Scalmogomphus guizhouensis in Yen Bai

The weekend of 10 and 11 May I visited Yen Bai Province looking for dragonflies and escaping the hot (41 C) weather in Hanoi. The Saturday was mostly cloudy, but around Nam Bung and further on along the QL32 it was still great exploring. I ran into about 15 quite colorful gomphids that I could not identify. Both males and females were common and quite easily approached. At home, after some searching, I finally identified it as Scalmogomphus guizhouensis. In fact, to be fair, I identified it as S. wenshanensis. The latter was described in 2005 by Zhou, Zhou & Li. The former in 2000 by Zhou & Li. Scalmogomphus guizhouensis was redescribed based on a collected individual from Sa Pa by Do Manh Cuong (2008). I found almost no difference between the two species when comparing the drawings. Interestingly, Zhou, Zhou & Li make no mention of S. guizhouensis, even if one of the authors also described that species. They only compare it to S. falcatus and the grounds on which they do so (second tooth apically on inferior appendage, bifurcate anterior hamule) are shared between both species. Only the green stripe on the frons is cut in two by black line in the middle in S. wenshanensis. Be that as it may, the species is identical with the redescription by Do.

Male Scalmogomphus guizhouensis

The same, female

Another male S. guizhouensis

Another male

The female in the field

Apart from the bifurcate anterior hamule, also the appendages are typical, with the strongly downward hooked superiors and the inferiors with two teeth, one at basal third and one close to the tip