Saturday, 30 November 2013

A visit to Van Long - look what the cat brought in

So, what did I see at Van Long? The most interesting record was of a female Mortonagrion aborense. Now I have seen this species at Van Long, at Cuc Phuong, in Huu Lien and in downtown Hanoi. Clearly it is in fact a common species in northern Vietnam that has been very much overlooked until Sebastien ran into it.

Mortonagrion aborense, female
I also took a pretty good shot of Pseudagrion australasiae, a male. There were not many around. I saw maybe 5-6 males over the day.

Pseudagrion australasiae, male. Note the short superior appendages, half the length of S10. Otherwise very similar to P. microcephalum.
And the last species that deserves a bit of attention was Ceriagrion auranticum. There were quite a few flying and this female did me the courtesy of staying put. Note the long abdomen, protruding further beyond the wingtip than in C. nipponicum.

Ceriagrion auranticum, female, with wings up to 1/3 of S6

For convenience, the female C. nipponicum of a few posts back:

Ceriagrion nipponicum, female
And of course that other Paracercion, P. calamorum. There were still several around, including some females.

Paracercion calamorum, male

Paracercion calamorum, female

A quick visit to Van Long - The Paracercion problem*

The last several days I have been very busy with work on the one side and haunted by the Pseudagrion enigma on the other. Rory Dow suggested to look into the possibility of it being related to Paracercion impar and that is why I looked into the Paracercion article by Dumont (thank you Rory) and at the same time decided to take a closer look at the posterior view of the few specimens of Paracercion I have to see what it looks like in real life, compared to the drawings of Dumont. What a shock to find that the posterior view of the specimen from Van Long and that from Huu Lien, very similar in lateral and dorsal view, are completely different! See below first the lateral views:

The Huu Lien Paracercion species

The Van Long Paracercion species, yes there seem to be some slight differences I overlooked

But the posterior views are really revealing:

The Huu Lien specimen

The Van Long specimen
So quite a shock to find that these must to two different species, but very similar in other aspects. I work under the assumption now that the Huu Lien specimen is P. melanotum, whereas the Van Long specimen likely is (Para)Cercion malayanum.

Anyway, this is why today I drove to Van Long, to see if I could obtain a few more specimen of "malayanum". This proved difficult, as there was really not a lot going on at Van Long, even if the weather was pretty good, sunny, 22 degrees. Hardly a damsel or dragon was moving. It is strange how different the mountains in the north are compared to the Red River Deltaic area. I did see a few things of interest though, and I did collect two more males. Hopefully there will be success at Huu Lien too, tomorrow.*

* Note that I found the female of P. melanotum in Huu Lien (see the post on that subject), but I also took photos of the posterior view of the appendages of the Van Long new specimens after this post, that throw a different light on the subject. See the post: "Paracercion continued."

Here is a photo of a male perched on a floating leaf.

Paracercion cf. melanotum (explained in post "Paracercion continued"), male 

Thursday, 28 November 2013

Polycanthagyna erythromelas

I am reaching the end of species that I have not published on the blog yet, but there are a few more to go. One is Polycanthagyna erythromelas, an aeshnid that is not rare, seemingly, but I have not seen it often. In fact I had only a few females flying by through the months, for instance at Tay Thien, Tam Dao National Park and once a male hanging in a tree over a small pond in a rocky stream on a hill side in Ba Be National Park in early August. I could take a few distant shots before it dropped of its perch and darted off to new and unknown adventures. This is it:

Polycanthagyna erythromelas, male

Wednesday, 27 November 2013

Potamarcha congener

One common dragonfly I have not yet discussed is Potamarcha congener. This is an interesting widespread species of which for once the females are very often encountered. This is because they have the habit of perching on wires in the open. Males you hardly ever see on wires. Come to think of it, I do not recall such instance, but that seems odd. Anyway, males you see at ponds, where they perch over the water on twigs, or nearby in fields on bushes. The male is a larger, paler version in some ways of Trithemis festiva, whereas the female has an interesting thoracic pattern of 4 pale lines. It also has the flanges on S8 of Orthetrum females. I have seen P. congener all over northern Vietnam and also in the Mekong Delta, although it is nowhere abundant.

