Karpathos Winter-Snake ??

[Ilias Strachinis]

p.s.#2 I found this one from Leros : http://www.mrtso.com/2010/05/leros-first-rides/ (scroll down)
It's not such a good photo but to me this is not a caspius...

[Mario Schweiger]

very hard to say.
All these Dolichophis, Hierophis may have very very strange youth pattern.
Look at this H. gemonensis from Montenegro

HierGemo.jpg (148.33 KiB) Viewed 5019 times

Btw, cant await to have a nice day/evening/dinner in Greece (photo from link above) again

Mario

[Ilias Strachinis]

On Leros island it is D. jugularis
PDF-2063 in DB

Mario

now this makes it even stranger..

[Matt Wilson]

The photo from Leros looks like a young jugularis to me, but it is bizarre that on Kos caspius and jugularis occur together (the only Greek island where they do), but on Nissyros there is caspius and no jugularis, and the same on Kalimnos, the two islands nearest to Kos. Weird, but that's how it is

[Ilias Strachinis]

now tell me this distribution isn't weird!

jugcas.jpg (70.44 KiB) Viewed 4994 times

[Jeroen Speybroeck]

Things are never simple in biology, which causes a lot of trouble to the rational minds of men.

4 thoughts.

(1) In addition to Mario's excellent gemonensis example, I think we need to be careful about our faith in external features, especially colouration of closely related species with a lot of variability. This might cause overlap and/or parallelism in phenotypic expression, right? As I already said to Ilias off the forum, I believe we should in some cases accept that we cannot attribute every animal to a species, especially since the molecular revolution. If you don't buy this, let me know when you're ready for your blind test on Speleomantes .

(2) Whether species colonise an island and/or persist, is a process which involves chance. Either or both can - accidently - reach an island directly or indirectly at different moments in time. If they are indeed two valid species, competitive exclusion is likely to result in one of both remaining as a result of niche similarity (with Kos being the exception, if indeed both species live there). For me, this, by itself, can be enough reason to explain island distributions that don't really cluster like you would expect or (worse) like.

(3) A role is certainly played by sea trenches as a proxy for past biogeographical barriers. There are parts of the sea between Karpathos and Rhodos, as well as between Karpathos and Crete, which are over 1000m in depth. While this will not explain the entire observed distribution of the two species by itself, it might explain the Karpathos case as the result of an old colonisation followed by.

(4) Maybe someone will come up with some evidence that there's no reproductive isolation between both taxa and lump them back into a single species?
( I don't know the original species split evidence by heart. Mario, would that be Schätti & Wilson 1986? Or Schätti 1988? )

I'm sure this is all stuff you all already know, but indulge me for sorting out my thoughts in public

[Matt Wilson]

If they are indeed two valid species, competitive exclusion is likely to result in one of both remaining as a result of niche similarity (with Kos being the exception, if indeed both species live there).

Jeroen, I assure you they both do, if you want proof I will email the photos of two Dolichophis caspius I found there, one of 180cm and another of 220cm (largest snake I have seen in Europe I think), but the niche of a common Colubrid is filled by jugularis on that island as it is far more common than caspius. This raises another point in helping to define these 'species', jugularis in Greece does not seem to grow very large (although in the Middle East they surely do!), and as far as I know, has never exceeded 2 metres on a Greek island, in fact I am not aware of any recorded jugularis in Greece that exceeds 170-80cm. Whereas caspius frequently does on the Aegean islands, as I have seen and sure you have too Jeroen. Does that go anywhere towards defining these two species? Or is it all owing to DNA? As you know, I'm no scientist....

[Jeroen Speybroeck]

No doubt, Matt! I remember http://www.euroherp.com/Field/kos1.php
That's about as typical a caspius as well as a jugularis anyone could find.

I only added that as a minor side note, in the spirit of my (1). In other words, IF(!) we would be erroneously assuming certain features to be conclusive for IDing. Merely meant as a hypothesis, which I do not rule out for the full 100% (although rather with subadult specimens, unlike Matt's from Kos), because there are e.g. no pholidosis or other scalation features allowing a certain distinction between the two.

Maybe I'm being confusing, including to myself

To sum it up, I believe (a) that Kos is indeed an exception to the rule, and (b) that nature is full of those. You could also consider the overlap of viridiflavus and gemonensis in Istria such an exception more or less. BUT in reality, these are NO true exceptions, of course, because there IS in fact a part of the species's niches which does NOT overlap.

I'm sure someone has a theory of competitive exclusion and niche seggregation of these 2 species on the mainland, which might among other things relate to adult size (as (local) cause or consequence). Mario, any idea?

I'm sure, Matt, you will agree that your impressions are but that, since they are based on a limited sample size. In fact reminds me of Bero's reasoning concerning the size of Arctic vipers...

( P.S.: Kos is not Europe )

[Jeroen Speybroeck]

your impressions are but that

Not meaning to say that they are wrong!

[Mario Schweiger]

Caspius (as well as schmidti) has been split off from jugularis by BARAN (1976): Türkiye Yilanlarinin Taksonomik Revizyonu ve Cografi Dagilislari.
Because they never have found hybrids between two of the new three species.
All three may only be distinguished by their different color and pattern.
There is no really difference in pholidosis (wide overlaps).
See also FRANZEN et al. (2008): Die Amphibien und Reptilien der Südwest-Türkei

Mario