Species: Tetrathemis irregularis hyalina
Common name(s): Elf
Habitat: Forested ponds
Provinces sighted: Khao Yai NP (Nakhon Ratchasima); Krathing Waterfall (Chantaburi)
In flight (that I have seen): July
Species easily confused with: Tetrathemis platyptera
Well, I think I can finally put this species into the 'seen' bank. Going all the way back to 2011, I saw what I thought was Tetrathemis irregularis hyalina. Noppadon agreed. However, I think I actually got the two species (T. platyptera) as they were living side by side. In fact, I was so confused that I actually decided to not count it as a record, especially as I didn't think it could be found as high up as Khao Yai. That is until I saw it again seven years later in Chantaburi. Now, I am convinced it is in fact the same species and I should have had more faith in Noppadon's ID (he is never wrong haha).
It is very similar in appearance to its more common cousin but there are subtle differences. The easy way to separate them is through the almost clear (or hyaline) wings as well as the reduced size of the markings on the abdomen.
Though I don't have photos of the male to hand, I think I may have seen it but need to look back through my ever-growing number of hard drives. For now, I will just add the female pics.
Here is the female from Chantaburi which I saw last month.
... and here is another female I saw in 2011 just outside Khao Yai (in hand).
I will upload any images of the male (if I have any and if I can find them!)