April 2 - Huu Lien and first gomphids

April 2 was a nice spring day to look for the first gomphids of the season in Huu Lien Nature Reserve. As always, the first impression was of clearance progressing, but like last year end of March, Trigomphus kompieri was about at various locations. The first I bumped into was a female, but like last year, I could not catch it and did not get a picture! Trigomphus is genus of early gomphids. Paragomphus may actually be year round, although rare in the winter, I think they may be around. Anyway, there was a male about too, interacting with the Trigomphus. I also saw quite a few Paracercion melanotum and fully mature Gynacantha subinterrupta. Below a few photos.

The first male Trigomphus kompieri of the day, a little difficult to get a clear shot.

And the third. Somewhat easier. The second eluded the camera.

Paragomphus capricornis against a muddy stream background.

Paracercion melanotum male

And Gynacantha subinterrupta showing well

Exciting new Gynacantha species for Vietnam (and the world): Gynacantha cattienensis*

*Entry adjusted after publication of this species in Zootaxa in May 2017 as Gynacantha cattienensis.

Middle December last year James Holden contacted me to report a spectacular Gynacantha species from Cat Tien National Park. Apparently it was quite common at a certain stream, where it could be observed in good numbers during the day time, flying across the stream. Photos showed a very interesting species indeed. The massive epiproct are only matched in southeast Asia by those of G. khasiaca, a rare Indian species that has almost never been observed, although there is a recent record from Bangladesh. The appendages depicted in Fraser (1936) are very similar, although there are in fact, if one looks closely, also differences. This may be due to the drawing, but maybe the differences are real. What is more, G. khasiaca has a grass-green thorax with spectacular dark stripes over the sutures, quite different from most species. The specimens from Cat Tien are a more dull olive green and lack these bold stripes. There are other differences, but in fact there are more similarities, whether in relation to the amber markings at the wing bases or the exact match in size. It will go to far to discuss all here, but suffices it to say that the species from Cat Tien is in the very least a different subspecies and possibly, and that would be truly amazing, a new species of Gynacantha, closely related to, but sufficiently different from, G. khasiaca. Currently we are trying to verify the exact details of the specimens used by Fraser and deposited in the British Museum. Below photos taken in December, of relatively fresh specimens, by James, and of last weekend, of old specimens, by myself. More details will follow when the time is right!

Scan of old male, very dark. Note dark amber wing bases and long epiproct.

Old male in lateral view, showing olive-green thorax and blueish pattern on S2. Eyes blue, not green as in Fraser's description

A fresher male in December, courtesy of James Holden. Note again the dark wing bases, the long appendages and epiproct and yellow frons with blackish T-spot.

Gynacantha bayadera - yet another Gynacantha (species 9)

I had long been looking out for Gynacantha bayadera in Vietnam. According to the IUCN website it is a widespread species, occurring from India to the south of China. Is is mentioned as native to Vietnam. However, until now I had not been able to find it. After James found Gynacantha khasiaca, albeit probably at least a new subspecies, at Cat Tien, the tally for Gynacantha species recently in Vietnam was already at 8. This includes the record by Ellenrieder et al. of Gynacantha hyalina from Cuc Phuong. On January 1 I finally caught up with a female Gynacantha bayadera, easily identified by the apple green thorax and face and plain frons (no T-mark) near Duong Dong lake on Phu Quoc. The next evening I also caught a male along a forest road at the north side of the island (where it flew with G. basiguttata and G. subinterrupta). Clearly it is not a rare species on the island. The male too is try green, with unmarked frons.

Male Gynacantha bayadera, a pretty, very green, small species

The female, likewise very green

The appendages of the male

And the (almost) unmarked green frons

The male of Gynacantha basiguttata and a male G. japonica thrown in

November 21 I went to Huu Lien to look for the enigma Planaeschna cf. guentherpetersi again, but did not see it. I did catch an Aeshnid that passed overhead in the forest and was very happy to find it was a splendid male Gynacantha basiguttata. I had caught the female a few weeks back too. Apparently it is not that rare inside the forest. The other cool thing I saw was a communal roost of Cratilla lineata. I had seen that in Potamarcha congener, but this was new knowledge to me. At least 15 bundled together on a hanging twig.

