It's a male's world (but it would be nothing without females)

Hanging around Pia Oac on April 4 and 5 I bumped into several interesting females that I would like to share here. Plus one interesting copula.

This here is the female of Mnais andersoni, by virtue of its association with a bundle of males

This is a copula of Ischnura carpentieri. The andromorph female it not common at all

Female Trithemis festiva, much more difficult to find than the male

Ovipositing female Anax nigrofasciatus

A different female A. nigrofasciatus, caught hunting over the road on the mountain

Female of Orthetrum triangulare with less clearly marked thorax compared to O. glaucum and dark tip to abdomen

Ceriagrion species of early April in Pia Oac

4 and 5 April I visited Pia Oac and surroundings. Ceriagrion fallax is a common species here and was already abundant around ponds. But I was thrilled to also find Ceriagrion chaoi, a species I had previously seen only at Xuan Son. And not only did I see it at the "Trigomphus carus" pond on the slopes of Pia Oac, I also saw it at the weak bridge 10km to the south. Clearly it is not rare in the area. I saw C. auranticum there too, only one male, but more thrilling, because it is less common, even scarce, and extremely beautiful, I saw a great many C. azureum. One could almost say it was abundant on the flooding rice fields. Here are some impressions of all but C. auranticum.

To start with a copula of C. azureum

A male, this specimen with some spots on the thorax, likely some kind of damage.

And the greenish female of C. azureum

Copula of Ceriagrion chaoi. Note the yellowish-green eyes and dark dorsum of S9-10 in the male.

Another male C. chaoi

And finally, common but pretty Ceriagrion fallax

Trigomphus carus - a new species for Vietnam

Saturday April 4 it was an absolutely lovely day and I woke up very early for birdwatching in Pia Oac. When the sun became hot I went to a lower area on the mountain and checked also some streams and a small pool by the roadside. It was here around noon that I noticed a small gomphid perched on a blade of grass over the pool. I was taken aback by it. From a distance its pattern reminded me of Davidius species, but after a quick photo I was able to catch it and in hand quickly concluded it was a Trigomphus species. Only a few minutes after I had taken it another landed on exactly the same blade of grass. Because these are difficult and variable species and because it was a new species to Vietnam for sure, I took this male as well.

There are 14 known species of Trigomphus, although the true number may be smaller, with several synonyms in use. (The 14th is the new species from Vietnam I found last year, which will be described by Karube in an article to be published in May this year*). The particular thorax pattern, shape of appendages and of the genitalia all fit very well Trigomphus carus, a species only known from Fujian in China, as far as I can tell.

This species has the dorsum of the thorax marked by thin "7" shaped stripes and a small antehumeral spot. In fact as is often the case, this character is somewhat variable. One specimen has it, the other does not. Also there is some variation in the lateral thorax pattern. Shape of posterior hamulus is rather distinctive for T. carus and also the somewhat triangular outline of the anterior hamulus is indicative. The inferior appendages, interestingly, curve outward slightly, whereas in most species they curve inward. The match in appendages, anterior and posterior hamulus and penile organ, plus the close match in pattern of the thorax and size (one specimen has abdomen 37 and HM 30mm, the other 36 and HW 29mm), makes identification as Trigomphus carus possible.

* Described as Trigomphus kompieri in the May 2015 issue of Tombo

Trigomphus carus male as found, perched on a leaf 40cm above the water of a small pons

The same male, in hand. Note the anal triangle with 5 cells.

Both males scanned in dorsal view. Note the absence of the antehumeral spots in the top individual, which shows the sometimes limited use as an identification feature.

Both males in lateral view. The bottom individual with slightly less black on the sides of the thorax.

The face of Trigomphus carus, with all-black labrum.

Appendages in dorsal view. Note the lateral process at two-fifths.

Close-up of the right superior appendage in dorsal view.

Lateral view of the appendages. Left side and right side not exactly the same.

Inferior appendages in ventral view. Characteristically slightly curved outwards. The orange bit is poop.

The ventral view of the hamuli. Note the bulging swollen posterior hamuli adorned with a crest-like inward-facing hook.

And lateral view of the hamuli. Here the "hollowed out" triangular anterior hamulus is essential.

March 28, first trip to Xuan Son of the season

The weather forecast said that west of Hanoi might be sunny in the afternoon, so I decided to drive to Xuan Son today. As is often the case, the forecast was wrong, so a cloudy day. Nevertheless I encountered at least some goodies, although nothing unexpected. Euphaea masoni was already very common and E. guerini was out and about too. In the damselfly department Mnais mneme was common too, and I saw the first Pseudagrion pruinosum of the season. Orolestes selysi was also present in decent numbers at the "Gynacantha puddle".
I was really hoping to see Nihonogomphus schorri, which had been omnipresent in April last year. Cloudy circumstances made it impossible to judge whether it is already common in March, but I saw one male briefly. A first female Macromia flew by. Could not verify the species though, shame. And at the "Gynacantha puddle" a few Cratilla lineata and quite a few adult or semi-adult Gynacantha subinterrupta were huddled in the bushes. All in all not at all bad, given the time of the year and the weather.

