Bluetail, Extremadura Spain (1 Viewer)

[Muppit17]

Found today in Ibores, Extremadura this Bluetail seems to have mix of features. In addition to it being almost white, the bluetail is very limited in extent and has the dots more typical of Scarce. The thorax pattern seems more like Iberian - perhaps the more expected species here.

The pterostigma don't seem to quite fit either

Comments would be most welcome

 

[pdwinter]

Ischnura graellsii female. Similar attached - I will dig out some more pics tomorrow after car serviced and mot'd!

 

[pdwinter]

A couple more - similar thorax colour but illustrating that female Iberian BT are extremely variable in the amount of black on S8. Once you have established it's a female then female pumilio can be eliminated because it never has a blue 'tail'.

 

[Muppit17]

A couple more - similar thorax colour but illustrating that female Iberian BT are extremely variable in the amount of black on S8. Once you have established it's a female then female pumilio can be eliminated because it never has a blue 'tail'.

Thank you, Paul

I had no doubt when I found it that it was graellsii, but as you say they are remarkably variable (and in my opinion beyond what is indicated in the textbooks) both in colour and extent of the markings.

I am hoping to reacquaint myself with Saharan vs Iberian in a couple of weeks

 

[pdwinter]

Thank you, Paul

I had no doubt when I found it that it was graellsii, but as you say they are remarkably variable (and in my opinion beyond what is indicated in the textbooks) both in colour and extent of the markings.

I am hoping to reacquaint myself with Saharan vs Iberian in a couple of weeks

Yes - you do need to have a lot of books to discover the variability. I don't have one single book on my shelf which covers all the forms - and none that mention the black females that I see! Yours is a "Type B" immature female.

If you have access to the academic site Researchgate you can get downloads of Adolfo Cordero-Rivera's papers on studies of Ischnura graellsii which add a lot more detail than the field guides have room for - I've attached one that I think is useful although people might need to use Google Translate if they're not used to reading spanish odonata papers.

 

[pdwinter]

This is from another of Cordero's papers - showing the colour changes in females over time.