Potamarcha congener, female, for once not perched on a wire (involuntarily)

Potamarcha congener, male

Another male, more pruinose on the abdomen

Sunday, 24 November 2013

The Huu Lien list, until now

After last weekend and this Saturday, an update on the list for Huu Lien National Park. Sebastien mentioned his sightings also on his blog. It is good to compare our sightings with the list published for visits in June by Cuong & Toan. There are some striking differences. Marked with * not on Cuong et al. My list for now is 50 species long, but we are just scratching the surface, that much is clear and it is late November, after all.

Atrocalopteryx atrocyana, *Atrocalopterix sp. n., Neurabasis chinensis, Vestalaria miao, Vestalis gracilis, Libellago lineata, Rhinocypha biforata, R. perforata, R. cf. drusilla group ("huai"), Euphaea masoni, Ischnura senegalensis, Agriocnemis femina, A. pygmaea, *Ceriagrion auranticum, *C. nipponicum, *Mortonagrion aborense, *Paracercion melanotum, *P. calamorum, *Pseudagrion microcephalum, *P. rubriceps, P. pruinosum, *Pseudagrion sp. n., Coeliccia sp. n., Copera ciliata, C. marginipes, C. vittata, Prodasineura autumnalis, *Anax guttatus, Gynacantha saltatrix, *G. subinterrupta, *Ictinogomphus pertinax, *Labrogomphus torvus, Paragomphus capricornis, Crocothemis servilia, Orthetrum sabina, O. pruinosum, O. glaucum, Pantala flavescens, Trithemis aurora, T. festiva, *T. pallidinervis, Brachythemis contaminata, Diplacodes trivialis, *Neurothemis fulvia, Onychothemis testacea, Palpopleura sexmaculata, *Potamarcha congener, *Rodothemis rufa, Rhyothemis variagata, *Tramea virginia, Zygonix iris.

That is a whopping 18 different species in my list. 

A few more common dragonflies not yet on the blog - Trithemis

There are two (very common) and one less common, but certainly not uncommon, Trithemis species easily encountered in northern Vietnam. One is the very purple Trithemis aurora, a common, but excitingly beautiful dragonfly. There are after all many reddish, but few purple dragonflies about. The second is the dark blue (but with abdomen checkered with yellow) Trithemis festiva, a species occurring as far west as Turkey. And lastly, the somewhat different Trithemis pallidinervis, which sits with wings raised very much like the Idiataphe dragonflies of the New World. There is some difference in the way these different species from the same genus behave. T. aurora males sit often on exposed branches and twigs sticking out of, or overhanging the water. T. festiva likes to sit on rocks or concrete along or in streams and T. pallidinervis is a species not of streaming, but of standing water, and sits on emergents in heavily vegetated shallow waters. It is for instance common in Van Long, but I also saw it in Huu Lien recently. T. aurora females are easily found perched on the tips of branches, often quite high, from where they hunt, T. pallidinervis females can be found perched in the same way as males along lakes and pools, but females of T. festiva are rarely seen, at least by me. T. pallidinervis was introduced before, but for completeness sake, here an old specimen (in fact from Huu Lien)

As purple as it gets, Trithemis aurora, male

A different male

Trithemis aurora female, not a good photo, I know, just did not get round to taking proper pictures of it

Trithemis festiva, male, on a rocky surface

Trithemis pallidinervis, male, and a nice oldish one too

Saturday, 23 November 2013

The Cuc Phuong Coeliccia sp. n. also at Huu Lien*

When checking a little stream by the side of a field in Huu Lien, we bumped into 3 males of the pretty little Coeliccia still to be described from Cuc Phuong. It is good to know this species is more widespread. Here is a record shot.

* Sebastien pointed out that although I call it the Coeliccia from Cuc Phuong, because we saw so many there, it was in fact first found at Huu Lien and only later at Cuc Phuong. So I did a little bit of reverse engineering here.

Undescribed Coeliccia male

Additional Ceriagrion and Paracercion photos*

*Adjusted after publication of Paracercion ambiguum

With another visit to Huu Lien, I had to try to get additional pictures of both Ceriagrion nipponicum and the possible new Paracercion species. Both were around at the reservoir. I could collect two more males Paracercion and C. nipponicum posed well enough. It was fun watching them battle with C. auranticum, showing the striking color difference.

