Two interesting females with their males

On April 5 I flushed a fresh damsel from a stream in Cao Bang Province at the foot of Pia Oac Mountain that upon study through my binoculars appeared to be a female of Sinosticta debra, a species I found first for Vietnam last year in Xuan Son National Park. But it flew off before I could take a picture. Luckily on April 18 I saw another female briefly in Xuan Son and this time managed to take a quick ID shot. The same day I also managed some photos of the male. Probably, as this is an early species, the next time I visit they will already have receded in the mists of time.

On April 19, this time in Huu Lien, I saw several Gomphidia abbotti, a not so common, but widespread, species in at least the north of Vietnam. But I also caught a female, something I had not seen previously.

Gomphidia abbotti, male

And Gomphidia abbotti, female

The vulvar lamina of the female

And the final segments in lateral view

Something completely different, elegant Sinosticta debra, male

Undoubtedly as elegant, the female, at least a photo

A new species of Gomphidictinus*

*Adjusted June 1, 2016. This species now published by Karube as Gomphidictinus kompieri. I am really happy with this massive species.

In 1942 Fraser, and right now I do not have the article, so if you have it please send it to me, erected Gomphidictinus for a species in the Gomphidia group with a spine at the base of the apical segment of the penis. Otherwise Gomphidictinus wheeleri, later identified as a junior synonym of G. perakensis, is very much Gomphidia like, although it is very large.

Last year I mentioned a weird Gomphidia from Tam Dao that lived deep in the forest. May 3 I was lucky enough to encounter at least 6 in Xuan Son National Park, all on a stretch of a shallow clear stream under heavy forest cover. I was even more lucky in that I observed 2 females of which I collected one.

Under the microscope the male has the spine of Gomphidictinus, interesting, as G. perakensis is a deep forest species too. It has many differences in color pattern, however, and the female is strikingly different (in G. perakensis S2 is completely yellow, for starters).

It is also a massive insect. Asahina gives abdomen (including appendages) 52-56mm for males G. perakensis, and female 51-52mm. Laidlaw (1902) gives total body length 78mm, already very large. However, my specimens from Xuan Son have the following measurements: Male (2) TL 86-88mm, Abdomen (+app) 64-66mm, HW 57mm, Pterostigma HW 7.5mm. Female (1) TL 90mm, Abdomen 64.5mm, HW 63mm, Pterostigma HW 8mm.
(The Tam Dao specimen was more moderate, with 82mm TL and HW 52mm)

As you can see in the accompanying scan, it dwarfs G. kruegeri, already a large dragonfly. What is further interesting is that it is very pale, not yellow, and that it is very dark. The postclypeus is completely dark, differing from G. perakensis and the female has interestingly a completely unexpected shape to the occipital ridge.

On the left Gomphidia kruegeri, a large dragonfly, and the right the Gomphidictinus species novum, a truly ginormous dragonfly

The male face, with all black postclypeus and labrum

The female face, similar to the male, but note the occipital ridge, quite the opposite of G. perakensis

Note the spine at the base if the apical segment, typical of Gomphidictinus (if a valid genus)

A new species for my Vietnamese list - Gomphidia abbotti

This Saturday at Huu Lien I encountered this smashing large gomphid on two occasions. Identification is quite straightforward, with the double dot on either side on the dorsum of the thorax and the brightly marked orange-yellow and black abdomen. The orange-yellow markings are not always as prominent as in this specimen. Sebastien on his blog mentions the species too, but his sightings are few. He spotted it at Cuc Phuong and in Hoa Binh Province. Hopefully I will have better photos next time.

Gomphidia abbotti abbotti, male

Another enigma, or just another Gomphidia kruegeri?

