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

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

Rhinocypha huai, or rather "Rhinocypha sp. from drusilla group"?

Rhinocypha huai has been described from Hainan by Zhou & Zhou in 2006. Later it was also recorded on the Chinese mainland. This species is very similar to Rhinocypha arguta, described from Thailand in 1997 by Hamalainen & Divasiri (and other species in the drusilla group). Typical R. arguta has all black S9 and S10, whereas huai has extensive orange-red on S9 and also red on S10. Since then R. arguta has also been reported from Vietnam, from Xuan Son National Park. However, the males I observed there had variable, although limited amounts of orange-red on S9 (two separate spots) and S10. Toan and Cuong recorded Rhinocypha huai in June 2010 from Huu Lien. I observed one male on November 16 and took a few record shots. Indeed it has extensive orange on S9 and S10, and restricted black on the other segments. I have not studied the specimen in hand, so cannot say anything on the structural characteristics, but otherwise it is very much like R. arguta. More study is clearly needed. Matti Hamalainen in private communication pointed out to me that both the Xuan Son and Huu Lien specimen have some differences from typical R. arguta and R. huai and are for the time being best treated as Rhinocypha sp. from drusilla group. They are also different from each other, notably in the pattern of S2, and the amount of black on the distal parts of the abdominal segments.

Rhinocypha sp. from drusilla group, male.

Huu Lien, another Holy Grail, meet Atrocalopteryx

Last weekend, November 16 and 17, we went to Huu Lien National Park, after the recent adventures of Sebastien there. It seemed like a good idea at the time and in fact it was! Two days, most of it brilliant sunny autumn weather and 48 species at the end of it. Could not locate a nice stream in the forest, so no Coeliccia, but otherwise it was a big success. Who would have thought, over a month ago we were already telling each other how sad it was, the season over already, but in fact, there is no end to the goodies in places like Huu Lien and Xuan Son.

Like in Xuan Son, the stream inhabiting Calopterids steal the show. We saw Vestalis gracilis, many Vestalaria miao, Neurobasis chinensis, Euphaea masoni, and the best, the two species of Atrocalopteryx.

Although both species could be found along the same streams, there were some striking differences. A. atrocyana was extremely approachable, allowing easy close-up shots and capture for admiring it by hand. On release it would alight on a twig nearby as if nothing happened. We saw only one female and most males under dense cover. On the other hand, the species novum in the area behaved rather differently. Males were often seen in the open, and several females were observed, but all were hard to approach, often flying away when we were still at 4-5 meters distance. Where atrocyana was most abundant they were absent (stream under full cover).

Here are some impressions of both species, brownish species novum and blueish atrocyana. Females were brown, with species novum displaying brilliantly white pseudo-pterostigmata.

Atrocalopteryx atrocyana male, with all green face

Atrocalopteryx atrocyana, female

The same female, displaying all brownish wings

The brilliant Atrocalopteryx atrocyana male, with stunning blue wings in display

The same male, note the hole in the wing. The wings are very broad.

The Atrocalopteryx auco* male, note the white flecks on the face.
* Matti Hamalainen just published this species (2014)

Slightly different exposure showing the color more vividly.

The female Atrocalopteryx auco, note the white pseudo-stigmata

Another male

Devadatta ducatrix

Another species not yet on the blog, until now, is a rather fat, or let's say robust, damsel of small shaded streams in low mountains, which I found both at Ba Vi and Tam Dao National Parks. It is probably widespread across northern Vietnam and quite a nice species, even if drab. It can be hard to spot, sitting close by the ground along trickles in the forest. I have so far only seen males and thanks to the darkness they prefer, not very good pictures of them. So be it, for the time being. I saw them in small numbers between May and August, but not after, even if I visited the habitat where they previously had been present.

Devadatta ducatrix, male at Ba Vi National Park

Another male, this one from Tam Dao

Palpopleura sexmaculata

In the business of tying up loose ends yet another actually really cool little bug, Palpopleura sexmaculata, a common dragonfly of inundated grassy areas. I first encountered it around Ba Vi, but since then in many locations. When they fly around, they are decidedly wasp-like, especially the females, and quite easily overlooked. Luckily they also spend a lot of time perched at the tips of twigs and bushes, but even then their small size and strange dimensions make them relatively hard to spot, until you know them and then you see them everywhere, so to speak.

Palpopleura sexmaculata, female, at the tip of a twig, but not as conspicuous as you might think

And another, taken with flash

And yet another female

And this cool dude is Palpopleura sexmaculata, male