Differences between Nihonogomphus at Huu Lien and N. schorri at Xuan Son, a case for Nihonogomphus lieftincki

Yesterday, April 26, I visited Huu Lien. The day ended a little weird, when I was questioned by 5 guards demanding so see the insides of my car, the contents of a plastic bag (with Kameliya's rubber boots) and so on. It is of course good they keep an eye on things, so I tried to be cooperative to some extent. But the guy walking by with illegal electric fishing equipment was not even glanced at and the sound of chainsaws from various directions where people were cutting down any larger and accessible trees also did not seem to bother anyone, which made it look like a racial profiling exercise to me. But then again, ecotourism is quite an alien concept here and that anyone would want to take pictures of Odonata, well, weird…

Surprisingly, yesterday was rather sunny and I had another shot at various gomphids. I was able to catch two Nihonogomphus specimens and was struck by the differences with the Nihonogomphus schorri specimen from Xuan Son the other day. I doubt whether the differences are large enough to warrant a discussion of the species level, but it is an interesting case of geographical variation or inter population variability.

First, here is a Xuan Son specimen photographed perched and one from Huu Lien.

Xuan Son, Nihonogomphus schorri, male, April 13

Huu Lien, Nihonogomphus species, male, April 26

Apart from some differences in the coloration, the difference in shape is striking. I only saw one perched in Xuan Son, so it is difficult to generalize. But the difference is born out also by structural differences between the specimens caught. HW shorter and body longer in Huu Lien (BL 47mm against 44mm, HW 34mm against 35mm). (Measurements given by Do & Karube for N. schorri BL 45mm, HW 32.5mm)

The Huu Lien specimen in hand, different from the one perched in the photo

Xuan Son specimen in hand, also different from one perched in photo

An interesting difference, apart from the body shape also evident here, is the black line over the metapleural suture. The Huu Lien specimens all have a thin branch, sharply defined, which is much more diffuse in Xuan Son, giving the impression of a continuous broad black stripe rather than a branch. In the drawings by Do & Karube this branch is completely lacking and the stripe narrows dorsally.

What can already be seen here is the difference in shape of the first segment of the penile organ. Let's pull that close:

Huu Lien Specimen 1, look at the hook directed posteriorly

Huu Lien Specimen 2, identical hook

Xuan Son Specimen, no hook, just pointed straight down

What is interesting is that the shape of the first segment of the penile organ of the Xuan Son specimen is closest to the drawing in Do & Karube, which was of course based on Huu Lien specimens of N. schorri.

Huu Lien Specimen 1, appendages in ventral view. Note the inferior appendage is not spread and although bent upwards, reaches the shoulder of the superiors.

The Xuan Son specimen, spread in a V and falling short clearly off the shoulder  of the superiors

Second Huu Lien specimen, identical to the first specimen

Interestingly again is that the Xuan Son specimen fits well the drawings in Do & Karube, in which the inferior appendage is spread in a V and falls clearly short of the shoulder.

Dorsal view Huu Lien specimen 1

Dorsal view Huu Lien specimen 2

Dorsal view Xuan Son specimen

Note that the shapes and color are consistently different (in the small sample), also given the two in situ photos of life specimens. Both Xuan Son specimens (including the perched specimen) have half of S10 yellow, which is obscured in the Huu Lien specimens, but again clearly illustrated in Do & Karube.

The lamina of the anterior lamina is also drastically different. It is, in short, a completely different structure. And the anterior hamule, with a shoulder in the Xuan Son specimen, as to be expected for N. schorri, only broadens somewhat, without a clear shoulder, in the Huu Lien specimens.

This is a Huu Lien specimen, note the rectangular, but almost square,  lamina at the bottom of the structure

This is the Xuan Son N. schorri. Note the narrow and clearly excavated lamina, which also almost disappears under the adjacent structure. It is very different.

