Asiagomphus mayhem - Vietnam is the place to be

August 2018 I finally was able to publish the results of 4 years of chasing Asiagomphus species in Vietnam. The paper that appeared in Zootaxa that year provided information on 8 species from this diverse genus. Asiagomphus acco is one of the easy species to recognize and had been recorded from Vietnam before. It is widespread and I published it on the blog long ago. Another species that is, at least in hand, easy to recognize is Asiagomphus reinhardti, which had only recently been described from neighboring Cambodia. The male has highly distinctive appendages, quite different from all other species in SE Asia. I found it both in Lam Dong Province and in Gia Lai Province. Here is an example in hand.

Male Asiagomphus reinhardti, caught May 17, 2016, near Bao Loc

As pointed out elsewhere in the blog, the most widespread species of Asiagomphus in northern Vietnam is probably A. auricolor. The original description by Fraser was based on a female and it had been hard to match it with its female. In my paper I give a first description of the male and provide further information on the female. Photos of this species are included already on this blog in past entries.

In neighboring Thailand Asiagomphus xanthenatus occurs and I was able to verify the occurrence of this species in central Vietnam, where I one lucky day ran into three males. Here is a photo of one of these.

Asiagomphus xanthenatus male, May 15, 2016 from Quang Nam Province.

Near Da Lat in Lam Dong Province, not that far actually from where I collected A. reinhardti (Bao Loc), I found a new species to science, Asiagomphus kosterini, which I reported already in this blog. 

That leaves us with 3 more species. One of these is a species with longitudinal stripes on the abdomen, different from all other species in Vietnam, although this pattern occurs on many of the northern species. This is Asiagomphus pacificus, which I found in Cao Bang Province and Bac Kan Province in the north. I reported this species already previously within this blog.

Which leaves us with two tricky species that I also already showed on the blog. Both turned out to be new to science and both are rather similar to some of the other species shown in this entry. These are Asiagomphus superciliaris and Asiagomphus monticola. Here are examples of both.

Male Asiagomphus monticola, Yen Bai Province, June 1, 2014

Asiagomphus monticola male, Xuan Son NP, May 31, 2014

And finally Asiagomphus superciliaris, Huu Lien Nature Reserve, May 24, 2014

Comparing the photos of these last three species, all similar to A. auricolor too, may leave the casual observer somewhat bewildered. Indeed, these species are rather difficult, if not impossible, to identify in the field without in-hand inspection. The details of the caudal appendages and secondary genitalia provide good clues. If you carry a copy of my Zootaxa paper, which provides these clues, you should be able to identify them and release them again.

Burmagomphus magnus - expected in Vietnam

On June 4 Odonatours visited the area of Cao Bang during its tour of northern Vietnam. On this day James Holden joined us from his 'home' in Cat Tien. Together we checked a large stream not far away from the town. While we were pre-occupied with other Odes, James took a photo of what appeared to be an unknown Burmagomphus. Burmagomphus vermicularis and B. divaricatus both occur in the area, but this was clearly different. After a visit to Pia Oac on the 5th, we went back to the stream on the 6th and were lucky enough to relocate this wonderful gomphid. Upon capture the details of the appendages could be verified and the initial suspicion this might be B. intinctus seemed confirmed.
Burmagomphus intinctus is only known from several specimens collected from Fujian in China, which is truly not exactly around the corner. And indeed, further perusal of literature (thank you, James) showed it to be B. magnus, described in 2015 from Hekou district in Yunnan Province in China, which is just over the border from northern Vietnam. It was therefore to be expected.

The original photo by James Holden. What is that?!

Two days later, probably the same individual in hand.

The strong hook on the posterior hamule

And the rounded epiproct and somewhat sinuous superior appendages

Gomphidictinus tongi, a wonderful discovery from Vietnam

In May 2016 I observed, but could not catch, a large Gomphidia-like gomphid in pristine forest just south of Phong Nha - Ke Bang National Park in Quang Binh Province in Central Vietnam. I thought it might have been Gomphidictinus kompieri, because of its deep forest habitat. I visited several times later in the season, but it rained every time and so I did not see it again. But this year I visited in early June and was more lucky. Not only did I catch a male, I also found the species next to the botanical garden of the National Park. And it clearly was not G. kompieri. It was a new species for sure, judging from the shape of the appendages, coloration and wing venation.

