New Italian Vipera

That´s the place to discuss on sytematics, distribution, etc.

Re: New Italian Vipera

Postby Ruggero M. » Wed Jul 06, 2016 3:43 pm

Thanks to Ilian, Jeroen and Gregoire!
I agree with all of you, and my opinions are only the opinions of a layman, who has studied yes, but not in particular these matters of taxonomy and evolution. So, in my posts, I simply think loud with myself! :D
Like Ilian, i'm not interested to know whether walser is a valid species, subspecies or a strange variation of berus... Probably it is a full species or a subspecies, ok, but... what does it mean actually, as stated by Ilian?
On the other side, I'm very curious about the possible origin of this "species" (why it is so and there, and from which ancestors has arisen and when), and the idea of Jeroen to ask directly one of the authors is obviously good and kind.
My thoughts about ancient hybridation with aspis were only thoughts, no more than that. The real question, till now unclear for all, is: where are the "roots" of this isolated viper?
Ruggero M.
 
Posts: 673
Joined: Tue May 13, 2014 7:15 pm
Hometown: Pavia
country: Italy

Re: New Italian Vipera

Postby Jeroen Speybroeck » Wed Jul 06, 2016 4:07 pm

@ Ilian:

Yes, there's a grey area around the concept of what a species is. Evolution is gradual and some lineages are still only on their way to become a nicely reproductively isolated species today, while others may even be getting back in touch with each other after having been separated for a while (on a geological time scale). Still, many cases are strong.

I'd rather have a proper molecular study than morphology only (while we of course need both). The fact that populations are clustered into species still means something to me - they are (more or less) reproductive isolated and share a common gene pool during their evolutionary history. DNA may not be as reliable as we would like, but these aspects are (often) more reliably document in genes than in external features.
Jeroen Speybroeck
Site Admin
 
Posts: 3161
Joined: Wed Nov 18, 2009 10:18 am
Hometown: Merelbeke
country: Belgium

Re: New Italian Vipera

Postby Ilian Velikov » Wed Jul 06, 2016 5:30 pm

Jeroen Speybroeck wrote: Evolution is gradual and some lineages are still only on their way to become a nicely reproductively isolated species today, while others may even be getting back in touch with each other after having been separated for a while (on a geological time scale).


Hasn't that been the case at any point in time throughout (evolutionary) history? Evolution is always in motion, so would that mean there's no such thing as "species"? Or should there be a "time frame" included in the definition of "species"?

Jeroen Speybroeck wrote:Still, many cases are strong.

I don't argue they are not strong and I can't give opinion about the methods used by scientist to prove those cases because I don't have the knowledge. What I meant is that all this research is done to prove something that we do not know the definition of...How does this work? How would you prove that a snake is 80cm long if you don't know what a centimeter is? That's what I'm trying to grasp.
Ilian Velikov
 
Posts: 1216
Joined: Thu May 21, 2009 12:19 pm
Hometown: Pravets
country: Bulgaria

Re: New Italian Vipera

Postby Berislav Horvatic » Wed Jul 06, 2016 10:13 pm

Ilian Velikov wrote: What I meant is that all this research is done to prove something that we do not Know
the definition of...How does this work? How would you prove that a snake is 80cm long
if you don't know what a centimeter is? That's what I'm trying to grasp.

Well, at present we have seven or so definitions of what a "species" is, which is still much better
than nothing at all. In any case, they are not so TERRIBLY different, as to make us utterly dispair...
There is still hope that biology might someday become a natural science sensu stricto (like physics,
or chemistry, or even geology,...) so let's have some patience. I mean you, a man young enough,
not me.
Berislav Horvatic
 
Posts: 1132
Joined: Wed Jun 03, 2009 4:35 pm
Hometown: Zagreb
country: Croatia

Re: New Italian Vipera

Postby Jeroen Speybroeck » Thu Jul 07, 2016 9:21 am

Berislav Horvatic wrote:In any case, they are not so TERRIBLY different, as to make us utterly dispair...

I guess, that's what I was trying to see, somehow, Ilian. Otherwise, you'd have to clarify what you mean with the species definition being lost. More precisely, I think Vipera walser is most likely a true species by any of the more commonly used definitions (but no one can ever be sure about anything as long as we haven't analysed the single last speciment of all living creatures, I guess...).

As to your timeframe: the usual schedule is speciation followed by extinction. There's not a single species on earth today that has been around forever. So, of course, if someone writes a fieldguide of herps of Europe, that book will not still be a very relevant thing to buy 10My from now. I guess we'd better tell our offspring not to count on the royalties too much then.