It is clear that the specimens from Huu Lien, the type locality of Nihonogomphus schorri, are a different species. As a matter of fact, shape of appendages and penile organ first segment, shape of anterior and posterior hamuli, measurements, black labrum, all fit very well Nihonogomphus lieftinck, a species from Fujian, Hunan, Hubei and also Guangdong in China. See the drawings in Chao (1954), and in Wilson & Xu (2009), including. The differences in coloration could be geographical variation. With a more thorough study of the type material of N. lieftincki structural differences might become apparent, but for the time being I call this Nihonogomphus cf. lieftincki.

A last few photos from Huu Lien* **

*Updated after publication of Paracercion ambiguum
** Updated again after publication of Lyriothemis kameliyae

Here are a last few photos from Huu Lien. It is Wednesday evening, so ready to start thinking of the coming weekend. But for now it is misty, rainy and cloudy, as it has been the last two months. Nevertheless, a few more shots of species seen on April 21. Tetracanthagyna waterhousei is new for the blog.

This is a male Prodasineura autumnalis, a rather common species

And this is a beautiful male Lyriothemis kameliyae. 

This is the Paracercion ambiguum male, a new species to science. 

And finally a female Tetracantagyna waterhousei. This bulky mama flew up higher into the trees, so I could not get better shots. It is a monster of a dragonfly.

Some additional species at Huu Lien from April 21

The two Copera species of Huu Lien and the one Pseudocopera were already common and easily found. Here are the males of P. ciliata and C. marginipes in their full glory.

Pseudocopera ciliata is the easy one, large, and white when mature

Here a male Copera marginipes with its simple, but large superior appendages

A somewhat messier C. marginipes. C. vittata normally has much less white on the last segments.

A remarkable and large species was Orolestes selysi. The dark-winged form and the hyaline form occurred side by side.

A fantastic dark-winged specimen of Orolestes selysi

The somewhat less striking, sorry to say, hyaline version.

I also had the opportunity to take a better look at some immature Orthetrum glaucum.

First, a female Orthetrum glaucum.

A fresh, still less pronounced, female

The interesting immature male. The striking pattern is later completely obscured by pruinosity.

Idionyx carinata at Huu Lien

April 21 I was checking for dragonflies inside the forest in Huu Lien Nature Reserve in the afternoon under a cloudy sky. My attention was drawn by a dragonfly cruising up and down a slight opening over the trail. Caught, it appeared to be a female Cordulid. Checking at home it became quickly apparent this is an Idionyx species. Karube (2011) described 3 species for Vietnam, Idionyx victor, I. carinata and I. asahinai. The latter two have the same thoracic markings are my female and the double horn on the vertex points to I. carinata. A further difference with I. asahinai is the facial pattern, with a small yellow spot on the center of the anteclypeus, whereas in I. asahinai the whole labrum is also yellow.  

I. carinata is widely distributed in Southern China and apparently also in Northern Vietnam, as Karube mentions specimens from Tam Dao, from Cuc Phuong and also from Cao Bang Province. By the way province is the province west of Lang Son, in which Huu Lien is located. 

Fraser (1924) mentions I. optata as very similar to I. carinata, but states for instance that the anal loop of carinata has less cells (4-6 cells in carinata and 12 in optata). However, this was based on only one female and one male specimen. The photo of I. carinata in Karube show around 12 cells in the loop. My specimen also has 12 cells. Of course I will be happy to see a male next time!

Idionyx carinata, female, scan of dorsal side

Same female in ventral view. Note the straight yellow stripe and the extensively yellow metepimeron, yellow extending onto metepisternum.

Note the double horn on the vertex and the small yellow spot on the anteclypeus (and extending marginally onto the labrum)

Huu Lien Gomphid enigma*

*Adjusted after publication of the Tombo May 2015 issue, in which Haruki Karube published Trigomphus kompieri.

Yesterday, April 21, I visited Huu Lien Nature Reserve and ran into 4 Gomphid species. Nihonogomphus schorri, after all it is the type location, and Ictinogomphus pertinax will not raise eyebrows. A small gomphid of which I saw 4 individuals should. It appears to be a Trigomphus species, a genus not recorded from Vietnam, although it has been recorded with several species from southern China. It has appendages close to those of T. succumbens, but the thorax markings and facial markings are rather different. Especially the thick black line along the metapleural suture, the so-called third lateral stripe, is strange. If correct, this species awaits description. Please see the below photos and if you know what it is, tell me. (It was subsequently established that this is a new species of Trigomphus, described as T. kompieri (Karube, 2015)

Besides, I also saw another, large, Asiagomphus. I was able to take some photos, but these do not show the abdomen tip. I doubt anyone will have the audacity to identify it on basis of the photo, but I add it at the bottom nonetheless.

