Wednesday, 2 September 2015

Petaliaeschna tomokunii - the other Petaliaeschna

Haruki Karube described Petaliaeschna tomokunii in 2000 from Pia Oac in Cao Bang Province. Superficially this is a species very similar to P. flavipes. Indeed, it is easily overlooked as this species. I had observed P. flavipes both in Yen Bai Province and at Pia Oac. This year I carefully checked specimens at these sites and found that P. tomokunii flies at exactly the same places, although it appears to prefer the late afternoon, rather than the evening. I caught them both at Pia Oac and at Yen Bai patrolling over puddles on trails. In hand they are basically similar to P. flavipes, but the male has pointed rather than blunt appendages, making it easy to identify in hand. There luckily is another difference. P. tomokunii has the complete face and frons yellow-orange. In P. flavipes the upper edge of the antefrons is darker and the postfrons has a vague dark T-spot. This allows the females to be separated in hand too.
This is a spring species, like P. flavipes. I observed it between May 14 and June 29.

Male of Petaliaeschna tomokunii. Very similar to P. flavipes

But the appendages are quite different, both in dorsal view, as here, and in lateral view (see below). They are decidedly pointed.
This is the lateral view (not so sharp, sorry) 
And this is the all-yellow face and frons

A scan of a female in dorsal view, showing the unmarked frons

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