There was some discussion about grass snakes recently, I thought the following statement from ARG UK helps to clarify the matter. Sorry if this is going over old ground that has already been covered.
In short… we still only have 1 native grass snake species, it has just been reclassified as a new sub-species
Natrix helvetica helvetica (formerly
Natrix natrix helvetica)
See link and full article extracted below…
http://www.arguk.org/get-involved/news/what-does-the-re-classification-of-european-grass-snakes-mean-for-our-native-grass-snakes
Following on from the recent publication of the scientific paper by Kindler et al., (2017), there have been some misunderstandings about the classification of our native UK grass snake. To clarify:
Then:
Until recently, two species of European grass snake were described:
Natrix natrix (found across much of Europe, including the UK) and
N. astreptophora (found in North Africa and Iberia). These two species are described by Pokrant et al., (2016) – which you can download here
http://onlinelibrary.wiley.com/doi/10.1111/bij.12782/abstract
Natrix natrix was further divided into around 14 sub species, with
Natrix natrix helvetica – our native UK grass snake, occurring in Britain, France, small parts of Germany, Belgium, Northern Italy, Switzerland and some of the neighbouring countries. Crossing the Rhine in Germany we had
Natrix natrix natrix which covered most of central and northern Europe. To the south of
Natrix natrix natrix, we had
Natrix natrix persa, which extended down in to the Balkans. Italy and some of the other islands (Sardinia, Sicily, Corsica) also contained other subspecies including:
Natrix natrix lanzai (Italy),
Natrix natrix sicula (Italy including Sicily),
Natrix natrix corsa (Corsica) and
Natrix natrix cetti (Sardinia).
Now:
This has now changed, with the advent of genetic sequencing based on mitochondrial and nuclear microsatellite DNA. This is described in a recent paper by Kindler et al., (2017) – which you can download here.
http://onlinelibrary.wiley.com/doi/10.1111/bij.12782/abstract
Everything west of the Rhine in Germany (more or less) is now
Natrix helvetica. This includes 'our' grass snake from Britain which is now designated as the subspecies
Natrix helvetica helvetica. Together with the four subspecies from Italy and its islands, these are all now considered to be sub species of
Natrix helvetica.
In short:
We had
Natrix natrix helvetica. Now we have
Natrix helvetica helvetica. Nothing extra - still only 3 snake species in Britain: one grass snake, the adder (
Vipera berus) and the smooth snake (
Coronella austriaca).
This is quite timely having seen a juvenile grass snake in my Salwarpe Garden yesterday.
Regards
Triturus