Some interesting gomphids from Quang Nam

On 25-27 September I visited Quang Nam Province around P'rao on the HCM Highway. I ran into quite a few interesting gomphids and I would like to share here some of them. Price for most interesting on the 25th goes to a Leptogomphus species. Recently I had a conversation with Haruki Karube on Leptogomphus uenoi, for which he recently published the male. Before that the species was only known for females and one could argue that the male leads a secretive life. But we concluded that maybe it was just overlooked, as the appendages are rather similar to those of L. perforatus. Well, I caught a Leptogomphus and in hand concluded it was probably L. perforatus, but somehow the ring of the inferior appendages seemed closed and I decided to collect it. Lucky too, for at home it dawned on me this was L. uenoi! The outer edge of the inferiors is straight, but the inside edge curved.

Leptogomphus uenoi male, a typical Leptogomphus species

But look at the appendages! A neat ring and almost straight outer edges.

 On the 26th I bumped into a multitude of interesting species. I was very happy to see quite a few Nepogomphus walli. Males were congregating in a fern at a particular stretch of the stream. I had so far only seen this species in Cao Bang Province.

Nepogomphus walli in hand, with its typical yellowish wollen base of the superiors

One of the males perched, this one not on a fern

Also interesting was the Lamelligomphus sp. that I had seen in spring much further north, in Nghe An Province. It was quite common here.

Lamelligomphus sp., a smallish species with interestingly very dark S2. Some individuals had a small yellow spot posterior of the auricle. It is similar to L. hainanensis, but has no protrusion of the inferiors.

A real surprise was the Nychogomphus flavicaudus on a larger river, where 3 males were hovering in the middle of the day. There were no differences with the specimens from Cao Bang I recorded in spring. Same size and same pattern on the thorax (only an antehumeral spot).

Male Nychogomphus flavicaudus, at least, if flavicaudus is a valid species

The last cool species I want to introduce here is Burmagomphus divaricatus. I had only recorded a freshly emerged specimen in Cao Bang in spring, but here I saw several adult males.

Here is one of the males in hand. The pattern on the dorsal side of the thorax is a little variable.

Another, similar, male perched

And the appendages in dorsal view

Nepogomphus walli - again

Last year I was bumped into several freshly emerged Nepogomphus walli specimens when checking the slopes on the south side of Pia Oac mountain on 23 June and again on 8 July. I was happy that this year I found an immature male to the northwest of the mountain, but also in Cao Bang Province, about 60km from the previous location, on June 18.

Nepogomphus walli, immature male, showing the typical white superior appendages with swollen base and black tips.

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