Not the best of photos, but anyway, Nihonogomphus schorri, as soon as the sun showed itself, no matter how short.

Female Rhinocypha perforata, quite common

And the male of Rhinocypha perforata. See the lateral thorax pattern. It is the same as in the female, although the forum is very different.

Neurobasis chinensis is a common damsel, but also very pretty, especially when it displays the top side of the hindwing.

The female of Neurobasis chinensis, with the typical double white dot.

Euphaea masoni already very common. This specimen kind enough to keep its wings open, displaying the typical translucent base and tip in the forewing and the reddish brown luster to the inside of the wings.

But the outside is dark blueish

Mnais mneme male, this one already pruinose on the thorax, a feature missing in Mnais andersoni.

The female of Mnais mneme, specimen with reddish veins

Immature (and already missing a pair of legs) Mnais mneme. When there is no pruinosity on the thorax it can be separated from Mnais andersoni through the structure of the penile organ.

Gynacantha subinterrupta with its typical abdominal pattern of oblique light bands. This individual almost adult, but the thorax still not fully green and the face still whitish.

Face of the same individual, showing cream white, not yet yellow.

Different male, this one with yellow face and green thorax, fully mature

Flashback - trip to Cat Tien NP 6-9 February 2015

In early February we spent a few days in Cat Tien National Park. It was very dry. Not a drop of water in the forest - virtually. But the fishponds were still productive and the odd stream or trickle also provided some species, but everywhere in low numbers. Clearly middle of the dry season is not the best time for Odonata here. Consequently we did not find anything new for the park list. But some species were very present and one was Gynacantha basiguttata, of which we saw several along the road through the forest, now adults.

Another species that I had seen only once, and that previously eluded photographic capture, was Rhyothemis triangularis. I was able to take pictures of a freshly emerged specimen.

And lastly, one evening, as I was heading back to the lodge, I ran into a roost of Potamarcha congener. An exceptional spectacle!

Gynacantha basiguttata female, now fully mature. Note the dark smudges at the base of the wing along the subcosta.

The face of the same female

A little extra: male Agriocnemis nana. I saw only a few, but what a delight.

Roost of Potamarcha congener. How many in the photo? I count at least 50.

Fresh male Rhyothemis triangularis, the only one seen.

First visit to Huu Lien in 2015 - Trigomphus* **

*This entry was adjusted slightly after publication of the description of Trigomphus kompieri Karube, 2015
**And again after publication of Paracercion ambiguum Kompier & Yu, 2016

Sunday March 22 was supposed to become a sunny day. Sadly, the weather forecast is not very reliable in Vietnam, but after a very cloudy morning I did have some weak sunshine in the afternoon, just enough for things to become a little more active. Last year in April I had found a new species of Trigomphus in Huu Lien, but by then it was already scarce, as Trigomphus is an early genus (season-wise). I wanted to take some better photos of it, so for the first real dragonfly trip in northern Vietnam of the season I headed for Huu Lien. In the morning I saw two males and a female, but they did not linger. When the sun came out in the afternoon they showed better, but sadly no female anymore. This Trigomphus species is the most southerly (apparently) of the genus and with the broad dark line of the flanks quite exceptional. A lovely gomphid. It has recently been described by Haruki Karube as T. kompieri.

I was able to see 31 species over the day, not bad, given that the weather was not good and it is only March. Highlights included 5 freshly emerged Asiagomphus, likely A. auricolor, 3 Epophthalmia elegans, Anax guttatus, and Paracercion ambiguum.

Beautiful Trigomphus kompieri, male

Another male perched by the side of the stream

Same male as in the previous photo, perched this time on a snag 

A common species, but handsome, Trithemis aurora, female

Copula of Pseudagrion microcephalum, one of three Pseudagrion species observed today

Already subject of the blog on many occasions, yet another photo of the pretty Paracercion ambiguum.

One of five freshly emerged Asiagomphus, likely auricolor.

A great start of the year

2015 has been very warm in the first few months, so while birding I kept running into unexpected dragons and damsels. But we have been very busy on the field guide project for REGUA, so I have been slow on getting back to the blog. But now it is the middle of March and soon the streams will explode. This weekend Kameliya and I visited Pia Oac for birds and had a great time. But the afternoon of Sunday was sunny and besides almost 300 migrating raptors also enticed several Odonata to venture out. Apart from Pantala flavescens, Palpopleura sexmaculata, Orthetrum pruinosum and O. japonicum internum, plus Ceriagrion fallax and Anax nigrofasciatus, there were quite a few Mnais about. At home the penile organ helped ascertain the species: Mnais andersoni. Although M. mneme becomes pruinose on the thorax whereas this species does not, in early spring M. mneme too is still lacking pruinosity. That is when the penile organ comes in handy (see earlier blog entries).

Male Mnais andersoni