17 and 18 August I spent happily navigating my way along the streams of Tay Thien in Tam Dao National Park when I noticed a large Gomphid perched along a rocky surface several meters above the stream. This cliff was very wet and dripping, the place deep in the forest. It looked like Gomphidia kruegeri, but the location was very different from the habitat I had encountered that species in in Ba Be. I managed to get a few shots of it, although not very good. The next day, I found another male, on the same stream, but several hundreds of meters removed. This time I could catch it for in hand examination. To my disappointment the appendages looked very much like those of G. kruegeri and as all other Gomphidia are rather different, I dismissed the possibility of it being something else. However, when checking carefully the photos I took at home, a creeping suspicion occurred to me. I had collected this last specimen, so decided to have another look, because on the photos the shape of the antrior lamina seemed different and the pattern on S3 was also quite different. It may well be that G. kruegeri is rather variable, but the differences I noticed do warrant more attention, especially as the individual I took pictures of the previous day displays the same characteristics. For comparison I include also photos of G. kruegeri. The reader can decide if this could be a variation, or something else.

The facial pattern of the Tam Dao specimen

The facial pattern of the Ba Be Gomphidia kruegeri

The first thing here that strikes us is the yellow spot on the labrum of G. kruegeri, which is missing in the specimen from Tam Dao. I have checked the photos published for G. kruegeri on the web for this feature and have only found photos displaying the yellow spot on the labrum. The yellow band on the anteclypeus and on the top of the frons are reduced (and on the frons also differently shaped), and also the yellow spots on the mandibles are greatly reduced. Is this just a very dark specimen?

Superior appendages Tam Dao specimen

Superior appendages of G. kruegeri

What is striking here, is the very straight appearance of the appendages compared to G. kruegeri, but there seems to be ample variation and the same could hold true of the pattern on S10. Intriguing is the length of the appendages in relation to S10 and S8. In the Tam Dao specimen this is (appendages - S10 - S8) 2:1:2.2. In the specimen from Ba Be this is 1.6:1:1.8, thus S10 is considerably larger. This is based on the photos of the complete insects in lateral view.

The Tam Dao specimen

The Ba Be G. kruegeri

What is striking is, apart from the more yellow coloration of G. kruegeri, which although the photos of the other Tam Dao specimen also shows that bleaker ground color, that G. kruegeri has a large yellow triangle at the ventral side of proximal margin of S3, and a dorsal spot, also at the proximal margin of S3. This is consistent in all photos of this species that I could check. Of course, although difficult to assess in this photo, the dorsal stripe is connected to the antehumeral spot to form a '7' , typical of G. kruegeri. The Tam Dao specimen on the other hand misses the basal ventral triangle on S3 and instead has a half ring on the dorsal half of the proximal margin, which is interrupted by the black dorsal carina. This is very interesting. A darker specimen might miss these very consistently present characteristics, okay, but it is not likely that it will then develop an almost opposite pattern.

The genital lobe of the Tam Dao specimen, note also the black ventral side of S3

The genital lobe of  G. kruegeri. 

The genital lobe of G. kruegeri has a characteristic hook at the tip and a round distal profile. There is some variation between the subspecies. The genital lobe of the Tam Dao specimen has a more triangular outline and the hook is absent.

The dorsal pattern of the thorax of the Tam Dao specimen

The dorsal stripe is not connected to the antehumeral spot, as is typically the case in G. kruegeri. In that respect it looks like G. perakensis (from which it differs in many other respects).

Not too sharp photo of another Tam Dao specimen

Another photo of the same specimen as in the previous photo

What can be seen is that the specifics of the collected specimen are also displayed by the specimen in the photograph, although it has seemingly a little larger spot on the mandibles. The labium is all black. Needless to say, there where no other G. kruegeri like specimens not displaying these characteristics about. It also displays the same lighter ground color, robust appendages, dark S3.

Gomphidia kruegeri

This simply enormous gomphid listens to the ultimate gomphid name, Gomphidia. I encountered it on July 23 at Ba Be National Park, but apparently it is rather common. It inhabits larger rapid streams in more open terrain. I am sure it strikes a deep fear in other Odonates. This particular individual had just caught a Vestalis gracilis when it was unlucky enough to be caught itself.

Gomphidia kruegeri, male

A beautiful machine, with a clear weight 

The appendages in lateral view

And secondary genitalia in lateral view