Friday, 29 May 2015

New Year's Resolution 2 - the smallest of the small

May 9 and 10 I visited Hong Linh (the hometown of Toan) in Ha Tinh Province. This is the south of northern Vietnam. Objective was to see Nannophya pygmaea, the smallest of dragonflies. Close to Hong Linh is a pine forest with an open stream and it occurs here along that steam in smaller puddles on and between the rocks. Here another very small, if not as tiny, dragonfly occurs, although apparently in small numbers compared to the commoner Nannophya pygmaea, of which I saw a few dozen. I saw only two Nannophyopsis clara, one adult male and one freshly emerged. A strange little metallic thing that curls its abdomen constantly under its body. Both species are decidedly fly-like when they move about. The specimens I observed of N. clara were at slightly larger pools than N. pygmaea seemed to prefer.

N. clara is a species of southern China, including Taiwan, and Vietnam. N. pygmaea occurs over a much wider area. It is apparently common further south in Vietnam, but I never saw it in the north. That is, until now.

Nannophyopsis clara, a tiny metallic species that constantly curls its abdomen. This is a male.

Nannophya pygmaea, a male. It is actually redder than this, but my Canon fails to capture that colour well.

An immature male, lacking red

Another immature male

The pretty female of N. pygmaea, quite vividly marked

Wednesday, 6 May 2015

Hylaeothemis clementia - again

On April 30 on my way to Pia Oac Mountain close to the weak bridge along the TL212 about 10 km south of the mountain I checked a small stream by the roadside. It has a small several square meter muddy wet area adjacent to it, due to some seeping water, with low plants. I was amazed to see three males of the very same species I had seen in Yen Bai only a few days earlier for the first time: Hylaeothemis clementia. This was clearly its habitat of preference, with the three males all holding territories in close proximity (about 1.5m apart). Here are a few shots to show what they look like when mature.
The eyes now blue and the dorsal stripe on the thorax now white. 
Another view, square on laterally, but not entirely in focus, sorry

Tuesday, 5 May 2015

New Year's Resolution 1 in the pocket

I visited Mau Son several times before, but had failed to find the beautiful Rhinocypha chaoi that occurs there. I now had a vague inkling of where the stream was supposed to be that they inhabit and I plunged down the hills into the valley beyond Khuoi Cap Village, fighting my way heroically through the forest and the bamboo stands. And reached the stream. But not a single Rhinocypha chaoi in sight. A nice big stream with larger boulders, quite different from the trickles elsewhere on the mountain, but no jewels. I found a trail from the stream back towards the village, which was a great help, it being 36 degrees and a steep climb anyway. And the next morning, May 3, I made it back to the stream again. Lo and behold, there it was, a fresh male Rhinocypha chaoi. Not yet the fantastic blue creature in the New Year's Resolutions entry courtesy of Toan, but I was thrilled and happy to see it nonetheless. Clearly it is still early in the season for it. It should be more common towards the end of May.

Rhinocypha chaoi was described by Wilson in 2004 and is apparently widely distributed in southern China, although in Vietnam it is only known from this one site. Here are a few shots of it.

It will be much bluer, especially on the abdomen, but the basic pattern is already visible: immature male Rhinocypha chaoi.

In this photo of the same individual the areas on the abdomen that will be blue are already obvious.

Monday, 4 May 2015

Bayadera continentalis - new for Vietnam

Asahina described Bayadera brevicauda continentalis in 1973. On clear consistent differences, both morphological and in colour pattern, Hamalainen in 2004 elevated it to specific status as Bayadera continentalis. It is a species known to occur widely in southern China and thus, as so often, it comes as no surprise that on May 1 I labored my way along a trickle of a stream under dense forest cover on Pia Oac Mountain, quite close to the top at the northern side, that I ran into at least 5 males of this pretty species. It is quite distinctive by virtue of the shape of its appendages, its dark coloration with pruinosity on S8-10 and S1-3, and its smoky brown wings. Other characteristics include the all black labium and the distinct hairy thorax. To my knowledge this is the first record of the species in Vietnam, but it may have been recorded before. If so, I stand corrected.

Bayadera continentalis, here under flash the brown of the wings is difficult to ascertain
Here too the colour of the wings is difficult to see
But on this scan it is obvious
Parallel inferior appendages and apically strongly bent uppers in dorsal view
And in lateral view
And just because it is a nice face, the frontal view of the head

Sunday, 3 May 2015

Atratothemis reelsi - new for Vietnam

2-3 May I travelled to Mau Son with Haruki Karube and small party of Japanese students. In the afternoon I walked to the end of the trail that does not bent down to the village on the slope and by-passed a pool on the left side that looked in pretty bad shape, muddy and green in places. Although fed by a seep and probably originally a nice natural pool, it now is visited frequently by a group of water buffaloes. That does the water quality no good. But there were several species flying about, so I looked and my attention was drawn by a fluttering dragonfly with large blackish wing patches. In a way it reminded me of flying Dysphaea basitincta, but of course that was not it. When it perched it seemed to be a Rhyothemis, but not a species I knew. Later checking the literature I thought it might be Rhyothemis severini, although it is not blueish, but all brownish black in the wing. The apical spots in the wings were more distinct as well. Haruki collected a male for DNA research, to check whether it is in fact maybe distinct from typical R. severini. This was the status quo and I first published this here on the blog as the rediscovery of R. severini, 116 years after it had been described by Ris on the basis of a single specimen, collected in 1899, from "Indochina".  We considered this a very exciting turn of events. However, the starting assumption that this was a Rhyothemis was wrong. Luckily a reader of my blog pointed towards the solution, a solution that explains the differences in patterning with R. severini. It is a different species called Atratothemis reelsi, a little known libellulid described by Wilson in 2005 and known from Guangxi, Guizhou and Hainan in China and likely also occurring in Lao DPR. This is supported by the characteristics of its wing venation and secondary appendages. The occurrence of 2 males at a muddy hole at 1000m altitude was a huge surprise if it had been R. severini, but may fit Atratothemis reelsi better, although next to nothing is known about its habits.

Atratothemis reelsi, with typical large apical spots and large blackish basal marking in hindwing bordered along trailing edge by whitish cells. 

No blue shine whatsoever, as would be expected in Rhyothemis severini.

Specimen in lateral view

The fantastic blackish brown insect in dorsal view. Note the undulation of R3, the many cross veins in the bridge and the three-celled triangles in FW and HW. It does have even more cross veins in the cubito-anal spaces than described for the genus by Wilson (2005)