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

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

What goes there in the twilight? A tale of Gomphids*

* This entry was adjusted on December 31, 2019, following the publication of a paper in Zootaxa by Oleg Kosterin on June 12, 2019. The paper addressed the considerable confusion surrounding a group of similar Macrogomphus species, showing, amongst others, that M. guilinensis from Central and northern Vietnam (and China) is a junior synonym of M. albardae, occurring in a variety of distinct forms.

During the last week of June and the first two weeks of July I travelled around the northern provinces of Vietnam. I ran into almost 40 species of gomphids, some unexpectedly common. An eye-opener was that so many species are active just before dusk. Sometimes I would visit a stream in the afternoon and see only the occasional gomphid, to return in the last 30 minutes of daylight and see scores of them. There are some species that I encountered both during the day and in the twilight hour, there were some that were very much more abundant at dusk and there were some that I only encountered at dusk. For some, this may explain the paucity of records. For others it was truly surprising, as I had seen them previously at other places during the day. An example of this category was Nihonogomphus thomassoni. I had seen it, for instance in Huu Lien, earlier in the year regularly during the day. At a stream in northern Bac Kan Province I did not see any during the day, but the first males would start appearing during the last 45 minutes of daylight, to become common (say 20 specimens in a 200 hundred meters of stream) during the last quarter, some still there when it as almost too dark to see them.
Species that were observed at dusk were for instance Lamelligomphus camelus, Melligomphus ardens, Phaenendrogomphus tonkinicus, Macrogomphus albardae, Orientogomphus naninus, Stylurus amicus, and Burmagomphus vermicularis. Of these O. naninus and S. amicus were only observed at dusk, O. naninus commonly and in many places. Keith Wilson already mentioned the crepuscular behavior of O. minor in Thailand and suggested due to this habit it to be overlooked. It comes as no surprise that the similar O. naninus displays similar behavior and is much more common than its two previous records suggested. I encountered it in Bac Kan Province, Ha Giang Province and Cao Bang Province. On the other hand, several species regularly encountered during the day disappeared towards dusk, like Megalogomphus sommeri, or Labrogomphus torvus, or species of the genera Leptogomphus, Merogomphus and Asiagomphus.

Macrogomphus albardae I saw both during the day and at dusk, a total of 4 times in Bac Kan Province, at 3 different sites. This is a brilliant species, if only because of the weird appendages. It was also a species I really wanted to verify, after seeing possibles last year (in Ba Be and Cuc Phuong). It is widespread.

This is the female of M. albardae

A male at midday.

Appendages in dorsal view

In lateral view

And in ventral view

Orientogomphus (Acrogomphus) naninus was only seen at dusk, when males appeared to hover over the streams. It was encountered at many streams in semi-forested surroundings. I did not encounter any females.

Male hovering above a stream in Bac Kan Province

The appendages and posterior segments in dorsal view

The appendages in lateral view

Close-up of appendages in dorsal view

Finally, a species caught at dusk along two widely (about 80km) removed streams was Stylurus amicus. This species easily identified because of the relative length of S9 to S8, with S9 about 1.5 times longer. Karube already found S. clathratus in Vietnam, and one of the mystery gomphids of Sebastien may be a third species. S. amicus apparently had not been verified inside Vietnam before.

The magnificent club of Stylurus species, in this case of S. amicus

Macrogomphus*

*Somewhat adjusted on December 31, 2019. I left this entry in the blog, because it gives a nice insight in my early involvement with the astounding Odonate fauna of Vietnam, trying to make sense of it all with limited available literature. However, it is not at all in line with current knowledge on Macrogomphus. I left the text as it was, apart from parts in bold and the captions of the photos, adding the proper ID, but please see subsequent entries on Macrogomphus and check Kosterin (2019).  That paper paper addressed the considerable confusion surrounding a group of similar Macrogomphus species, showing, amongst others, that M. guilinensis from Central and northern Vietnam (and China) is a junior synonym of M. albardae, occurring in a variety of distinct forms.

On July 24 we were walking along a slow stream in open area (paddies) in Ba Be National Park when I noticed a large gomphid ovipositing on the muddy bank. I caught it and took some photos before releasing it again. At the time I did not realise it was a Macrogomphus. A week later, on August 2, we were walking in a completely different setting at a very different location, now in the village outside Cuc Phuong National Park, when I spotted a large gomphid sitting on an overhead wire. It was well out of reach, but with a tele lens I was able to take a few shots before it moved off. This again was a Macrogomphus, this time a male.

To my knowledge only two Macrogomphus have been recorded in Vietnam, M. rivularis and M. annulatus. [M. rivularis is in fact a junior synonym of M. albardae] The former species was described in 1914 by Foerster and apparently has not been recorded since. Although I have some pages of the article by Foerster, the relevant pages are missing. In surrounding countries several additional Macrogomphus species have been recorded. Asahina for instance mentions M. borikhanensis, M. thoracicus and M. matsukii [M. borikhanensis is also a junior synonym of M. albardae and M. matsukii is possibly not a valid species] from Thailand. Basically Macrogomphus has two groups, species similar in relation to the dorsum of the thorax. Those with ante-humeral stripes fall into the quadratus group, as do these specimens. The other group has large squares on the dorsum, like M. kerri and M. caudatus.

Of the possible quadratus group species, M. annulatus has the abdominal segments 3-8 all ringed completely, both in male and female. M. borikhanensis has a much darker thoracic pattern, with narrower yellow markings and the caudal appendages for the male are quite different, with the ventral branch very large, extending beyond the upper branches in ventral view. Moreover, the vertex is all black. M. matsukii also has complete rings, both in male and female, different caudal appendages and more extensive light markings on the face.

In fact both specimens are very similar to M. guilinensis [M. guilinensis is yet another junior synonym of M. albardae] as described by Chao (male) and Wilson (female). This species has incomplete rings, a yellow spot on the vertex, small conical caudal appendages with simple valvula vulvae (female), or upper appendages with outer branch longer than interior, and angled inferior appendages (with a "heel"). Also in ventral view, the inferior appendages extent laterally beyond the superior appendages. I am not aware of other records of Macrogomphus guilinensis in Vietnam and with M. rivularis unknown, I welcome comments on the identity of these specimens, but as M. guilinensis occurs in Guangxi, it is likely that it may also occur in North Vietnam.

The female Macrogomphus albardae from Ba Be

The dorsum of the thorax and frons. In fact the seperation in the middle of the yellow stripe on the frons is different from the drawing in Wilson. Tricky.

The ventral side of the tip of the abdomen, showing the vulvar lamina

The dorso-lateral view of the tip of the abdomen, showing the caudal appendages

The male Macrogomphus albardae from Cuc Phuong, high and dry on the wire. The thoracic and abdominal pattern very similar to that of the Ba Be female.

The view from below of wings and caudal appendages, see the close-ups

Close-up of the caudal appendages of the male, showing the inferior appendages protruding laterally beyond the superior appendages and the larger outer branch of the superior appendages

A slightly different angle