Sinocnemis yangbingi - 1000km from Emeishan and new for Vietnam

On April 16 we were birding on the slopes of Mount Phan Xi Pang, at about 1800m ask when I noticed a damselfly interacting in a territorial dispute with a male Mesopodagrion tibetanum. It was about the same size and likewise perched with wings held open on leaves, but instead of a whitish blue pruinose abdomen tip, it had a bright blue abdominal tip. I relocated it after a bit of searching and after a few quick record shots decided to try to catch it by hand. I luckily succeeded. But what was it? Clearly something new for Vietnam. Today while searching through the literature I came across an article by Vincent Kalkman on Mesopodagrion and Sinocnemis from 2008. It helped me to the answer: Sinocnemis yangbingi, a peculiar species known from very few locations, the closest at 1000km distance in Sichuan at Mount Emei. Quite a range extension! As this is apparently an immature male, the colors are more vivid, but the pattern is the same as in the photos in Vincent's article and both the penile organ and the appendages are identical.

Sinocnemis yangbingi, male, immature

The same immature male

Note the orange mid dorsal stripe, which will disappear when the insect matures

Typical appendages in lateral view, S8 damaged in capture

Appendages in dorsal view

Note shape of distal segment of penile organ and thick hairs along shaft.