The very, for a Trigomphus, blackish male of T. kompieri.

At about 45 mm not a large insect, for a Gomphid

Appendages in ventral view

More striking, because of the white color of the superior appendages, in dorsal view

Close-up in lateral view, of course upside down. This is the right side. The superior appendages have a large ventral tooth at 2/5th and a serrated distal edge, inferiors smoothly curved.

The left side, lateral view, this one uppers up and lowers down.

The right superior appendages in dorsal close-up. Ventral tooth also visible as lateral tooth, but it is one and the same.

The other, large, enigmatic Asiagomphus. Note the narrow lateral yellow stripe.

Lestes nodalis - a weird Lestes!

April 21 was Easter Monday and thus a holiday for me. After two days in cloudy Hanoi I just had to go somewhere, but the weather was not appealing at all. I decided to go for it anyway and drove to Huu Lien Nature Reserve. Huu Lien is a brilliant place for dragonflies, still, but there is always the sound of chainsaws in the background and I dread seeing cut down trees left and right in the last decent patches of the forest. Also, the water quality is deteriorating. All in all I hope that we will be able to enjoy the bounty of the place also in years to come. Anyway, I had nearly 50 species on a mostly cloudy day in April, not bad at all. I saw two Gomphids I had not seen before, one of which I could catch. More on that later.

When checking a field laid bare with some weeds near a shallow stream that dries out in winter, bordering agricultural lands, I noticed a weirdly colored Lestes. I was able to take some pictures and catch it, but afterwards I saw nearly 10 more, both males and females. Checking the literature at home it turned out to be Lestes nodalis (Selys, 1891). A species known from Thailand, Myanmar, India, and bordering China (Guangxi, Yunnan), so it is maybe not surprising it also occurs here in Vietnam, but it had not been recorded before, so another addition to the Vietnamese list!

The coloration of both the male and the female is rather peculiar, lacking the metallic shine so often seen in the genus. The appendages are very typical and the pterostigma is dark with a light border all around.

Lestes nodalis, male

Another male, showing off its fabulous colors

Close-up of head and thorax

The female is not less weird in color, maybe more so

Another female, note also the darker trailing edge of the slightly amber wings

Appendages of the male in dorsal view. Superior appendages with distally pointed projection, mostly pale yellowish with black tips.

Megalestes micans - emerging left and right at Sapa

When birding around Sapa we encountered everyday large spreadwing damsels. Only once did I see a mature female, which eluded capture. And only once was I able to put my hands on a teneral male, as females were much more common. The large square ventral tooth at the base of the superior appendages, which were otherwise smoothly rounded without widening in the distal half, pointed straight to Megalestes micans. The HW length of 35mm also nicely fitted the species. In these teneral individuals the thorax has a broad yellow stripe along the dorsal carina that apparently disappears completely in the mature specimens. It is therefore not clear to what extent the yellow pattern on the prothorax remains as it is in the below photos. M. micans has a typical pattern to the prothorax with yellow anterior and posterior lobes, connected by a yellow line over the prothorax itself, which fits nicely with the present markings, but it is likely that at least to some extent these markings will be obscured later. The shape of the appendages however leaves no doubt about the male and likely the accompanying females are thus of the same species, even if M. haui has also been recorded in the area (Do Manh Cuong in litt.).

Megalestes micans, female, teneral, with yellow middorsal stripe and yellow prothorax

The same female, carefully captured

The teneral male, stupidly forgot to take picture of the whole insect, note yellow mid dorsal stripe and posterior lobe of prothorax

The superior appendages, smoothly rounded and if you look carefully, with square ventral tooth visible near the base.

Another teneral female