Anisopleura bipugio - also in central Vietnam

Hämäläinen & Karube described a new Anisopleura species from Lam Dong Prov. in southern Vietnam (technically at the very southern border of the Central Highlands) in 2013. I was never to verify it myself that far south, but in 2016 I ran into it several times. This is my third of fourth species of Anisopleura in Vietnam. In previous entries I introduced A. qingyuanensis and A. yunnanensis and a possible species novum from Pia Oac. The latter has different thorax pattern than A. yunnanensis, but its genital ligula and caudal appendages are seemingly the same and we could find no clear differences in DNA, so eventually decided not to describe it (Phan et al. 2018). Anisopleura is a tricky genus with a lot of look-alike species, so finding one that is remarkably different is pretty thrilling. This is certainly the case for A. bipugio, which has magnificent horns on its prothorax. I observed the species in Bach Ma National Park and nearby Quang Tri and Thua Thien - Hue Provinces. In Bach Ma it occurs together with A. qingyuanensis, which is common further north.

Male Anisopleura bipugio near the top of Bach Ma National Park, August 5, 2016

Close-up of male head, Thua Thien - Hue Prov., June 21, 2016. Females also have these remarkable horns.

Euphaea sanguinea, a new species for science

It has been busy. Busy with work, busy in the field here in the Netherlands, busy writing up some papers and before you know it, time is slipping without blog posts. So much so, that I have even failed to publish on the blog new species described from Vietnam in which I had some part. But here it is, a nice photo of a male of the newly described Euphaea sanguinea Kompier & Hayashi, 2018, published earlier this year in Zootaxa (Phan, Kompier, Karube & Hayashi 2018). This is a species localized in south central Vietnam and across the border in Cambodia (Kosterin 2016). It had been overlooked until now, because it is rather similar to E. ochracea, although, once you know it, it is actually obviously different, not only because of its appendages, but also by the very clear-cut red on S2-6. Below is a photo of a male from Bao Loc, Lam Dong Province, not far north from Ho Chi Minh City.

The newly described Euphaea sanguinea, a pretty male.

Xuan Son in late October

*This posting was updated on November 15, 2025. Please refer to Kompier et al. (2021) for more information: The genus Planaeschna McLachlan, 1895 and its subgroupings in Vietnam, with descriptions of three new species (Odonata: Aeshnidae). Also, the genus Planaeschna has been synonymized with Aeschnophlebia. I have added the current names between square marks [] below for clarity.

With apologies for the lack of postings in recent months. I have been busy writing papers.

Saturday October 21 I decided to go to Xuan Son. I have had little time recently, but now is the time the Planaeschna [Aeschnophlebia] fly there. In fact this was the only weekend available to go, so although the weather was not very promising, I went anyway. For three years I have been catching a small pale-faced Planaescha female, but never a male. I was getting a little desperate, as this was the last chance I had.

The weather was a little better than expected and quite soon I caught another female. Then several hours nothing, but fly by's of the large Planaeschna spec. nov. female and of female P. guentherpetersi [Aeschnophlebia ishigakiana guentherpetersi]. I did in the meantime tun into something unexpected: a male Coeliccia chromothorax. The 8th species of this genus along this 1.5 km stream. No idea how it got there. It is a striking species and I had never seen it on a large number of previous visits. Strange.

I also found a female Cryptophaea vietnamensis. In itself that is not strange, but it was covered in algae. I remember a discussion on this on the Facebook page on neotropical dragonflies. I do not remember ever having seen it in Vietnam, but apparently it does happen here too.

And then I caught a male "large" Planaeschna spec. nov. [described now as Aeschnophlebia tsuchi] and shortly after a much smaller one: the pale-faced male [In fact not the male of the pale-faced females, but Aeschnophlebia cucphuongensis]! I now have the males of all four species of Planaeschna occurring on this particular stream, 3 of them new to science.

Female Cryptophaea vietnamensis. Note the algae on the wings and abdominal tip!

Male Coeliccia chromothorax. Exciting find!

And there it is: Male pale-faced Planaeschna spec. nov. at last! [Aeschnophlebia cucphuongensis]

Appendages very different from P. [ishigakiana] guentherpetersi

And its pale face

Euphaea cyanopogon - an unexpected addition to the Vietnamese list*

*This article was adjusted August 5, 2019, as a result of the publication of a new species Euphaea cyanopogon Hämäläinen, Kosterin & Kompier, 2019. I retain the original text, but the species E. pahyapi is distinct differences with the present species, which now has been described as a new species.

On December 30 I was surveying streams in the forest at the northern side of Phu Quoc island when I noticed a smallish Euphaea species with uniform amber-colored wings. Because E. ochracea had been reported from the island from previous surveys and one of the reports showed a similar amber-colored winged specimen, for the time being I assumed it was this species. But at home checking it against the few specimens that I possess and many photos, both from myself and on the web, the suspicion rose that this really could not be E. ochracea. Not only in outward appearance was it different, but also structurally, like the caudal appendages and the vesicula seminalis. When I caught on to the fact that all adult males of species known from Vietnam have a completely dark face, whereas the Phu Quoc species had whitish-blue markings on the labrum and genae, I became convinced it had too be something else, E. pahyapi. In fact the species was not rare, although also not particularly common, but I saw at least 10 spread over several streams and on January 1 and 2 also noticed it in the forest more centrally to the island.

