Thursday, 28 April 2016

Hemicordulia tenera - an emerald at Da Lat

April 17 I caught a medium-sized emerald along the edge of Tuyen Lam Lake, at one of the swampy corners of the lake where a small stream runs into it and creates boggy conditions. It was ovipositing in a pool surrounded by grasses. It is always a happy occasion to bump into emeralds, no matter where you are in the world. They tend to be scarce. In Vietnam I have only seen Procordulia asahinai, but that was at Sa Pa. Da Lat is a different world, of course. It is of course possible that there are undescribed emeralds in Vietnam and I did my best the day after to find the male, but I could not. As far as patterning and the vulvar laminae are concerned there is no reason why this would not be the female of Hemicordulia tenera, a species that occurs for instance in nearby Thailand. Here are a few pictures.

Female Hemicordulia tenera. She has long legs, that is for sure.

Scan of the same female, showing the venation.

Coeliccia species from the south*

*Adjusted on January 20, 2017. Paper was published on C. mattii so I added its name here.

Just a few weeks ago Rory Dow published Coeliccia suoitia from the Da Lat area. I revisited the location where I had observed them in December last year and this time (April 16) found the undescribed female and a single male. Finding the female proved that the female I had included in my December post was not the female of C. suoitia at all. I deleted the photo from the post, in case you did not notice. The real female has similar colours and pattern to the male and has two lateral horns to the prothorax. This is very interesting and supports Rory's assumption that this species is not a regular Coeliccia at all.

Female Coeliccia suoitia

At the same location and same date I also caught a single male and observed another of a different species and it is likely that the female I photographed in December concerned this species. It is mostly yellow-and-black, and it has been suggested it is a form of Coeliccia montana. I doubt that very much. It is larger and has a different thorax pattern. It shares pruinosity on the prothorax, but in addition also has a pruinose spot on the mesepimeron. And it has paler and differently shaped appendages, with less yellow on S9-10. I was informed by Wen-Chi Yeh that he has a similar specimen from the general Da Lat area, which shares all these peculiarities. For the moment this remains a Coeliccia sp. novum, to be described when we can bring the various materials from this area together in a paper.

Coeliccia sp. novum, note pale appendages and lack of yellowish on S9

C. montana-like pruinose prothorax, but note pruinose spot on mesepimeron and yellow, not whitish coxae.

At a different location at the bottom of a very wet small valley in undisturbed forest a smallish Coeliccia caught my eye on April 18. It seemed to have a pale blue thorax, like Coeliccia poungyi, but upon close inspection it turned out that it had a largely pruinose thorax, so it did not have real blue, but the underlying colour was black. Non-pruinose parts were yellow. It was considerably smaller than the aforementioned species and clearly undescribed. But it turns out that Wen-Chi Yeh also collected it around Da Lat and specimens from Rory and Matti Hamalainen are stored at Naturalis, Leiden. This species was described in 2016 by Toan and me as C. mattii. The female is a lot like the female of the aforementioned species and also like that of Coeliccia montana, but smaller.

The other Coeliccia mattii male with pruinose thorax and prothorax and yellowish appendages

Two males and a female of Coeliccia mattii (top three) and Coeliccia sp. novum 1 (bottom), showing big difference in size.

The last Coeliccia I found new on my recent trip to Phu Quoc (on April 12) was Coeliccia yamasakii, a specialty of Phu Quoc (as far as Vietnam is concerned). I found only a single male and 3 females at a single location. Although it should be more easy to find, it was in fact very hard to find and I guess that has to do with the extreme drought. But I was a happy chappy.

Coeliccia yamasakii male, recognizable by the small greenish yellow thorax spots and all dark abdomen with only the appendages paler. This is an adult, the subadults males have more extensive pale areas on the thorax and abdominal tip. 
The female of Coeliccia yamasakii, relatively blueish.

Tuesday, 26 April 2016

Heliaeschna crassa new from Phu Quoc

On April 14 I was trying my luck towards dusk at a small pool inside swamp forest on Phu Quoc. This was the pool where I had found Rhyothemis aterrima during the daytime and although nearby a dead dog had been dumped in a bag, it was not nearly smelly enough to keep me from staking out for Aeshnids. And as luck might have it, a large Aeshnid did in fact show up and even luckier, when I struck out for it I caught it. It was large and did not look familiar. The appendages looked a bit like what I remembered from Asahina and indeed: when I checked later it turned out to be Heliaeschna crassa. Having said that, this species may be a junior synonym of Heliaeschna idae. However, since convention calls the specimens in countries just west of Vietnam H. crassa, I will stick with that.

