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New UK Species of snake? |
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PondDragon
Senior Member Joined: 15 Jul 2013 Status: Offline Points: 55 |
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I was surprised to see that the amount of genetic divergence between e.g. Natrix natrix, N. helvetica and N. astreptophora was in the order of several million years, so the taxa have clearly remained distinct throughout several successive ice ages / interglacials and presumably substantial range shift over that time. Interesting to know what would have been the situation during the glacial periods when all these multiple (sub)species would presumably have been squashed into fairly small areas of southern Europe, maybe reflecting their current distribution or maybe not.
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Robert V
Senior Member Joined: 06 Aug 2004 Location: United Kingdom Status: Offline Points: 1264 |
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A reasonable dissertation subject but good job the old copyrights are out on some texts. such research was done nearly 150 years ago. As you all know, Linnaeus identified the Natrix branch in 1758 and examined most if not all the so-called sub species. But Lacepede in 1789 disagreed and called for Natrix Helvetica to be identified separately as Coluber Torquatus /a, at least recognising that certain lineage was different.
what I'm a little confused about in this latest article is its resemblance to am article which appeared in the Linnean journal in 2016, but which said that 300 museum samples and 85 Grass Snakes had been tested. Please see below - sorry no link available!!! And are you really trying to suggest that during all that time no hybridisation occurred? Really. Was it worth all the fanfare??
...Europe has gained another snake Dresden, 22 February 2016. In collaboration with an international team, scientists of the Senckenberg Natural History Collections in Dresden have identified a new species of snake in Europe. In an integrative study, published today in the Biological Journal of the Linnean Society, the researchers were able to demonstrate that the Iberian Grass Snake does not constitute a subspecies of the wide-spread common Grass Snake as previously thought, but rather a distinct species. The Grass Snake is widely distributed across Europe and Asia; in many countries, this harmless reptile with the characteristic, pale crescent around the neck is among the most commonly encountered snakes. “It may well be due to this abundance that there are so many different views regarding their taxonomy”, says Professor Dr Uwe Fritz, Director of the Senckenberg Natural History Collections in Dresden, and he continues, “Depending on the author, the number of recognized subspecies ranges from 4 to 14.” In cooperation with the PhD student Carolin Kindler, colleagues from the Zoological Research Museum Alexander Koenig in Bonn and additional international partners, Fritz now discovered that the Iberian Grass Snake – previously considered a subspecies of the common Grass Snake – is in fact a distinct species. “Europe’s vertebrates are generally well-studied – the discovery of an additional species is therefore quite remarkable”, underlines a delighted Kindler. The team of scientists used various methods to study more than 300 snakes from different museum collections and combined this data set with genetic data of 85 Grass Snakes. “We connected external morphology, such as scale numbers, with characteristics of the skeleton and genetic features; and based on these results, we found out that the Iberian Grass Snake – Natrix astreptophora – constitutes a full species,” explains Fritz. The genetic studies also show that the newly discovered species does not share its habitat with the common Grass Snake Natrix natrix, whose subspecies are widely distributed throughout Europe and Asia. Natrix astreptophora occurs in the North African Maghreb region, on the Iberian Peninsula and in Southern France. Kindler explains, “the two species only meet in the south of France, near the Pyrenees.” But there is virtually no hybridization between the two species in this region – “strong evidence that Natrix astreptophora constitutes a separate species,” adds Fritz. As a hunter of amphibians and other small animals, the common Grass Snake, which can reach a length up to 150 centimeters, is tied to wet habitats – and these are increasingly threatened by the draining of wetlands, the regulation of river courses and the intensification of fish farming. The Iberian Grass Snake, however, is much less dependent on the presence of water than its wide-spread relative. Many grass snakes fall victim to automobile traffic; around some of the larger lakes, tourism poses yet another threat to the grass snakes. “The knowledge about which species we are dealing with helps us to better assess the threat level and to implement timely protection measures. This is of particular importance, since the Iberian Grass Snake prefers different types of habitat,” adds Kindler in summary. Pokrant, F., Kindler, C., Ivanov, M., Cheylan, M., Geniez, P., Böhme, W., and Fritz, U. (2015). Integrative taxonomy provides evidence for the species status of the Ibero-Maghrebian grass snake Natrix astreptophora. Biological Journal of the Linnean Society. |
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RobV
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Robert V
Senior Member Joined: 06 Aug 2004 Location: United Kingdom Status: Offline Points: 1264 |
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...And I know for a fact that Helvetica breeds with astreptophora because.... izer seen it wit my own eyes boss.... so who should I sue???
