Jewels of forest streams!

Xuan Son National Park is a great place for Calopterygids. October 26 was as good as expected, with many Matrona basilaris, Matrona taoi and Atrocaloperyx coomani. I decided to take pictures of the females. These are all similar in that they have large whitish pterostigmata, but when you know them they are not difficult to identify. Matrona taoi is decidedly reddish brown, which is especially conspicuous in flight. Matrona basilaris is brownish, but if it opens its wings these are dark brown with milky bases, in a pattern similar to the male. Atrocalopteryx coomani has hyaline wing bases.

Female Matrona taoi, with its typical reddish brown wings

Matrona basilaris female with brown wings

And female Atrocalopteryx coomani, showing translucent wings

A few interesting Calopterygids from Bac Kan and Cao Bang Provinces

I know this stream along the TL257 in Bac Kan, at Km 58, that has some really interesting Gomphids in spring. So on August 30 I paid it a visit. And not in vain. The price of the day went to Matrona taoi, a rare endemic Matrona species, recently described from Xuan Son and apparently also known from Quang Binh Province in Central Vietnam. It may be more widespread. The stream I visited is not special, running along a clearing with cultivated fields and degraded forest on one side. It is not particularly wide either, 2 meters or less in most places. But along the stretch of about 400m I counted 4 males of this wonderful species. A few Matrona basilaris were also present, and many Vestalis gracilis.

The next day along the TL212 in Cao Bang I visited a small stream by the road side in a pocket of rice fields and houses. This stream also seems like nothing special, but it had 4-5 males of Atrocalopteryx coomani. This is a relatively widespread, but definitely scarce species. In Pia Oac I found another Matrona basilaris. Clearly the advent of autumn is bringing other species!

Male Matrona taoi, a beautiful and rare damsel

Showing the wing pattern, with lighter outer thirds

Scan of male Atrocalopteryx coomani, with also a very interesting wing pattern

Which is not visible in the perched insect, apart from the short moments it will flash its wings

December 8, Xuan Son in the winter sun

This Sunday, I drove to Xuan Son, to see what has changed since I last visited. Like in Huu Lien, water level had dropped, but the good streams were still good. Here too about 30 species for the day, but numbers for most were down. Coeliccia sasamotoi was the exception, being very much in evidence all over the place. What is interesting is that several species recorded for Huu Lien in summer, but completely absent during all our visits this November / December were still commonly flying at Xuan Son. Aristocypha fenestrella and Matrona basilaris were easily found. Also Euphaea masoni, only seen during our first visit to Huu Lien a month ago and not since, was still about in small numbers. What makes them stay on here?

I bumped into the following species: Matrona basilaris, M. taoi, Vestalis gracilis, Neurobasis chinensis, Atrocalopteryx coomani, Vestalaria miao, Noguchiphaea yoshikoae, Heliocypha perforata, Aristocypha fenestrella, R. "arguta" (I took pictures of several in hand, with hardly any orange on S9-10 to quite a bit), Euphaea masoni, Agriocnemis femina, Ceriagrion auranticum, C. fallax, Pseudagrion pruinosum, Coeliccia onoi, C. scutellum, C. sasamotoi, Indocnemis orang, Copera marginipes, C. vittata (I must have overlooked it before), Boyeria karubei, Orthetrum sabina, O. pruinosum, O. glaucum, Diplacodes trivialis, Neurothemis fulvia, Palpopleura sexmaculata, Crocothemis servilia, Trithemis festiva, T. aurora.

Old male Euphaea masoni

Another male with hole in wing

Matrona basilaris, male, was still common

Matrona basilaris, female

Atrocalopteryx coomani, male

Matrona taoi, male, only one and damaged male around

Pretty Coeliccia sasamotoi, male

Ceriagrion fallax, male

One of several captured Rhinocypha cf. arguta, with at least some orange on S9-10.

Very nice male Copera vittata, overlooked previously?

Matrona taoi revisited

This Saturday we visited Xuan Son National Park once more, to look for a few more goodies. Matrona taoi was encountered repeatedly, although in small numbers. We could observe a few females too, one of which was ovipositing on floating and submerged plant material while a male was either dancing nearby, or sitting close by signaling with its wings. The female has the white pterostigma also seen in the females of M. basilaris and Calopteryx coomani, but the wings are reddish brown as in the male and do not have translucent areas or lighter bases.

