Yet another Aeshnid hunt at Xuan Son

*Post updated on November 15, 2025. The genus Planaeschna has been synonymized with Aeschnophlebia. Also, Kompier et al. (2021) treated the Planaeschna [Aeschnophlebia] species of Vietnam in detail. Names are adjusted below between square brackets [].

On November 29 I drove again to Xuan Son with the objective of finding Planaeschna [Aeschnophlebia] 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 [ishigakiana] 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 [sihigakiana] 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. [This species, described as Planaeschna sp. 1 in Kompier et al. (2021), likely is Aeschnophlebia owadai.]

Facial pattern of Planaeschna sp.

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

One of the many Boyeria karubei around

A few more goodies from Xuan Son

October 26, in Xuan Son, I had, besides the Calopterygids and Planaeschnids, several other interesting dragonflies. Rhinagrion hainanense is always a great find. Regular at Xuan Son from early spring until autumn, but a wonderful insect. I was also surprised to see a female Merogomphus pavici ovipositing. I had no idea this species flies this late in the year. And two males Lamelligomphus formosanus were another surprise. Of course some Lamelligomphus fly relatively late in the year, but I had not seen L. formosans this late. Boyeria karubei was common, but it is a fine species and a specialty of the park. I also took a few photos of Coeliccia. No less than 6 species were present: C. scutellum, C. pyriformis, C. cyanomelas, C. uenoi, C. sasamotoi and C. poungyi.

Old male Lamelligomphus formosanus, its venter covered in mites.

Pretty Rhinagrion hainanense, male

Female Boyeria karubei

Female Merogomphus pavici, resting after release

Merogomphus pavici, female face

Closer in-hand view. Note the massive hind legs and the spines on it.

Coeliccia poungyi, one of about 12 males

Male Coeliccia sasamotoi

Female Boyeria karubei and Orthetrum glaucum

Saturday at Xuan Son brought me two females that I want to introduce here. Boyeria karubei was present like last weekend, swarming in the evening by the bridge and during the day with several females ovipositing left and right. This female was caught temporarily at the bridge before released again. It is very much like the male in pattern, but of course the abdomen is not constricted at S3.

Boyeria karubei, female, a very large dragonfly

The other female of note was Orthetrum glaucum. It is interesting in that it has a basically unmarked dorsum to the synthorax, but two clear whitish lines on the flanks. This makes it easy to distinguish from female O. pruinosum, which is basically unmarked, and O. luzonicum, which has a marked dorsum.

Orthetrum glaucum, female

The same female at a slightly different angle

Planaeschna guentherpetersi and female of Boyeria karubei

* Post updated November 15, 2025. Planaeschna is synonymized with Aeschnophlebia. Also, Kompier et al. (2021) treated the Vietnamese species of this genus in detail. Below text is adjusted between square brackets [] where relevant.

Sasamoto et al. described a new species of Planaeschna [= Aeschnophlebia] from Xuan Son National Park in 2013, collected, as far as I know, by Do Manh Cuong. After my record of Boyeria karubei during my first visit, I was lucky enough now during my second visit to see several females of this Planaeschna at the same stream as where the original type specimen had been collected. Females were ovipositing on the trees along the stream and on softer vegetation. It is a rather large species, with striking pattern and rather plain face. One female flew up into a nearby bush and allowed for a nice record shot.

Planaeschna guentherpetersi, female [It later became apparent that this particular specimen was not A. ishigakiana guentherpetersi, but a closely related undescribed species, treated in Kompier et al. (2021) as A. sp. 2.

Same female in hand

Along the nearby larger streams I also bumped into females of Boyeria karubei, both in the primary forest and along the stream near the dam, where they were ovipositing on mossy rocks. One could be photographed while hanging inside a bush.

Boyeria karubei, female, with pattern very much like male, but abdomen not constricted at S3

Boyeria karubei, new to Vietnam

In the previous posting I introduced the first record for Vietnam of Boyeria karubei. When studying the specimen, the venation, with crossveins in the median space, RI3 unforked and with a single row of cells between IR3 and Rspl soon made clear it could not be Planaeschna. These characteristics pointed to the subfamily Gomphaeschnini of the Aeshnidae. From there it was a small step to Boyeria. There are 7 or 8 species in this genus, besides B. karubei, described from Laos, B. maclachlani and B. sinensis occur in East Asia. Two species are confined to North America and two to Europe. Boyeria jamjari, described by Jung in 2011 is very similar to B. karubei, maybe with more contrast, as it seems to have reddish bands on the abdominal segments, more contrast in the face and possibly the appendages are more rounded and the epiproct less concave, but this I judged from photos and is highly inconclusive as evidence. If this is the same species as B. karubei, that is the senior synonym. All aspects of the Xuan Son specimens sit very well with the description by Yokoi, measurements, penile organ, appendages and all. Only the antealar carina is not yellow, but yellowish brown and the number of antenodal and postnodal crossveins is less. See below the details and some close-ups of the penile organ.

Specimen 1 nodal index 22-25:23-21/22-19:18-22 TL 84 mm, ABD (incl app) 64 mm, HW 53 mm.
Specimen 2 nodal index 20-29:28-20/22-18:19-21 TL 82 mm, ABD (incl app) 62 mm, HW 52 mm.

Penile organ last segments, ventro-lateral

And lateral view

An eventful day in Xuan Son National Park and surroundings

Saturday October 12 we visited Xuan Son NP. More about this is to follow soon. We had some great birds and some fantastic dragonflies, but for now let me post two biggies. The first was caught when on a dirt road parallel to Road 32, while circumventing the park, I noticed a gomphid by the roadside. It turned out to be a lamelligomphus, without humps on S8 or dorsal tooth on the superior appendages, so I was thrilled to have found another of the enigma Lamelligomphids. But close inspection at home showed that even if it was not L. camelus, it also was not the species caught before at Tam Dao! A third species! Here a few photos. The specimen keys out as L. hainanensis, especially due to the absence of a thumb like process on the anterior hamulus. But there is something else intriguing about this specimen and that is that the dorsal stripes are connected to the collar, something to my knowledge never seen in the genus. The appendages by the way are also different from my other enigma species, without the teeth on the inside, shorter inferiors, not projecting clearly beyond the superiors and without the leaflike tip.

And while at dusk at a bridge in the park, all of a sudden 15 or so large Aeshnids started swarming under it. At first I thought these might be the recently described Planaeschna guenterpetersi and who read this entry in its first version will have seen the species tentatively identified as Planaeschna sp. But in fact appendages and coloration are quite different. A day spent in the books led to the conclusion that this was in fact Boyeria karubei, a species described by Yokoi in 2002 for Laos. A first record of this genus in Vietnam. I will explain a little more on its ID in a new entry.

All suggestions on the Lamelligomphus are welcome!

Lamelligomphus sp., male

Compare shape of tip of appendages with the enigma Lamelligomphus

Same

Note lack of teeth on the inside of he superiors and no extension of the inferiors away from the superiors

This is weird, collar and dorsal stripes connected

Facial pattern with split yellow line over frons

Comparison with previous enigma, note differences in appendages

Penile organ of present specimen, divergent

Enigma specimen, very different

Scan of the Boyeria karubei, male

Boyeria karubei, male, note brownish face, but also extensive singular markings on the abdominal segments and all green eyes

S10 and appendages in lateral view

In dorsal view, not concave shape of epiproct

And the same in ventral view

A very reddish-brown face indeed