Tuesday, 8 August 2017

Barred Grass Snake...a new species but not new to the UK

Thought it worth adding a short post following the announcement in the media that the UK now has 'a forth species of snake discovered'.

Barred Grass Snake Natrix helvetica
Has always been in the UK, not just discovered

Information in the news has been extremely misleading (nothing new there) and in fact the UK has exactly the same number of species today as it had yesterday...three.

That's not to belittle scientific discovery. Indeed Europe now has a new species of snake but the UK still has the same number of species. The whole grass snake cline is confusing at the best of times but advances in genetic discoveries has opened up a whole can of worms (not just with snakes but across the board) where previously described subspecies are now being elevated to full species level in their own right. Something every birder loves...another tick!

Natrix helvetica
In the case of Natrix natrix helvetica (aka 'Barred Grass Snake' or just good old 'Grass Snake' if you prefer), it has been discovered through genetic analysis that it is in fact a separate species rather than a subspecies as previously thought. Scientists in Europe also found that where N. n. helvetica came into contact with Natrix natrix natrix (aka Eastern Grass Snake), there was little interbreeding between the two. You can read more about it here.

We must also remember the same thing happened not so long ago with the Iberian Grass Snake Natrix astreptophora, formerly a subspecies just like N. helvetica. Personally I've no doubt whatsoever that the same situation will arise again with some if not all of the other subspecies found across Europe - up to 14 depending on which author you side with. Next we could see N.n. cetti, N.n. corsa, N.n. fusca, N.n.gotlandica, N.n. lanzai, N.n. persa, N.n. scweizeri, N.n. scutata or N.n. sicula become full blown species. Great for anyone wanting an extra tick or two!

Perhaps all of the confusion in the media hasn't been helped by the use of English names to describe species either? So, just to put the record straight - yesterday we had 'Grass Snake' or 'Barred Grass Snake' Natrix natrix helvetica and today we have 'Grass Snake' or 'Barred Grassed Snake' if you prefer Natrix helvetica. Just a change in nomenclature.

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