Not long after I was contacted by Zootaxa regarding a manuscript for a new Gomphidictinus species from China by Haomiao Zhang and colleagues. And what a surprise when this turned out to be exactly the same species: Gomphidictinus tongi Zhang, Guan & Wang, 2017. This lead to an interesting debate regarding its genus. Although the species is currently included in Gomphidictinus, in the same manner as G. kompieri was included in it, on the basis of the spine on the vesica spermalis, differentiating between Gomphidia and Gomphidictinus is not straightforward, not on the basis of this spine, nor on the basis of for instance wing venation. An overhaul of the genera, including DNA-analysis, is needed to solve this, but for now this fabulous dragon is included in Gomphidictinus as the third member of that genus.

Some unidentified Gomphidia / Gomphidictinus reported from Tam Dao by Natalia von Ellenrieder likely also concern this species, which therefore may be more widespread in Vietnam, apart from ranging widely in China (now recorded from Guangxi and Hainan). Interestingly, the two male specimens from Vietnam in below pictures indicate some variability in the maculation of the abdomen.

Female of Gomphidictinus tongi. It has wide flaps to S8, although not so visible here

Typical male showing already striking yellow markings compared to the two other species in the genus.

Slightly overexposed, so not as yellow, second male, but note extensive marking of S6 compared to the first.

Two new Stylogomphus species for science and for Vietnam

Today my paper on two new Stylogomphus species was published in Tombo. And with it two species I had found last year have received a name. The first I found along the Ho Chi Minh Highway just south of Phong Nha - Ke Bang National Park in May 2016 (and again this year) and also a little north of Khe Sanh. The other, a tiny species, I found perched in bright sunlight on a rock in a stream near Bao Loc in Lam Dong Province. Stylogomphus species are notoriously similar in their outward appearance, but have obviously different caudal appendages. That means that it is virtually impossible to separate them by observation or even photos, much like Leptogomphus species. Here are photos of both species.

Stylogomphus delicatus, a species with long and deeply cleft inferiors

Stylogomphus annamensis, a species with short and rounded inferiors

Macrogomphus albardae in Cat Tien*

*This entry was adjusted on December 31, 2019, following the publication in Zootaxa of a paper by Oleg Kosterin, which I had the pleasure of reviewing, on 12 June 2019. The paper addressed the considerable confusion surrounding a group of similar Macrogomphus species, showing, amongst others that Macrogomphus matsukii is a doubtful species and that records of Macrogomphus species identified as such from Cat Tien actually refer to Macrogomphus albardae. M. guilinensis from central and northern Vietnam actually is a junior synonym of the same M. albardae and occurs in a variety of distinct forms. Turns out that the 'matsukii' type gomphids I had been chasing for some time after first seeing them hover in the distance above a river in central Vietnam were conspecific with the species that I knew well from the north, but that based on previous misidentification and confusing literature had identified as M. guilinensis. Anyway, thanks to the careful work by Oleg the situation is now much clearer.

Original text:
James Holden had been reporting Macrogomphus matsukii from Cat Tien NP for a while and I decided to pay him a visit to get to see it in May. Last year I had seen Macrogomphus hovering over a large river at dusk (a habit shared by many gomphids, and certainly M. guilinensis) in Quang Binh Province, but had failed to ascertain beyond reasonable doubt that it was this species. Photos by James from last year had us initially discuss whether it was M. borikhanensis or M. matsukii, because the lateral pattern on the thorax had only two clear stripes. Facial pattern is very much like M. matsukii though. There seems to be some doubt whether these two species may in fact be conspecific anyway.

Commentary December 31, 2019:
Kosterin (2019) shows that the records of M. matsukii on which I based the above knowledge were in fact misidentifications of M. albardae, while M. matsukii remains a sort of phantom species. And he also showed that M. borikhanensis is another junior synonym of M. albardae. So the whole discussion on whether the Cat Tien specimens were one or the other was non-sensical in retrospect.

