Tuesday, 30 December 2014

Heliaeschna uninervulata - Swarming at Cat Tien

On November 17 we were checking the road from the lodge to the fishponds in an open, disturbed, area, with some forest and shrub cover. Close to dusk, we were looking for Gynacantha. As luck would have it, a species appeared in good numbers, with several score dancing around. But not so lucky, they stayed quite high. Kameliya discovered a place where they were flying somewhat lower and I was able to net two females. In hand, they had very broad leaf-like appendages. But my mind was set on Gynacantha, so it did not occur to me this could be something else. It was only after Oleg Kosterin (thank you Oleg!) responded to a later email by me, that it dawned on me that this was a Heliaeschna. Venation in the wing made it clear it was H. uninervulata, a species that had been reported from Vietnam before (1953, Lieftinck), but otherwise apparently had gone unnoticed. It occurs widely over south-east Asia, so it probably occurs more commonly.

Heliaeschna uninervulata, female. In coloration and appearance rather Gynacantha-like. Note the single cross-vein in the median space.
Dorsal view of the frons
Facial pattern, rather simple
The distinctive leaf-shaped appendages

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