Tetrathemis irregularis hyalina - the second Tetrathemis

During our second survey of Cat Tien National Park in November we encountered a great many of the lovely little Tetrathemis irregularis hyalina. This species had already been reported from Cat Tien and it was one of very few species reported and not yet found in the first survey and by James Holden. In August I did see just a couple of Tetrathemis platyptera, or so I thought. That made me somewhat skeptical concerning the occurrence of T. irregularis hyalina, but both species do occur in the same habitat. So, it should not have come as a surprise when we saw them all over the place this time round. Clearly it is absent during the wet season. We saw them along moderate slow and muddy streams and at pond and puddles in the forest. There was also one at the fishponds, so it tolerates a high variety of habitat. Although I was pretty sure I saw amber in the wings of the few females I saw in August, conditions were terrible, in the rain. Checking the photos, it seems that the size of the abdominal markings is in favor of T. irregularis hyalina, as is the color of the eyes. I apologize and correct myself...

Although very similar to T. platyptera, T. irregularis hyalina has completely clear wing bases (with large amber basal spots in T. platyptera)

Another male, perched by a pond

The neat facial pattern with pale-yellow anteclypeus and postclypeus and sides of antefrons.

The female of T. irregularis hyalina, with only limited markings on the abdomen compared to female T. platyptera.

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.

Tetrathemis platyptera and Rhinagrion hainanense

On June 8 I was oding in Xuan Son. On the verge of the reserve I first visited the large stream and in some ponds bordering it I found a small dragonfly I had been looking for for quite some time. Last year in Ba Be I saw it from the corner of my eye, but although Sebastien saw them several times at Xuan Son (see his blog), I missed out. But there it was. And although I could only get some shots from a distance, I was happy.

Later, inside the reserve, I twice bumped into beautiful Rhinagrion hainanense. First a fresh female, just emerged from the stream along the dam and later a male along one of the minor streams flanking the large stream with the bridges. I featured it before in the blog, but this is a species you can never see enough of.

Cute, small, Tetrathemis platyptera, male. Yes, I know, calling a dragonfly cute is degrading to the insect, but hey, it is pretty.

Freshly emerged Rhinagrion hainanense, female

And yet another handsome fella. Rhinagrion hainanense, male