This species has long superior appendages that bend inwards towards the apex and are slightly expanded, but the epiproct is short and hooked upwards towards the posterior end. The face is ochre, with an indistinct dark spot on the postfrons that does not form a real T-spot. The eyes are also largely ochre in colour. The thorax is green with reddish lines over the sutures. The wings are pale brownish enfumed, but with dark brown along the subcosta becoming less distinct after the first 6-7 cells or so. Asahina actually describes the thorax as mainly dark reddish brown and the face as reddish brown. Maybe he worked with faded specimens?

The beautiful monster: Heliaeschna crassa. Note the largely ochre eyes.

And the ochre face, for that matter

Positrons with dark vague diamond

Appendages in lateral view, with hooked epiproct.

In dorsal view. Sadly the right appendage was damaged

Two little forest friends from Phu Quoc

There are two species of smallish dragonflies that occur in the forests of Phu Quoc towards the end of the dry season. And I really wanted to see both of them, because they are stunning. Neither of these two are rare, but they reach the eastern limit of their distribution in the very south of Vietnam. I was happy to see quite a few. Brachygonia oculata is the commoner of the two, but I also saw plenty of Orchithemis pulcherrima. The latter is small, the former is in fact tiny.

The male of Orchithemis pulcherrima stands out in the darkness of the forest with is bright red abdomen 

This is the same specimen in dorsal view

The immature female is not nearly as bright

And neither is the female. Her thorax pattern is somewhat reminiscent of the smaller Brachygonia, but apart from the general shape of the abdomen and her size another obvious difference is the pattern on S8-10, with black restricted to the area adjacent to the dorsal carina
This little stunner is Brachygonia oculata. The different colour bands on the abdomen are really something.

Another male in all its splendor

And the female, showing all blackish S8-10.

Monday, 25 April 2016

Two new Rhyothemis species from Phu Quoc

On April 12 to 15 we visited Phu Quoc Island to see a few of the dry season specialties. This year is exceptionally dry and the island suffers from break-neck speed development and ground water abuse, but I was able to locate many of the goodies that I hoped for, although not all. Amongst these were two Rhyothemis species that I had not recorded before. One of these is known to occur in the island and although numbers are low, I bumped into it at a handful of widely separated locations. This is the smallish and wonderful Rhyothemis obsolescens.

The other I did not recognize. At a pond in the forest on several days I observed a male Rhyothemis perched that looked a lot like R. plutonia, but the greenish iridescence on the wings seemed more extensive and the remarkable purple of that species was missing. The wings seemed to have a reddish ground colour and towards the tip the greenish colour was visible as dots too. I tried to catch it, but I could not. In the end it dawned on me that this is Rhyothemis aterrima. This species has been recorded in Vietnam before. Cuong & Hoa list a record by Asahina from Binh Duong Province from 1962. But I know of no other records. Supposedly it is not uncommon in for instance Malaysia, but it is difficult to find photos on the web, so maybe it is actually not that common. I am very happy with it.
This is the wonderful male of Rhyothemis obsolescens. The pale borders to the wings give them a sort of out of focus aspect.
From below the golden shine is missing, but the brown and paler areas form a beautiful pattern. It excels at holding its wings at different angles.
Although this specimen takes a more conservative pose.

This is the difficult Rhyothemis aterrima male. This photo is a little too dark and therefore it looks quite a bit like R. plutonia. But note the relative slender hinds wings, extensive green and lack of purple.

Much more apparent in this photo is the reddish ground colour of the wings and it can be clearly seen that the green on the outer wings forms distinct dots.

Sunday, 24 April 2016

Sinolestes editus - A cool addition to the Vietnamese list*

*Sebastien found a photo of this species on the internet taken at Tam Dao in 1999, so it is not really the first record

On Sunday April 24 I went to Tam Dao 2 and walked part of the long trail. It is still early in the season and the morning was misty, so I did not see many species, although I was happy with many Bayadera continentalis, a species I only know from Pia Oac.

But I bumped into what I considered a Megalestes species, hanging inside a small bush. But it had a pale yellow humeral stripe and seemed a little odd. When I caught it I also noticed the rounded appendages, without the thickened apex of the Megalestes species that occur here. I did not notice the slight grayish area distal to the pterostigma or my suspicions would have been roused further. However, when I found another individual a little later, this specimen had distinct half-bands distal of the pterostigmata, something never seen in Megalestes.

At home I could solve the mystery and was happy that I had a new genus for Vietnam: Sinolestes. Originally Needham (1930) described three different species for the genus, but since they have all been synonymized. Now only one species is recognized, variable Sinolestes editus, which sometimes has almost all of the outer wing, apart from the apices, completely dark, but more often a band across the wing behind the pterostigmata, or sometimes even hyaline wings. S. editus occurs in southern China, including Guangdong, Guangxi and Hainan. Maybe it is not surprising it also occurs in Vietnam, but it is a large and conspicuous species, so it likely is not common.