The species displays some very interesting characteristics. The males I saw (and I only saw males) had facial markings in varying degrees of intensity. A large, but centrally split, spot on the labrum and a large spot on the genae, anteriorly with an incursion of black. The wings were rather straight for the genus and with generally similarly shaped fore wing and hindwing. These were evenly colored from base to apex. Although the discoidal cells of the two specimens I collected are not entire (contra Hamalainen 1985), the cubito-anal space had only 2 cross veins in the fore wing of both specimens and 3 (once 2) in the hindwing, contrary to O. ochracea, which has mostly 4 (or even 5). This fits the description by Hamalainen of E. pahyapi. That species, just like my specimens, has a smooth vesicula seminalis, unlike the grooved vesicula of E. ochracea. The prothorax had vague markings in a few younger specimens, but became all black, contrary to ochracea, which has obvious place areas, and the thorax pattern also was much reduced and less rufous. The abdomen moreover was much darker than in ochracea, again fitting E. pahyapi. The measurements (2 specimens) are an exact fit with those given by Hamalainen for pahyapi, for abdomen, fore wing and hindwing (31-33mm; 29mm; 27mm). Especially fore wing tends to be longer in ochracea. And unlike any of the known species from Vietnam, but in line with E. pahyapi, S3 is adorned with a large area of long hairs. The caudal appendages are rather triangular in outline in lateral view, rather than rectangular.

E. pahyapi was described by Matti Hamalainen in 1985 from peninsular Thailand. Almost immediately afterwards Asahina published E. khaochongensis, which later was synonymized with E. pahyapi as a junior synonym. This is of particular interest, because in the description of Hamalainen the face is completely black, but in that by Asahina the labrum, genae and anteclypeus are all described as dirty blue. As almost all characteristics fit E. pahyapi, it seems quite sufficient to identify it as such. The only obvious difference is the pattern of the face, but given the description of its synonym E. khaochongensis, this is apparently within the range of variability. The other minor difference is that the discoidal cell in both collected specimens has one or two cross veins in all the wings, not entire as was the tendency for Hamalainen's specimens. Of course DNA analysis or further research may still identify the Phu Quoc population as different from that of the Malay Peninsula, but for now the identity of this species as E. pahyapi, not E. ochracea, seems well supported.

IUCN lists E. pahyapi as vulnerable, known from just 3 locations in Thailand and under threat of habitat destruction. As such, its discovery on Phu Quoc in good numbers is very relevant.

Male Euphaea pahyapi. Note the wings of almost similar wit and length, uniformly amber in color. This individual still with yellow-brown spots on prothorax and near ocelli. Also note that dorsal stripes are almost obscured and mesepimeron lacking the stripe bordering the humeral suture.

Another male, with dorsal stripe completely obscured, antehumeral stripe much diminished and mesepimeron with only a reduced stripe along the interpleural suture. This individual with completely black prothorax and cranium.

Close-up of S3 with the mass of long hairs on the proximal half

Close-up of the superior caudal appendages, showing their triangular shape, widest close to the base.

Close up of the smooth vesicula seminalis (left in the picture)

Close-up of facial pattern of one male, with extensive bluish white adjacent to the compound eyes, large bluish-white patches on the genae and on the labrum, and paler brown on the anteclypeus.

Another male, in which the markings are much reduced, especially adjacent to the eyes, but also split into two parts now on the labrum.

Bayadera melanopteryx and female Bayadera serrata

On May 25 I bumped into Bayadera melanopteryx for the first time. This is quite an easy species to recognize, courtesy of its darkened wingtips. It is a species that is widely distributed in the southern half of China and known to extend into the north of Vietnam, for instance around Pia Oac in Cao Bang Province and also around Sa Pa. My first encounter was near Sa Pa, but I also saw it several times around Pia Oac. The latest date was June 28.

There are distinct populations of the species in China with consistent differences in the extent of the darkened areas in the wing, so it is possible this is a superspecies, but until that is proved it is best to treat all populations as B. melanopteryx. The Vietnamese specimens all have the apical half of the outer wing blackish.

I know have also found B. serrata in quite a few additional locations to the spot north of Pia Oac where I first saw it last year. Apart from several sites around Pia Oac, it was also rather common close to Tu Le in Yen Bai Province and to my surprise I also ran into a female in Xuan Son National Park. Another addition to the already extensive list of that place. Earliest record this year was May 23 and latest was June 30. Apparently not so rare as thought.