On November 22 I went to Xuan Son and looked for the small pale-faced Planaeschna there. I did see one female, but failed to catch it. It was mostly an uneventful day, but I saw a few Gynacantha japonica and was able to take some pictures. Another unexpected species was Trithemis pallidinervis at the river crossing, which I had not seen this far north. And a fine male Ceriagrion chaoi was another nice one. Not at all that common, although regular at Xuan Son.

Very fine male Gynacantha basiguttata, note the dark wingbases.

Scan of the same male. Note the long and slender epiproct and the wingbases.

Pretty male Ceriagrion chaoi

Gynacantha japonica, note the pale epiproct.

And a surprise female Trithemis pallidinervis

Gynacantha basiguttata in Huu Lien

Today I visited Huu Lien to try once again for the Planaeschna cf. guentherpetersi, but I failed to see it (although I saw two possibles hunting at tree top level in the late afternoon). But when I made my way back through the forest at dusk I saw quite a few Gynacantha. Most were immature G. subinterrupta, but one larger species whizzed by and was netted with a little luck. To my large surprise it had extensive dark basal patches to the wings: Gynacantha basiguttata. I had seen this species in the south, in Cat Tien National Park, but did not expect it at all this far north. After all, Huu Lien is almost in China. This is a large species. The female I caught was 76mm without the (broken) appendages.

Female Gynacantha basiguttata, a large species, easily recognizable by the dark wingbases.

Gynacantha ryukyuensis - an exciting duskhawker!

June 16 I visited Cuc Phuong National Park and towards dusk visited a field with several muddy areas along the forest edge where earlier during the day I had seen Gynacantha subinterrupta. I admit it, I was rather jealous of the Gynacantha hyalina recorded in the park by Natalia von Ellenrieder et. al. in their recent publication. So I wanted to see if I could get lucky too.

I noticed a few Gynacantha males that appeared to be G. subinterrupta, hovering in their characteristic way by the forest edge. But when it got really dark I noticed some patrolling Gynacantha along small trails through the grass, just flying up and down. I was able to catch one and was immediately struck by its weird coloration. The thorax was mostly yellow. Moreover, the inferior appendage was whitish, so clearly this was not G. subinterrupta. But also not G. hyalina. So what was it?

It took some searching, but finally it dawned on me that this should be Gynacantha ryukyuensis, a species known from islands between Japan and Taiwan, from Taiwan and from at least Hongkong. But not (yet) from Vietnam.

A beautiful species, Gynacantha ryukyuensis. Yellowish thorax, but with largely sky blue metepimeron. Note the little yellowish squares at the anterior ventral part of segments 4-7.

In dorsal view the deep yellow frons with black T is obvious, as are the greenish eyes (blueish in male G. japonica) 

The appendages, with epiproct less constricted in posterior half compared to G. japonica.

And in lateral view

March 28, first trip to Xuan Son of the season

The weather forecast said that west of Hanoi might be sunny in the afternoon, so I decided to drive to Xuan Son today. As is often the case, the forecast was wrong, so a cloudy day. Nevertheless I encountered at least some goodies, although nothing unexpected. Euphaea masoni was already very common and E. guerini was out and about too. In the damselfly department Mnais mneme was common too, and I saw the first Pseudagrion pruinosum of the season. Orolestes selysi was also present in decent numbers at the "Gynacantha puddle".
I was really hoping to see Nihonogomphus schorri, which had been omnipresent in April last year. Cloudy circumstances made it impossible to judge whether it is already common in March, but I saw one male briefly. A first female Macromia flew by. Could not verify the species though, shame. And at the "Gynacantha puddle" a few Cratilla lineata and quite a few adult or semi-adult Gynacantha subinterrupta were huddled in the bushes. All in all not at all bad, given the time of the year and the weather.

Not the best of photos, but anyway, Nihonogomphus schorri, as soon as the sun showed itself, no matter how short.

Female Rhinocypha perforata, quite common

And the male of Rhinocypha perforata. See the lateral thorax pattern. It is the same as in the female, although the forum is very different.

Neurobasis chinensis is a common damsel, but also very pretty, especially when it displays the top side of the hindwing.

The female of Neurobasis chinensis, with the typical double white dot.

Euphaea masoni already very common. This specimen kind enough to keep its wings open, displaying the typical translucent base and tip in the forewing and the reddish brown luster to the inside of the wings.

But the outside is dark blueish

Mnais mneme male, this one already pruinose on the thorax, a feature missing in Mnais andersoni.

