Tuesday, 28 April 2015

Hylaeothemis clementia - almost overlooked

Sunday April 26 I drove very early to Yen Bai Province along the QL32 for what was supposed to be a sunny few days in Yen Bai and Sa Pa. It turned out not to be that way at all. But while working my way up along the road after Nam Bung in Van Chan commune I checked the trickles and streams crossing the road and on one flushed a teneral small dragonfly. It attracted my attention by the bold yellow-and-black thorax pattern and the abdominal pattern with a large double spot on S7 not unlike Micrathyria species in the neotropics. As I caught it I assumed it was a Tetrathemis species, exactly because of these characteristics. It also seemed to have the black face with yellow band across. So I almost released it. But it did not seem right somehow, too large and the wings, although amber at the bases, where not amber across the complete inner wing. So I decided to take it along.

Monday evening, after another cloudy day, I had returned home and checking it in the evening noticed the peculiar secondary genitalia. Of course it now also dawned on me that the thorax markings were not right after all. I opened up the volume on Thailand by Asahina and with a strike of good fortune opened it as Hylaeothemis clementia. There it was!

A rarely recorded, but possibly overlooked, dragonfly, H. clementia to my knowledge has been recorded once in Vietnam, in Son La Province in 2003 (Sasamoto & Do, in Do & Dang, 2007). Son La is adjacent to Yen Bai Province, and the sight where is was recorded is about 100km away from my site, as the crow flies.

I found my specimen along a small stream with a few puddles in heavily grazed and degraded woodland on a hill side. As it was freshly emerged, this must be within its habitat range.

Fresh male of Hylaeothemis clementia, easily overlooked!
But both the central dorsal line and the lines over the humeral suture are different from T. platyptera.
The facial pattern is reminiscent of T. platyptera, which similarly has anteclypeus, postclypeus and antefrons yellow.
The hamulus is a clear give-away though, very different

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