Matrona taoi, female

The male of Matrona taoi

Displaying to the female ovipositing nearby (or to potential competitors?), by opening and closing of the wings and raising the abdomen

Tidying up the last bits of Xuan Son

Just before the weekend starts with new adventures time to tidy up the remainder of records from Xuan Son. I will start with another new species for me, Vestalaria miao. And to be honest, I cannot be a 100% sure of the ID. Noguchiphaea yoshikoae occurs also in the area, but has characteristic horns on the prothorax, not present in Vestelaria. And Vestalaria miao was recorded right there in Xuan Son, but who knows, maybe another species is present too. So the search for more evidence continues. Here she is:

Vestalaria miao, female, with slightly tinted wings

The same female in hand, note the absence of horns on the posterior lobe of the prothorax

For comparison female Noguchiphaea yoshikoae of Tam Dao in September, very similar although wings slightly different in shape and clear, eyes of different color

Note the horns on the posterior lobe of the prothorax

The second species to publish here is Cratilla lineata, of which I encountered a female in the rain. Cool as addition to the earlier male. She is very similar in markings, but of course with a differently shaped abdomen.

Cratilla lineata, female

What else was worth to mention? How about a teneral male Pseudagrion pruinosum? Here he is, as a possible stumbling block for the unwary.

Pseudagrion pruinosum, immature male. The appendages are a give-away. The neck looks rather bull-like, due to a rain drop that has lodged itself there.

Close-up of the neck and the rain drop. Soon after it would remove it by brushing.

The last to enter for today was an array of Calopteryds. The first is Calopteryx coomani, a species I have seen regualrly at Tam Dao National Park and that also frequents Xuan Son. Especially the female is superficially similar to the female of Matrona basilaris, but that species has, just like the male, a milky shine to the bases of the wings due to the fine maze of veins there, absent in C. coomani. Both are large species, but C. coomani is even more robust.

Atrocalopteryx coomani, male, with blueish shine to abdomen and visibly here translucent areas in the wings.

Male showing the largely translucent front wings and bases to the hind wings.

Atrocalopteryx coomani, female

Matrona basilaris was already introduced in an another entry, but not the female. Compare here to the female of Atrocalopteryx coomani, to which it is rather similar when perched and the milky bases to the wings are not visible. The color of the wings is more greenish and the wings are more slender.

Matrona basilaris, female. I saved this one from the water, where it had become entangled in cobwebs when ovipositing. It did not linger when I released it and perched far away, which explains the grainy picture.

Matrona basilaris, male, for completeness sake

And finally, because it is such a special species, another Matrona taoi male. I find this species much more like A. coomani than like M. basilaris, when it comes to size and shape of the wings.

Matrona taoi, male

Xuan Son outing, other records

The visit to Xuan Son was intended to search for some late season stream species. As we approached the National Park from the east and not from the north, we ended up at the wrong entrance. Wrong, because we could not find some essential streams in primary forest. Nevertheless we had quite a good time, but convinced we were in the wrong place we decided to try to approach from a different direction. Quite a challenge without a detailed map of the area and none of the villages mentioned. But we were successful in that we made it late in the afternoon to Lap Village. That was a fantastic place. The trial and error driving around route 32 brought us the already mentioned Lamelligomphus sp. and a Lesser Emperor, Anax parthenope junius. This is a species recorded as a vagrant from Vietnam, but it is likely it is more common. We saw a male over a pond by the road side, but it did not allow pictures. However, its small size, brownish abdomen with extensive light markings pointed away from A. guttatus and to this species. I guess we need a little more definite proof next time. In Lap Village one of the last dragonflies of the day was a smashing Matrona taoi, described from Xuan Son only two years ago. And because we were so late we sat a bit on a bridge at dusk before returning to Hanoi (a three and a half hour drive after all), when all of a sudden in the last light of the day the already mentioned Boyeria karubei started swarming. Not at all a bad October day, with 35 Odonate species. Besides the aforementioned goodies Onychothemis testacea also still put in an appearance. Below some of the stream damsels for which this is such a good area.

Matrona basilaris, male. We only saw one, but it is still early in the season

There were already quite a few Vestalis gracilis about, here a male

And here a teneral male. We saw several freshly emerged.

Copula of Vestalis gracilis

One of the targets: Matrona taoi, male, in all its splendor

Pretty Neurobasis chinensis, here the male, was common

Neurobasis chinensis, female

Euphaea decorata, female

Euphaea masoni, couple side by side

Heliocypha perforata, male. One of at least 5 species occurring in the area, of which we saw also R. biforata and Aristocypha fenestrella.