((Biology will probably never be as exact a science as Bero or anyone else would like. To my mind, it's about as ambitious a goal as to find the Holy Grail or figure out the meaning of life.))
Jeroen Speybroeck
Site Admin
 
Posts: 3161
Joined: Wed Nov 18, 2009 10:18 am
Hometown: Merelbeke
country: Belgium

Re: New Italian Vipera

Postby Ilian Velikov » Thu Jul 07, 2016 10:49 am

Berislav Horvatic wrote:In any case, they are not so TERRIBLY different, as to make us utterly dispair...


Jeroen Speybroeck wrote:I guess, that's what I was trying to see, somehow, Ilian.


Fair enough. I wasn't arguing, just looking for an explanation. As long as those definitions are "useful" in practice then it's fine.

Jeroen Speybroeck wrote:As to your timeframe: the usual schedule is speciation followed by extinction. There's not a single species on earth today that has been around forever. So, of course, if someone writes a fieldguide of herps of Europe, that book will not still be a very relevant thing to buy 10My from now. I guess we'd better tell our offspring not to count on the royalties too much then.


Obviously, but I didn't mean that. I was talking about those cases you mentioned where lineages are not yet reproductively isolated species and are in the middle of becoming separate species, sort of speak. And by timeframe in the definition I meant "Species is....this and this....that has remained genetically unchanged for...this and this...amount of time". Anyway, that was more of a rhetorical question as we can't put such exact limits.
Ilian Velikov
 
Posts: 1216
Joined: Thu May 21, 2009 12:19 pm
Hometown: Pravets
country: Bulgaria

Re: New Italian Vipera

Postby Jeroen Speybroeck » Thu Jul 07, 2016 11:34 am

Ilian Velikov wrote:
Jeroen Speybroeck wrote:As to your timeframe: the usual schedule is speciation followed by extinction. There's not a single species on earth today that has been around forever. So, of course, if someone writes a fieldguide of herps of Europe, that book will not still be a very relevant thing to buy 10My from now. I guess we'd better tell our offspring not to count on the royalties too much then.

Obviously, but I didn't mean that. I was talking about those cases you mentioned where lineages are not yet reproductively isolated species and are in the middle of becoming separate species, sort of speak. And by timeframe in the definition I meant "Species is....this and this....that has remained genetically unchanged for...this and this...amount of time". Anyway, that was more of a rhetorical question as we can't put such exact limits.

Well, yes, in some cases we can guess that some lineages are likely to evolve into true species by any definition but are not yet there. Those are the tough ones, because some would go ahead and already treat them as separate species and others wouldn't. There are cases like that in European herps (e.g. the use of the term "incipient species" for the Iberian wall lizard mess). I personally have come to terms with a certain level (note: vague!) of restricted gene flow instead of demanding 100% (note: not vague at all!) reproductive isolation, but it's never easy. Note that certain species concepts would go ahead calling each islet lizard population a different species as soon as they are the tiniest bit distinct, simply because they are unable to get in touch with their family elsewhere...

Note, that mutation and selection may cause the gene pool to change without any contact with other lineages/clades/populations, but I'm probably lecturing on something obvious again. ;)
Jeroen Speybroeck
Site Admin
 
Posts: 3161
Joined: Wed Nov 18, 2009 10:18 am
Hometown: Merelbeke
country: Belgium

Re: New Italian Vipera

Postby Ilian Velikov » Thu Jul 07, 2016 12:09 pm

Jeroen Speybroeck wrote:Note, that mutation and selection may cause the gene pool to change without any contact with other lineages/clades/populations, but I'm probably lecturing on something obvious again.


What's obvious for some might not be so for others, so just keep on lecturing, and don't be so sensitive (My "obviously" was regarding "not a single species has been around forever" and "a nowadays guide would not be relevant 10my from now", not regarding the whole lecture) ;)

Jeroen Speybroeck wrote:Note, that mutation and selection may cause the gene pool to change without any contact with other lineages/clades/populations


And as a prove to the point about "obvious" above:

Excuse me if my question is stupid or lame but in my mind the changes to the gene pool resulting from mutation and selection are what we call evolution. So is contact/hybridisation between species also considered evolution? Can we say that e.g. Pelophylax kl. esculentus evolved as a result of the contact between lessonae and ridibundus, or is there another more correct term?