Sinolestes editus, male. Note the dark bands in the wings. And the appendages that slant upwards.
The female also has a distinctive feature. Note the lateral yellow squares on S9.
The appendages of the male in dorsal view, nicely rounded

Saturday, 23 April 2016

Sarasaeschna minuta - superb addition to the Vietnamese list

 I was very excited when I bumped into a hovering Sarasaeschna species on April 17 at a stream near Tuyen Lam Lake near Da Lat in South Vietnam. I missed when I tried to catch it, but later caught another specimen and still later a second. Indeed, a small Sarasaeschna species. My fifth species of the genus for Vietnam.

Checking against Asahina's description of Sarasaeschna minuta it matched very well. He described Sarasaeschna minuta in 1986 from a specimen collected in north-east Thailand. As far as I know this is the only record and it is thus also known from only one location. This is therefore a very exciting discovery. The original record was from 1000asl, the current locality about 1350asl.

In fact there are two discrepancies. The first it that the superior appendages have a ventral tooth at the start of the broader section, which is not evident from Asahina's drawings. But otherwise the shape of the appendages is just too good. Also, Asahina described the abdomen as 30mm and HW 28mm. My specimen has HW 28mm, but the abdomen is 36mm. It would need verification against his type specimen, but I think the description may be faulty on this point.

Male Sarasaeschna minuta in hand
Scan of the same male

Appendages in ventral view. Note the long epiproct, which is incised apically in a horse shoe shape

Here in dorsal view you can see that the broader section of the superiors starts with a tooth

Thursday, 21 April 2016

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.

Tuesday, 19 April 2016

Anax indicus - new for Vietnam with thanks to Sebastien

Yesterday Sebastien Delonglee sent me a photo of an Anax he photographed smack in Hanoi at a pond. Immediately obvious from the colour and configuration of the spotting on the abdomen was that this was Anax indicus. And because this species had not previously been recorded in Vietnam this was quite exciting indeed! Apparently there is a record from Hong Kong, and of course Anax species are notoriously strong flyers with great dispersal ability, but even so.

Today Sebastien went back to the same pond in order to get better photos. I myself had to go on a business trip and needed to postpone looking for it myself, sadly. But on my way to the airport I had to pass by my house to pick up my suitcase. With a few minutes to spare I took a peak at the swamp behind our appartment building and jokingly said to Kameliya that I would find one there. To my immense surprise a slow flying Anax was patrolling the small area of open water close to the temple on the other side. Obvious was immediately the largely yellow abdomen: Anax indicus! Although I scurried downstairs with my camere and rode my bike (with a flat tyre) to the otherside, I could there only see it take off. Then I had to dash for the airport. So, no better pictures than those of Sebastien (that would have been difficult anyway), but a very cool record. This sort of suggests there may be an invasion going on, possibly triggered by the drought in the Mekong basin.

Here is the very cool photo by Sebastien of the specimen seen yesterday.

Absolutely brilliant photo by Sebastien of Anax indicus

Monday, 11 April 2016

Another Rhinocypha, sadly forgotten

On 25-27 September I visited Quang Nam Province around P'rao on the HCM Highway and on the 26th spotted a Rhinocypha up in a tree above the stream. I could make some quick and dirty photos just before it flew off, never to be seen again. It is superficially similar to R. seducta from the previous post, but lacks the dorsal stripes. It is R. watsoni, a species from Central Vietnam. I forgot to post it, but now that James produced R. seducta, I remembered this species from last autumn.

Male Rhinocypha watsoni up in a tree in broad sunlight

Two new Rhinocypha species from Cat Tien National Park

Today I received a message from James Holden. He had done some deep exploring into the forests of Cat Tien National Park and although it had been excruciating, he also came up with some goodies! Two photos of Rhinocypha species he sent could readily be identified as two species that I wished I had seen. Both are apparently rare. R. fulgipennis is easily confused with immature R. fenestrella, but the colour of the wing is different. R. seducta shares dark-tipped wings with R. watsoni, but has broad orange red dorsal stripes on the thorax. I tip my hat to James for finding these cool species!

Male Rhinocypha fulgipennis, courtesy of James Holden

Brilliant Rhinocypha seducta, courtesy of James Holden

Thursday, 7 April 2016

Four new Protosticta species described for Vietnam

Today Zootaxa published our article on Protosticta in Vietnam (Quoc Toan Phan & Tom Kompier: A study of the genus Protosticta Selys, 1855, with descriptions of four new species from Vietnam (Odonata: Platystictidae)). Two species I already published on my blog. Today I could officially add their names: P. socculus and P. spinosa. Please see under Protosticta.