Tramea basilaris - a true vagrant

Today I was hoping to quickly sneak off to the little pool where the last few days the Anax indicus had been hanging around, but it was cloudy all day. Just after lunch the sun seemed to start peeking through the clouds, so I made a dash for it. The pool is only 15 minutes from my place of work. But when I got there the sun was gone again and clouds ruled the sky. But at the side of the pool there was a large branch lying in the water and on one of the tips was a Tramea. It would be out of season for Trames virginia, but it did have rather large saddlebags. However, when I gave it a closer look the lack of an obviously protruding hamule and a hole in the saddlebag soon made it clear this was something else. Indeed, Tramea basilaris. This is an extraordinary species, originating in Africa individuals roam as far as Japan and South America. In Vietnam it is known as a vagrant. At least, that is what the IUCN website says. I had never seen it. So there you have it. At the small pool where a few days ago Anax indicus was discovered as a new species for Vietnam, today yet another rare long distance migrant. The winds have definitely shifted to summer patterns, blowing from the southwest.

Tramea basilaris, showing the genital lobe without a longer hamule.

From behind, showing the irregular saddlebags with paler "hole"

And another side view, showing the saddlebag pattern again.

Some more Tramea transmarina euryale

In August I had already seen Tramea transmarina euryale in Cat Tien. And I had already encountered males in Van Long (Ninh Binh) and in Ba Vi National Park. So, it is widespread in Vietnam. Nevertheless I was happy to see a whole bundle of them ovipositing (females) and patrolling (males) at the swimming pool at Cat Tien National Park Headquarters in November. They were joined by  the larger T. virginia. I had photos of the male before, but not yet of the female.

Female Tramea transmarina euryale. You can see the eggs under the lamina. Upon release she just continued laying. Note the small, somewhat diffuse, basal spot.

The male, much smaller spot than T. virginia, reddish veins.

A few more libellulids from Cat Tien*

*Adjusted on December 28. Tetrathemis platyptera replaced by T. irregularis hyalina.

I saw a few more interesting Libellulids at Cat Tien in early August; interesting as I had not seen them before, or rarely, or in the case of Tetrathemis, was a new record for me.

The first is a small Neurothemis species, N. fluctuans. It differs from the quite a bit larger N. fulvia by the hyaline margin along the posterior edge of the hindwing.

An immature male Neurothemis fluctuans.

The female of Lathrecista asiatica, a common species of the south, although absent in the north. It occurs on pools and puddles in the forest

Immature male Lathrecista asiatica

Male Lathrecista asiatica with red abdomen and pruinose thorax.

Yet another stunning little male dragonfly that was common at the fishponds, Aethriamantha brevipennis. Although Sebastien has recorded it in the north, I have never seen them there and these were my first observations.

Again I apologize for the poor quality of the picture, this one taken with a very much steamed up lens.  It is the female of Tetrathemis irregularis hyalina, which I saw on several occasions on forested ponds.

Speaking of pretty bad photos, a record shot of Tramea transmarina euryale, yet again. Although not common, certainly not rare either.

Male Pseudothemis jorina, another southern species. In Northern Vietnam common P. zonata occurs. I do not know where the border between the distributions of these closely allied species is, or whether there is overlap.

5-6 April - Cuc Phuong National Park

I travelled this weekend to Cuc Phuong with my birding pal and great friend Hein from the Netherlands. For birds. But we did see a few dragonflies along the way, some of it interesting because they are first observations for the season for me and indicate the length of the flight season.

Saturday was not very interesting, as it was mostly cloudy, but we did see Anax guttatus, 1 male and Cratilla liniata, Copera ciliata, C. marginipes, Pantala flavescens, Paracercion calamarum. Sunday brought the following: Epophthalmia elegans (2), Pantala flavescens, Diplacodes trivialis, Orthetrum sabina, O. pruinosum, Paracercion calamorum, Copera marginipes, C. ciliata, Brachythemis contaminata, Trithemis aurora, Crocothemis servilia, Hydrobasileus croceus (6), Tramea virginia (1), Ictinogomphus pertinax (2), Rhyothemis variagata (3), Neurobasis chinensis.

Quite pleased with Tramea and Hydrobasileus!

Tramea virginia, female

Another Tramea transmarina euryale

Saturday 7 September was supposed to become a clear day, so I headed to Ba Vi. And although I could for at least part of the day see that the plains in the distance were sunny, the mountain stayed in cloud and mist all day. Around 4.30 in the afternoon the resort cleared and while having a coffee I noticed a Tramea in the top of a tree. Although I could not verify it in hand, the wing pattern clearly indicates T. transmarina euryale. It is of course a female. This would be the second record for Vietnam, but given the fact that this is the second weekend in a row and at a completely different location, it likely has just been overlooked.

Tramea transmarina euryale, female

Tramea transmarina euryale

During a visit to Van Long Nature Reserve, Ninh Binh, last weekend, I stumbled into a Tramea with hardly any basal markings in the hindwing. Because Tramea virginia has very extensive markings it seemed likely that this was another species. In hand the primary and secondary genitalia proved that it was indeed another species, likely none other than T. transmarina euryale, possibly its first record for Vietnam. T. transmarina euryale is known for the limited extent of the basal markings in the hindwing, but in this specimen it is even more restricted than normal. That it is not just an aberrant T. virginia is shown by the close-ups of the hamule. 

T. transmarina euryale is widely distributed in south-east Asia, known for instance from Thailand, Cambodia and Hong Kong,  even ranging to Japan, and its occurrence in Vietnam was to be expected. 

Tramea transmarina euryale, male

Tramea virginia, male

Hamule and genital lobe, T. transmarina euryale

And for comparison, hamule and genital lobe, T. virginia