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RobV
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Iowarth
Admin Group Joined: 12 Apr 2004 Status: Offline Points: 743 |
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LOL - no point sueing them Rob - speaking as a lumper rather than splitter it won't stop new species being invented overnight just because they have found (at last!) scientific justification for some sub-species.
Chris |
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Chris Davis, Site Administrator
Co-ordinator, Sand Lizard Captive Breeding Programme (RETIRED) |
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PondDragon
Senior Member Joined: 15 Jul 2013 Status: Offline Points: 55 |
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The 2016 article was separating N. astreptophora from all the rest, the recent article is separating N. helvetica and N. natrix using the same methodology. From a very superficial reading of the 2016 article there were a very small number of hybrids identified along the narrow zone of overlap, but the vast bulk of the population was pure one or the other. So it seems that the hybrids tended to be unsuccessful over the long term, keeping the species separate. The same was true for hybrids between N. helvetica and N. natrix in the 2017 paper, but not for hybrids between N. natrix natrix and N. n. persa which occurred over a wide zone of intermediates indicating that these are not separate species. |
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Caleb
Senior Member Joined: 11 Apr 2011 Status: Offline Points: 660 |
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The 2016 paper is available here:
The new paper suggests that the grass snake species group is similar to other groups like fire-bellied/yellow-bellied toads (Bombina) and crested newts (Triturus cristatus, carnifex etc) which have narrow hybrid zones where the species' distributions meet.
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Suzi
Senior Member Joined: 06 Apr 2005 Location: United Kingdom Status: Offline Points: 1025 |
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Just an observation...I know a place with grass snakes with no water anywhere in the vicinity. No ponds or streams and the nearest being maybe half a mile away across a busy road. This grass snake site is heathland quite high up.
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Suz
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JamesB
New Member Joined: 02 Oct 2017 Status: Offline Points: 2 |
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Hi, apologies for bringing this back up. Could anyone answer a quick query re identifying Natrix Helvetica Helvetica vs Natrix Natrix? I've read numerous articles that state a more olive colour and blacker markings on Helvetica, as well as there being no yellow collar present. Is this always the case?
It may be a trick of the mind but I seem to recall seeing far more with yellow collar than without & certainly my local snakes all have one present. Are these therefore Natrix Natrix? Bad picture below and thanks! |
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Iowarth
Admin Group Joined: 12 Apr 2004 Status: Offline Points: 743 |
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Hi James
Perfectly reasonable query which arises largely because many of the articles which exploded through the media when this was announced were very poorly and, at best, confusingly written (if not totally inaccurately). Firstly, the UK/western European (except Iberia) grass snake (Natrix helvetica - maybe) generally has a yellow collar but occasional individuals or isolated populations may lack it (or appear to lack it due to it being very pale). This is probably most pronounced in Natrix helvetica cetti. This tends to be reversed with Natrix natrix spp. It is NOT however definitive. All the best Chris |
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Chris Davis, Site Administrator
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JamesB
New Member Joined: 02 Oct 2017 Status: Offline Points: 2 |
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Brilliant, thank you very much. Amazing how confusing the news articles managed to be, given how short most of them were! Much for me to learn but will enjoy doing so.
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