And BTW...
Berislav Horvatic wrote:There is still hope that biology might someday become a natural science sensu stricto (like physics,
or chemistry, or even geology,...)


Jeroen Speybroeck wrote:((Biology will probably never be as exact a science as Bero or anyone else would like. To my mind, it's about as ambitious a goal as to find the Holy Grail or figure out the meaning of life.))


It's down to point of view I guess. To me physics and chemistry are no more "exact" than biology, it's just that we've agreed on more stuff when it comes to them. After all, science (no matter which one) is just a way for us to explain/translate things so that our senses could comprehend them. For all we know all our laws of physics might be completely wrong. There's no single exact universal truth, and the Universe is chaotic not in exact order like we wish to believe. So biology for me is as natural and exact as any science could be, but that's a different subject ;)
Ilian Velikov
 
Posts: 1216
Joined: Thu May 21, 2009 12:19 pm
Hometown: Pravets
country: Bulgaria

Re: New Italian Vipera

Postby Jeroen Speybroeck » Thu Jul 07, 2016 12:22 pm

I've been accused of many things but no one's ever called me sensitive. ;) :lol:
Don't worry, Ilian, I was not responding, but rather worried that nobody's still reading. I get that often because I (obviously) have difficult shutting up and then I think of people visiting this forum once every week and then they find this cascade of words without photos or field story...

Esculentus is a very special case, but secondary contact (in this case between two water frog taxa) is a fairly regular part of the process, yes, certainly in Europe. Esculentus is a weird example/exception of what may happen if reproductive isolation is not entire. Other examples are clonal all-female Darevskia 'species' resulting from ancient hybridisation.
Jeroen Speybroeck
Site Admin
 
Posts: 3161
Joined: Wed Nov 18, 2009 10:18 am
Hometown: Merelbeke
country: Belgium

Re: New Italian Vipera

Postby Ruggero M. » Thu Jul 07, 2016 12:22 pm

Please don't hate me... :lol:

What I write here now is not for criticize the work about V.walser, but to point out how many difficulties/traps the researchers can find doing a job like this. And the even bigger difficulties we laymen have to pass, to understand at least a little better the whole process behind such a work.

I personally do know very little about taxonomy and evolution, but I can understand that an ancient viper group, which was widespread in Europe thousands or millions of years ago, could gave origin to more species which now result completely isolated (walser) and very far from each other (walser and kaznakovi, for instance).
And, in fact, if there are "sister taxa" even across the oceans, this means the ancestors were the same before the continents separated.

I wanted now to underline another problem of these genetic studies, of whom I ignored the existence just few minutes ago: software.
Yes... I was reading the issue, trying to understand in a better way the meaning of p-distances and the reliability of genetics and trees, when I read another for me mysterious phrase.
The phrase was the following: "The genetic p-distances between the different species were generated with MEGA."

Stop. What the hell is MEGA? Surely an app, because scientists nowadays must rely on software to arrive to some conclusions.

And what have I found on the internet about MEGA as one of my first search results?
This: https://www.researchgate.net/post/Why_i ... logenetics

”That said, I also don't rely on MEGA5 for publishable phylogenetics work.”

“As many people have said here, MEGA is not very good for inferring phylogenies or more precisely, 'publishable phylogenies'. But MEGA is very helpful at initial stages of your data analysis. I think the alignment of the sequences is mostly done in MEGA, I do it.
Then you can build trees, infer TV/TS ratios, calculate genetic distances, etc.. there are lot more stuff you can do with MEGA. But that's it, you cannot use this analysis for publication, some journals might accept it, but most of them don't.”


I must admit many other people write MEGA is trusthworthy and good, and I do not want to say the work about walser has less value because they used MEGA and not another software.
My reflections here want to regain my post about "trust" and "belief".
There are so many error possibilities (even if it does not mean errors are necessarily present), possible traps and problems, that is sometimes very diffucult for us, who work in other sectors than genetics, to accept "at first glance" the creation of a new species with the help of DNA. And difficulties for the researchers to "defend" their pubblications and credibility against "attacks" of other experts and laymen.

That said, I sincerely hope (and I think at least with little reserve this) that walser is a true endemic and rare species of my Country and that its existence will help us to protect its valleys and its environment (which, I've seen, is also rich of smooth snakes which I like more than vipers!). :lol:
Ruggero M.
 
Posts: 673
Joined: Tue May 13, 2014 7:15 pm
Hometown: Pavia
country: Italy

PreviousNext

Return to Theoretical Section

Who is online

Users browsing this forum: No registered users and 5 guests