The very dark body of the male of Bayadera melanopteryx

Which becomes very easy to recognize once you see the wingtips. Bayadera hatvan has clearly darkened wingtips and Bayadera hyalina has slightly darkened tips, but never as extensive and clear-cut as in B. melanopteryx

The female of B. melanopteryx has similarly darkened wingtips, although not as dark brown as in the male. The thorax pattern recalls B. hyalina, but see the completely pale metepimeron.

In dorsal view the curved dorsal stripes are also very different

Here is the first of two photographed females of B. serrata. In patterning of the thorax very similar to the male. This one is from Pia Oac.

Whereas this one is the female from Xuan Son, found inside the forest not far from the main stream.

Oviposting Bayadera species!

Saturday July 11 I was checking a stream near Nam Bung in Yen Bai Province. Yes, we know that now from the previous posts. But here I want to relate a special spectacle. In the morning I saw a great many Bayadera. Previously I had seen 3 species along this stream: B. hatvan, B. serrata, and B. hyalina. Of these B. hatvan was by far the commonest. This time I did not see B. serrata, but I saw many copula of the other two species. They could be seen ovipositing here and there in floating logs. But in the canyon there was a large tree that had been cut and toppled down into the stream, where it remained standing up. However, it stood in the middle of a water spray from a waterfall, making it soaking wet. There were a great many (several score) tandems ovipositing on it. Interestingly, the tandems formed single species clusters for some reason undoubtedly instinctively clear to them, but not to me.

Three tandems of Bayadera hatvan out of a great many more. It was not easy keeping my camera sort of dry.

A single tandem of B. hatvan. I lined the camera up with the trunk, but in reality they were almost vertical.

Two tandems of B. hyalina, braving the wetness. They were 20cm lower than the Bayadera hatvan tandems.

Adjusted angle of the same tandems of Bayadera hyalina.

Bayadera species - more confusion

Over the last few weeks I was lucky enough to find at least 5 Bayadera species. I already posted on Bayadera continentalis at Pia Oac. In the meantime I have also been able to capture a female, on May 20.

Interesting pattern with heart-shape laterally and a large elongated spot over the humeral suture. Bayadera continentalis female

Scan of the same female, displaying a distinct brownish wash to the wings

The next species that caught my attention was Bayadera nephelopennis, which apparently is not uncommon in the Sa Pa region. This species can easily be confused with Bayadera bidentata. Both have blackish males with a little pruinosity. B. bidentata is somewhat smaller and the females are in fact rather different in pattern, as I hope to show further on. Anyway, on May 18 I saw both a female and a handful of males in Sa Pa and again several males and a female on May 25.

Female Bayadera nephelopennis in hand

The dorsum of the thorax is quite distinctive. It has broad lines along the dorsal carina, but nothing over the humeral suture.

Another female on May 25

A male on May 18, showing the quite unicolorous appearance

But a pretty face, although this pattern seems shared by many species

 On May 25 I spotted yet another species at Sa Pa that I identified as B. hyalina. However, it does not have dorsal lines on the thorax and several other characteristics of a species. Whether that is an indication of variability or indicates a possible different species needs to be resolved at some stage, preferably through DNA analysis.

Bayadera hyalina (or possibly closely related species?)

Scan of dorsal aspect

 On May 23 weather was cloudy over Pia Oac, so I checked a stream further down and bumped into a whole bunch of Bayadera serrata.  A female in tandem showed herself fleetingly and was quite yellow, but I could not get a photo of her.

Bayadera serrata, male. A beautiful and distinctive species

Brightly coloured thorax and face

And distinctive bird-beak appendages

And finally the last species was Bayadera bidentata. Surprisingly this species showed up with several males and females at Xuan Son on May 30, where we had completely failed to see it previously!

Male Bayadera bidentata, with quite a bit of pruinosity on the thorax contrasting with the black dorsum

The usual pretty face

The female B. bidentata is rather different from B. nephelopennis. It has an irregularly shaped marking over the humeral suture, which is lacking in that species, and reversely misses the lines along the dorsal carina.

 Not to make this posting excessively long, I will publish the differences on the appendages between these species in another post.

Bayadera continentalis - new for Vietnam

Asahina described Bayadera brevicauda continentalis in 1973. On clear consistent differences, both morphological and in colour pattern, Hamalainen in 2004 elevated it to specific status as Bayadera continentalis. It is a species known to occur widely in southern China and thus, as so often, it comes as no surprise that on May 1 I labored my way along a trickle of a stream under dense forest cover on Pia Oac Mountain, quite close to the top at the northern side, that I ran into at least 5 males of this pretty species. It is quite distinctive by virtue of the shape of its appendages, its dark coloration with pruinosity on S8-10 and S1-3, and its smoky brown wings. Other characteristics include the all black labium and the distinct hairy thorax. To my knowledge this is the first record of the species in Vietnam, but it may have been recorded before. If so, I stand corrected.

Bayadera continentalis, here under flash the brown of the wings is difficult to ascertain

Here too the colour of the wings is difficult to see

But on this scan it is obvious

Parallel inferior appendages and apically strongly bent uppers in dorsal view

And in lateral view

And just because it is a nice face, the frontal view of the head

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