Ceriagrion nipponicum, male

Another male, equally vivid
Let's throw in Ceriagrion auranticum for comparison, a male
And Ceriagrion nipponicum female, note the relative short abdomen (wings reaching 3/4 of S6)

The enigma Paracercion, all characteristics proved consistent

Gynacantha subinterrupta and G. japonica

Saturday 23 November was a misty and cloudy cool day, but evens, we headed to Huu Lien for another eventful day. Saw some good birds too, but this is about dragons. In the late afternoon we saw several light brownish colored Gynacanthas flying about in very erratic fashion. Because of the checkered appearance of the abdomen G. subinterrupta? And yes, eventually I was able to net both an immature male and immature female. Compare them to the fully mature male from Ba Be in July and the difference in coloration is very obvious. The checkered appearance of the abdomen remains striking. There were also a few Gynacanthas with more direct and straight flight paths towards dusk. I could catch one, indeed, female G. japonica. Here are the photos.

Gynacantha japonica, female

Gynacantha subinterrupta, immature male

Gynacantha subinterrupta, immature female

Friday, 22 November 2013

A few cool jewels from Huu Lien

We encountered 4 species of Jewel at Huu Lien, Heliocypha perforata, Rhinocypha biforata, aforementioned Rhinocypha cf. drusilla group and Libellago lineata. These are lovely damsels, brilliantly colored, and especially Libellago, tiny. All were very common in places, apart from the drusilla type, of which we saw only one. Here are a few impressions.

Beautiful Rhinocypha biforata, male
Rhinocypha biforata, female

Stunning Libellago lineata, male

An immature male Libellago lineata

And the female Libellago lineata

Heliocypha perforata, male

Paracercion malayanum, more widespread?*

On Sunday 17 november we spotted a single male Paracercion malayanum* at a stream in Huu Lien National Park. This is interesting, as so far as I know this species is in Vietnam only known from Van Long Nature Reserve, several hundred kilometers away. It is very common there, but here as said we only observed one male. There were many Paracercion calamorum about, a species it also occurs side by side with at Van Long. Anyway, likely it has a wider range in Vietnam than thought until now. That in itself is not strange, clearly there is still much to discover. In fact, every weekend we run into new records, range extensions and new species.

* See also the later post on Paracercion, especially "Paracercion continued", as this post is outdated and the species at Huu Lien is not Paracercion malayanum, but P. melanotum

Paracercion malayanum, male*

The same male, in hand.

Thursday, 21 November 2013

Macrogomphus rivularis, maybe - but no, Labrogomphus**

Martin in 1904 described a large Hagenius species, now put in the genus Sieboldius. The description has no plates and is of a male, found in Tonkin. Do Manh Cuong et al. described males from Cuc Phuong and also recorded it from Huu Lien. We observed several very large aeschnid-like dragonflies that turned out to be female Gomphids looking for places to oviposit along a moderately large stream in open country close to a forested karst mountain. I could take a few shots with the telephoto lens, but with my new camera and all that, the settings were wrong. However, what can still be seen is the double yellow band at the base of S7. So, I concluded these were likely Sieboldius gigas. But I consequently found out the Cuc Phuong record was later ratified, in fact it is Megalogomphus sommeri, and checking other records of that species, that seems a better match! I am sure we will run into it for better shots next time. It was interesting to see gomphids this late in the season. Of course Ictinogomphus pertinax, but also Paragomphus capricornis was still around.

*Matti Hamalainen sent me a photo of female Megalogomphus sommeri and pointed out that the shape of the abdomen was not consistent with that species. I have to concur. He also suggested it might be the rare Macrogomphus rivularis and yes, the long S9 seems to suggest that genus. All the more reason to try to relocate it.

** Well, we now know that it is another genus with very long S9, but new to Vietnam, Labrogomphus

Labrogomphus torvus, female

Wednesday, 20 November 2013

At last, Copera vittata! Overlooked?

Yellow-legged Copera are everywhere in Vietnam. We call them geelvoetje, little yellow foot in Dutch. It is always Copera marginipes. The other common Copera is C. ciliata, with white legs and we call that one therefore witvoetje, little white foot. And of course there ought to be another Copera around, with orangy legs, but I never saw it. I did notice that the amount of white on the abdominal tip is rather variable in C. marginipes, but studied enough closely to conclude that it was always this species. In Huu Lien however I once more closely looked at all geelvoetjes and noticed that the appendages looked different on some, even if the legs were yellowish, not orangy. And I also remembered that the dorsum of the thorax was supposed to be blodgy, not sharply demarcated from the humerals. Well, study up close revealed that this was nevertheless C. vittata. Clearly the geographical differences, or individual differences, are great. The appendages however leave no room for doubt, they are very differently shaped from C. marginipes, with longer superiors and upwards slanting and tapering inferiors. It is definitely possible that I had overlooked it in the previous months. From now on I will pay better attention and surely will find out whether or not it is in fact commoner.