The female of Mnais mneme, specimen with reddish veins

Immature (and already missing a pair of legs) Mnais mneme. When there is no pruinosity on the thorax it can be separated from Mnais andersoni through the structure of the penile organ.

Gynacantha subinterrupta with its typical abdominal pattern of oblique light bands. This individual almost adult, but the thorax still not fully green and the face still whitish.

Face of the same individual, showing cream white, not yet yellow.

Different male, this one with yellow face and green thorax, fully mature

Flashback - trip to Cat Tien NP 6-9 February 2015

In early February we spent a few days in Cat Tien National Park. It was very dry. Not a drop of water in the forest - virtually. But the fishponds were still productive and the odd stream or trickle also provided some species, but everywhere in low numbers. Clearly middle of the dry season is not the best time for Odonata here. Consequently we did not find anything new for the park list. But some species were very present and one was Gynacantha basiguttata, of which we saw several along the road through the forest, now adults.

Another species that I had seen only once, and that previously eluded photographic capture, was Rhyothemis triangularis. I was able to take pictures of a freshly emerged specimen.

And lastly, one evening, as I was heading back to the lodge, I ran into a roost of Potamarcha congener. An exceptional spectacle!

Gynacantha basiguttata female, now fully mature. Note the dark smudges at the base of the wing along the subcosta.

The face of the same female

A little extra: male Agriocnemis nana. I saw only a few, but what a delight.

Roost of Potamarcha congener. How many in the photo? I count at least 50.

Fresh male Rhyothemis triangularis, the only one seen.

Yet another Aeshnid hunt at Xuan Son

On November 29 I drove again to Xuan Son with the objective of finding Planaeschna species. It was a brilliant sunny day, possibly the last of the year, so maybe the last chance to find additional males. In a way I was lucky. There were Planaeschnas all over the place. However, they were all females. Over a dozen Planaeschna guentherpetersi were around and one of the similar, but different, Planaeschna sp., also a female. I hoped hard for a male, but although I saw a male fly by in a hurry, there was no chance to catch any.

Two other Aeshnids were around. I saw literally hundreds of Boyeria karubei at dusk and a few during the day and I saw a male Gynacantha japonica hanging in a bush. Below a few photos.

One of the several females Planaeschna guentherpetersi that I caught. A record shot. Note the typical pattern on S2.

Another female discovered perched. Note the typical pattern in the dorsum of S2 and the yellow wing bases. 

The female Planaeschna sp., different in for instance the pattern on S2 and the much shorter cerci.

Facial pattern of Planaeschna sp.

Hanging male Gynacantha japonica. Note the small, light-colored epiproct.

One of the many Boyeria karubei around

Gynacantha demeter, an addition to the Vietnamese list*

* This entry was published originally as Gynacantha dohrni. After discussion with Oleg Kosterin, I agreed that this should be rectified and published here as G. demeter. It took a while to get round to doing so. The below text is adjusted (on December 24, 2019) in places in line with this new insight.

During our visit to Cat Tien National Park we saw many smallish Gynacantha of which the males would take up hover stations in the lodge garden or along shallow streams in the forest or also along the roads. I was able to catch several males and females at various locations. They were characterized by a very small and constricted epiproct, largely straight superior appendages with somewhat diverging tips and a median basal hump, a rather broad S1-2 with huge blue colored auricles and a yellow face with a dark anterior edge to the postfrons. The hindwings were 41-42 mm, the total body length around 61 mm. It took a bit of searching, but in the end I was able to identify it as Gynacantha demeter Riss, 1911, a species known from for instance Singapore, Thailand and Cambodia, but as yet not from Vietnam. This species is very close in appearance to Gynacantha dohrni Krueger, 1899. The characteristics of my specimens (superiors 6 mm long, diverging tips) fit G. demeter very well, and S2 is also less wide than expected for G. dohrni. With G. demeter also recorded from Thailand and nearby Cambodia, it is not a surprise to find it at Cat Tien.

Male of Gynacantha demeter. Note the straight superior appendages and tiny epiproct and typical coloration of S1-3.

Likewise, the female of Gynacantha demeter

The appendages of the male, note the median basal notch and diverging tips

Close-up of the constricted and very small epiproct

Frons of the male with distinct dark anterior margin, but indistinct T-stem

Close-up of the pattern of S2, with very large blue auricles

The apical segments of the female, with exposed ovipositor