animals, their distribution... the acceptance of this new species is automatic: not a “faith” but a "fact".
If a species is determined almost exclusively by DNA studies (which, in our case, are NOT 100% reliable), the acceptance of this new species is only (for most of us, except obviously for the authors of the study!) more or less a “belief” thing.
OK, I will start writing a paper about Vipera atra, a black species that lives together with Vipera aspis populations in the Alps. All the people will see the difference and say “fact”.
You keep saying “NOT 100% reliable” but that strikes me as a subjective notion. There IS morphological data and we can always cry out that we want more evidence, but then nothing ever gets resolved. Personally, I myself call for more evidence if restricted gene flow is likely and not looked into. While I am very curious about the existence of natural (sterile) walser x aspis hybrids, I don’t think much else is or has been going on.
Ruggero Morimando wrote: I think you make the question too easy in only 3 lines!
While I do appreciate this (after all, I asked for it, practically), I want to try to write a forum post, not an essay (although it’s hard to be brief, I admit, and I am certainly not very good at it).
I’ll try to be brief again. Probably will fail, though.
I am also mainly fascinated rather than fully up to speed with this, so I won’t bet my life on the validity of any species. But still..
1) The support of the branches that set it apart from aspis and berus is strong and the entire tree is in line with the evolutionary relationships between all involved species as understood today. Both your alleged hybrid parent species are far away from their alleged walser child and I cannot believe that a mixture of them would produce a Frankenstein that would pop up within an entirely different group.
2) If the nuclear markers are properly chosen, one animal per species can be enough.
3) There are plenty of sister taxa that are very far apart (even across oceans) and imho kaznakovi and walser ecology are fairly similar.
4) So what if walser lives together with aspis? The same goes for ursinii/aspis (France), ursinii/ammodytes (Greece), ursinii/bosniensis (Montenegro), ammodytes/xanthina (Greece), despite the text book cliché of niche segregation.
5) So what if walser has aspis-like traits? Look at the Vipera graeca example (and the understandable Tomovic response that Bero described). The entire Vipera berus “Alpine clade” also looks like aspis. Is that due to introgression? Is bosniensis flooded with aspis genes? Don’t let morphology and the limitations of our eye and urge to see what we know fool you…
6) Finally, I know it’s a lame argument which I have criticized myself in the past too, but I would have a hard time imagining Sylvain Ursenbacher authoring a piece that would omit such a radically different possibility. If only he, or maybe WW, could share their wisdom with us. In fact, I might ask Sylvain “can you rule out a hybrid origin?”…
I am usually fairly skeptical about poorly substantiated splits (no Emys trinacris, Bufotes variabilis, Salamandra longirostris, Stellagama, Hierophis carbonarius, Darevskia pontica, Zootoca carniolica for me (yet)), but this is just too strange not to be true, to put it bluntly. My understanding of the details is limited, but for now, I see absolutely no reason to reject it, I think the evidence suffices.
Voila! Not much more to add, I think, from my part. Or rather, already too much