Below text with portions adjusted on December 31, 2019, in bold:
Just before I went to Cat Tien the rains picked up and the riverbed filled up quickly, so that circumstances had changes considerably when I got there on May 12. Indeed, we saw none, but on the 13th the waters had receded a little and the circumstances the species seems to favor (small trickles over the rocks by the side of the main stream) were restored. And towards dusk: there they were. 3 males hovering over the streams, for a short period joined by a Orientogomphus naninus. That distracted us and therefore I failed to get the stunning pictures I was hoping for. The different individuals had some variability in the extent of the middle lateral stripe, which was absent or represented by a small mark at the dorsal end. Otherwise they seemed perfect for M. albardae.
This is a widespread species, occurring widely in SE Asia. It includes at least the following junior synonyms: M. guilinensis, M. rivularis and M. borikhanensis.

Male Macrogomphus albardae, hovering at dusk over stream

Not a Bao Loc specialty - Heliogomphus chaoi

Karate (2004) described Heliogomphus chaoi from Bao Loc in Lam Dong Province in the south of Vietnam. This species is very similar in appearance to Heliogomphus selysi, a species occurring in for instance Thailand. H. chaoi differs especially in the shape of the vulvar scales of the female and the lack of prominent spines on the occipital ridge. In stead it has two small horns behind the lateral ocelli. Karube also notes that the superior appendages have a ventrolateral projection at the midpoint, to separate the male from H. selysi. Indeed, Asahina did not mention this for H. selysi, but I would love to see the holotype to verify this.

Anyway, last year I found this species to be common near Bao Loc at the type locality in early June. But a few days later I bumped into another small Heliogomphus in Gia Lai Province. Outward it was a little different in coloration. Notably, the superior appendages were more extensively white and S7 had a distinct anterior pale yellow ring. With differences between Heliogomphus species often slight, I thought it might be a different species, but checking it under the microscope I cannot but conclude the appendages and vesica spermalis are identical. If so, the slightly different coloration is likely nothing but a geographical variation. I concluded that the Gia Lai specimen is also H. chaoi. That species is therefore much more widespread than previously thought.

Heliogomphus chaoi in Bao Loc. Note it only has on S7 a pale yellow line along the dorsal carina and a lateral basal spot.

Another male at the same location

And the appendages in dorsal view

Heliogomphus chaoi at Gia Lai. Note the small yellow dorsal spot on S8 and the large anterior yellow ring on S7. But structurally it is not different.

The appendages in dorsal view, the white more extensive

Macrogomphus kerri - wonderful addition to the Vietnamese list*

*adjusted: it also occurs in Cambodia (thank you Oleg).

According to the IUCN website, Macrogomphus kerri may be an endemic to Thailand, where it is widespread, but uncommon. Well, sorry for the Thai, but it is not an endemic after all. 18 June 2016 I visited Gia Lai Province in the Central Highlands of Vietnam. A wonderful small, muddy stream in logged primary forest was a real treasure trove, with 6 species of Macromia flying at the same location, and many other goodies. This large and strikingly beautiful Macrogomphus species, easily recognizable by its bold patterning, was one of those. Not at all rare, I saw quite a few, including ovipositing females. Males tended to sit on or under bushes over the stream. Here are a few photos.

Beautiful male Macrogomphus kerri, perched

Another male, hovering over the stream in a dark place, hence the flash

Male in hand

And the rather similar female

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

Euthygomphus schorri - also in Vietnam

Oleg Kosterin published a paper last year in which he tackled some of the problems surrounding the genus Anisogomphus and the genus Merogomphus. Part of the solution was to erect a new genus, Euthygomphus. In the process he also described a new species: Euthygomphus schorri. Now, in the spring of 2016 I had caught some gomphids near Bao Loc in Lam Dong Province that for the moment I considered Merogomphus parvus. Their true identity now became immediately apparent. This too is Euthygomphus schorri. Not surprising really. The location where I caught them abounds in species that have recently been described for Cambodia just across the border, but are new for the Vietnamese Odonate fauna. In this case the shape of the caudal appendages and vesicle spermalis are the give away characters to identify the species, as Euthygomphus species are otherwise confusingly similar in outward appearance. A check in hand or close-up photo is necessary to clinch the ID. The caudal appendages are curved outward in dorsal view and have a distinct upward apical tooth.
This is the third Euthygomphus species found in Vietnam. The others are E. koxingai and E. yunnanensis (formerly thought to be E. parvus).

I refer to Oleg's paper "Reconsideration of the genera Merogomphus Martin, 1904, and Anisogomphus Selys, 1857, including erection of a new genus, with a new species and discussion of addition specimens from Cambodia" in Zootaxa 4171(1):51-76 for the details concerning the identification of these species.