Copera vittata, male, note the bushy looking appendages

Another male, with very yellow legs

Yet another male, note the appendages. Yellow legs and dark, clearly demarcated dorsum of thorax

Another male, showing tapering and upward slanting inferior appendages

For comparison, Copera marginipes, note straight and thick inferior and short superior appendages, and interestingly, longer wings, reaching unto S6.

Another Ceriagrion, C. nipponicum, new for Vietnam

When at Huu Lien checking a stream we noticed a Ceriagrion with red abdomen, red face and rufous dorsum to the head and thorax sitting on some grasses growing in the stream. After a few record shots we collected it. The next day we saw several again along a different stream and also about 5 along the grassy verges of a reservoir. Apparently it was not uncommon in the area. It was easily separated from Ceriagrion auranticum, also present, by its slightly smaller size, reddish head and thorax (in fact reddish dorsum and paler ventral side). The appendages are very short. This must be Ceriagrion nipponicum, a species known from Japan and, according to Asahina, from mainland China. The present specimen has very similar appendages and mesostigmal plate to the specimen from Shanghai. I originally thought this might be C. praetermissum, but that species has longer and differently shaped appendages, different mesostigmal plate and is even smaller. This is of course a substantial range extension, but maybe it has been overlooked, as there are quite a few photos on the web of very (too?) red C. praetermissum.

Ceriagrion nipponicum, male

The same male, in hand

The very short appendages, typical of C. nipponicum

Gynacantha japonica - addition to the Vietnamese list

When at Huu Lien last weekend we noticed some Gynacantha flying low over the field nearby a stream and were able to catch one. It appeared to be different from Gynacantha subinterrupta, with light colored epiproct and differently shaped thin cerci. The abdomen also did not have the checkered appearance of subinterrupta, even if the thorax was quite similarly colored. The next evening we saw many more at the same location, hunting for insects low over the grasslands adjacent to the same stream as the evening before. In fact G. saltatrix had been reported from Huu Lien during the survey by Cuong and Toan, so I considered it that species, which is not rare, known from Southern China, Myanmar, Thailand and Vietnam. It has strong likeness to G. japonica, but that species to my knowledge had not been recorded in Vietnam, although it is known from Southern China. I therefore published this originally as G. saltatrix, but as pointed out by Wen Chi Yeh, it is in fact G. japonica, as can be judged from the relative length of epiproct and cerci, with G. japonica displaying much longer cerci.

Gynacantha japonica, male

Slim cerci and light colored epiproct of male in ventral view, cerci over 4 times length of epiproct

Tuesday, 19 November 2013

Another Paracercion enigma from Huu Lien*

*Adjusted after publication of Paracercion ambiguum

On November 16 and 17 I observed several interesting Paracercion specimen that appeared to be different from what I had seen so far, prompting me to collect one and take shots of others. There were at least three Pseudagrion species in the area, P. pruinosum and P. rubriceps, both easy to recognize, and P. microcephalum, now also in my easy book. This however seemed to be P. spencei, but the reader will remember that this species could be recognized by the greenish lower eyes, apart from the long and bifid superior appendages. Now, the species that had me puzzled had blueish eyes. Maybe not as blue as microcephalum, but certainly not greenish. Under the microscope the similarly long, but very differently shaped appendages made it very apparent that this is not spencei. I have no idea what it is, if not that. It looks like a Pseudagrion, but strange within that group as it has two large post ocular spots, which is usual, but these are not connected by a bar in the same color. There it is, another blue Pseudagrion, very similar but different and unknown. I am open to suggestions! It is definitely a new species to Vietnam, but is it known outside Vietnam? (Now we know its true identity: Paracercion ambiguum)

Superficially similar to P. spencei, Paracercion ambiguum male

Another male, see open S2, long appendages, light blue eyes.

Two large post ocular spots, but no occipital bar

Very differently shaped appendages in dorsal view

And in lateral view, with two lobes, but no clear deep incision in superior and upward slanting inferior