Thursday, 17 July 2014

Nepogomphus walli - new for Vietnam

Nepogomphus walli is a small gomphid recorded from Thailand, Laos, Myanmar, Malasia and as far west as India. It is said to be tolerant of disturbance and is not considered threatened. Due to the distinctive appendages of the male it is not difficult to identify. But as it had never been recorded in Vietnam (to my knowledge at least), it still came as a surprise when I ran into at least 4 freshly emerged specimens on June 23 and again into 2 at the same stream on July 8. The stream had a rather sandy substrate and was very shallow. It was about 1 meter wide and ran through a cleared area, with swampy pasture for buffalo. It was bordered by shrubbery in places and the hills around the clearing had forest. Indeed a species that seems tolerant of some disturbance. I never saw mature specimens, sadly. Also, the markings on the thorax are a little different than expected, with the antehumeral broader and longer than in Thai specimens and connected to the collar. I judge these to be geographical variations, as appendages are identical to Thai specimens.

Nepogomphus walli, freshly emerged. A male.

In hand, genital lobe still green, appendages almost translucent

Female Nepogomphus wall, freshly emerged

Appendages of male in dorsolateral view, after hardening in captivity

The same in lateral view
And in ventral view

Genital lobe hardened and blackened

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