Male Euthygomphus schorri, near Bao Loc, Lam Dong Province, 12 June 2016

Same male at slightly different angle

Nychogomphus lui, a Hanoi specialty

In 2011 Sebastien Delonglee already published photos of several enigmatic gomphid species that occur in the Hanoi region. Eventually one of these could be identified. It was Nychogomphus lui, described by Zhou, Zhou and Lu in 2005.

Apparently this species inhabits large slow rivers and the Red River is perfect for it. But it is a bit like Gomphus flavipes in Europe, another inhabitant of large rivers. That species too is best found by looking for exuviae of freshly emerged specimens. Nychogomphus lui emerges at the end of May and in early June. Sebastien has seen them for instance from a window perched in a tree! But how to reliably find them? In other years I could not. But this spring we discussed the area along the Red River where the Anax indicus appeared. It had some open forest areas close to the river. Might this be a good place?

Sebastien recently texted me to say he had seen a female. Soon after he found two more, on different days, all fresh. So today I went to the area, sweating it out (37 degrees in the shade). And found Nychogomphus lui, both a male and a female, perched in the shade close to the ground. Both were fresh. So this is the way to find them! Maybe they visit the river at dusk when mature, as other species of Nychogomphus do. Or maybe they mate elsewhere and the males do not return. We hope to find out.

For now this is the only place in Vietnam where the species has been found, but it may be more widespread. Generally we avoid the large rivers of Vietnam when we look for Odes, so it may be overlooked.

The female as I first found it, perched on a leaf. The color of the eyes shows she is very young, as is also evidenced by the shine of the wings.

She has amber wing bases. The wind was bothering her, so after this shot she took off

But when I turned around there was this wonderful fresh male! He had appeared while I was taking pictures of the female. Note the waved inferiors and black tipped superiors.

The same male in dorsal view

A new species of Asiagomphus*

*Updated January 1, 2020 based on the publication in 2018 in Zootaxa of my study of the genus Asiagomphus in Vietnam, which included the description of this species as Asiagomphus kosterini.

April 17 I was checking streams near Tuyen Lam Lake at Da Lat. It started as a sunny day and around 9.30 I spotted the first gomphid, perching in the middle of the stream on a stone. It was immediately obvious from the extensive yellow on the terminal segments that this was something I had not seen before. It took some effort, but eventually I was lucky enough to be able to net it. In hand my suspicions that it was an Asiagomphus species were confirmed. A very interesting species, with extremely extensive yellow markings and widely expanded S7-9. Patterning was otherwise in line with Asiagomphus and the appendages were also typical of the genus. But it is not any of the other 4 species (at least) I have seen in Vietnam and it is not any of the known species from South-East Asia either. A wonderful species and new to science! It was rather common at the stream, with at least 10 different males observed and a few females seen ovipositing.

I eventually published this species as Asiagomphus kosterini, one of a total of eight species of Asiagomphus I could confirm in Vietnam.

Asiagomphus kosterini. Note the extensive yellow markings on S7-9. A beautiful and striking species.

A male in dorsal view, showing the massive club

And in lateral view

The appendages and terminal segments in dorsal view

Holden - James Holden... James is back in Cat Tien - Microgomphus chelifer

I learned the other day that James is back in Cat Tien National Park. James already spent quite a bit of time there looking for dragonflies in the recent past and now is looking to add more to the list. A few days back he contacted me on an unidentified small gomphid. I was happy to help out and could identify it as Microgomphus chelifer thelyphonus. This species is known from Thailand, but new to the Vietnamese list. There is another Microgomphus species in Vietnam, M. jurzitzai, described by Haruki Karube, also from the south of Vietnam, but that species has quite different appendages. The epiproct for instance is much more "hooked". Here below a few shots of this interesting discovery.
James was also able to take a nice photo of Burmagomphus asahinai, which I also reproduce here. Let's hope he will discover more goodies in the next few months!

Female Microgomphus chelifer thelyphonus, courtesy of James Holden, at Cat Tien NP, 11 Dec 2015

The male of the same species, in hand, same date and place, courtesy of James Holden

Appendages of the male in dorsal view. What looks like two pins extending from the epiproct are in fact two branches originating from the cerci.

And a nice photo of a species already recorded from Cat Tien by James: male Burmagomphus asahinai, photo taken in 22 August 2015, courtesy of James Holden

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