Wednesday, 18 September 2013

Drepanosticta sp.

This summer, just after arriving in Vietnam, we went to Ba Vi. I had already visited the mountain in May and seen some Drepanosticta damsels and now back in Vietnam was ready to go and clinch their ID. Sadly, there were not many around, in fact on July 13 I saw only one. Maybe it is a spring species. Anyway, as it kept to the shade, I could only make a record shot and with the flash, the blue on the abdominal tip looks whitish. As you can see from the close-up, it is actually really blue. The close-up also shows the shape of the appendages. There are several species that have rather similar appendages and, to some extent, coloration. These are D. vietnamica, which has a dorsal process on the upper appendages, and a lateral stripe on the synthorax, D. brownelli and D. hongkongensis, which both have smoother appendages without the obvious inner lobe about 1/3 from the tip. Both also have the prothorax either dark with lighter anterior edge, or all dark, whereas the species from Ba Vi (not clear in these pictures) has a clear straight blue line along the anterior edge of the pronotum and a blue anterior lobe. Also, D. brownelli has whitish abdominal tip. Although clearly closely related, the Ba Vi species appears to be something else. Next spring, time to collect and describe.

Drepanosticta sp., male. Due to the flash abdominal tip not as blue as in normal light.

Appendages, showing inferiors tapering into an acute point and superiors with large lobe on the internal side.

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