Sunday, 23 April 2017

Not a Bao Loc specialty - Heliogomphus chaoi

Karate (2004) described Heliogomphus chaoi from Bao Loc in Lam Dong Province in the south of Vietnam. This species is very similar in appearance to Heliogomphus selysi, a species occurring in for instance Thailand. H. chaoi differs especially in the shape of the vulvar scales of the female and the lack of prominent spines on the occipital ridge. In stead it has two small horns behind the lateral ocelli. Karube also notes that the superior appendages have a ventrolateral projection at the midpoint, to separate the male from H. selysi. Indeed, Asahina did not mention this for H. selysi, but I would love to see the holotype to verify this.

Anyway, last year I found this species to be common near Bao Loc at the type locality in early June. But a few days later I bumped into another small Heliogomphus in Gia Lai Province. Outward it was a little different in coloration. Notably, the superior appendages were more extensively white and S7 had a distinct anterior pale yellow ring. With differences between Heliogomphus species often slight, I thought it might be a different species, but checking it under the microscope I cannot but conclude the appendages and vesica spermalis are identical. If so, the slightly different coloration is likely nothing but a geographical variation. I concluded that the Gia Lai specimen is also H. chaoi. That species is therefore much more widespread than previously thought.

Heliogomphus chaoi in Bao Loc. Note it only has on S7 a pale yellow line along the dorsal carina and a lateral basal spot.
Another male at the same location
And the appendages in dorsal view
Heliogomphus chaoi at Gia Lai. Note the small yellow dorsal spot on S8 and the large anterior yellow ring on S7. But structurally it is not different.
The appendages in dorsal view, the white more extensive

Sunday, 16 April 2017

Macrogomphus kerri - wonderful addition to the Vietnamese list*

*adjusted: it also occurs in Cambodia (thank you Oleg).

According to the IUCN website, Macrogomphus kerri may be an endemic to Thailand, where it is widespread, but uncommon. Well, sorry for the Thai, but it is not an endemic after all. 18 June 2016 I visited Gia Lai Province in the Central Highlands of Vietnam. A wonderful small, muddy stream in logged primary forest was a real treasure trove, with 6 species of Macromia flying at the same location, and many other goodies. This large and strikingly beautiful Macrogomphus species, easily recognizable by its bold patterning, was one of those. Not at all rare, I saw quite a few, including ovipositing females. Males tended to sit on or under bushes over the stream. Here are a few photos.

Beautiful male Macrogomphus kerri, perched
Another male, hovering over the stream in a dark place, hence the flash
Male in hand
And the rather similar female

Saturday, 15 April 2017

Amphicnemis gracilis - little critters on Phu Quoc

Last year August I went to Phu Quoc Island to find a few species I had not yet seen there, but that had been recorded from the island. One of these was Amphicnemis gracilis. It turns out it is really localized and frequents swampy forest with lots of ferns. It was not at all easy going, but once I knew how to find them, I saw plenty. They are inconspicuous, sometimes hanging from tips of leaves, but also sitting on twigs and other stuff on the muddy ground. The immature females are pretty, with their red thorax. When maturing they become bluish green. The males are shiny metallic green, with intricate white and very vulnerable appendages. All males had a recurved spike on the prothorax that had not been described for this species, but the caudal appendages are in line with what you would expect of A. gracilis. The genus is, according to Rory Dow, extremely difficult, so I decided to just accept the spike as a local peculiarity. This is the only place in Vietnam where it is known to occur.

A male Amphicnemis gracilis. They hang out in the dark, so it is all flash work.

Another male
And yet another
These fleshy things are the caudal appendages
And here you can see the recurved spike from the posterior lobe of the prothorax
The really pretty immature female

And this is what she looks like all grown-up and ready for action. You might think it is a different species, but no.

Monday, 10 April 2017

Orthetrum internum headaches

Last Thursday I was in Sa Pa and as usual this time of the year Orthetrum internum was already out in good numbers. Wen-Chi Yeh had responded to my posting of the species in 2014, but I had overlooked the significance of his comment. Basically he said that my photos looked different from what he was used to for O. internum. I had noticed that lack of pruinosity on the  dorsal side of the thorax, but in my posting mentioned this as one of the characteristics of O. internum. How wrong can you be?

Yesterday I visited Pia Oac in Cao Bang and ran into O. internum is several places. This in itself is strange, because I had never seen it there before. But even more strange was the fact that they were clearly pruinose and much more black-and-yellow. These were true O. internum! But if so, then what is the species in Sa Pa?

Structurally the two are identical. I am not sure if there are structural differences visible to us between O. internum and O. japonicum. These two were considered subspecies of O. japonicum in the past, until DNA sequencing made it clear they were in fact separate species. So, the lack of structural differences does not necessarily mean that the Sa Pa species is O. internum, nor does it support the other option, of course. But in coloration it is very different. The labium and labrum are pale orange, not black. The frons lacks black edges dorsally. The venter is not nearly as black, with the hamulus pale brown with only the tooth darker brown, but it is black-and-white in O. internum. And the thorax ground colour is black or dark brown in O. internum, with clear yellow on the prothorax (especially posterior lobe). In the Sa Pa species the ground colour if brown with pale markings, and there is no yellow on the prothorax, just pale areas. And most interestingly, there never is any pruinosity on the dorsum of the thorax!

From Sa Pa, note orange labium and labrum, brown color of thorax, no pruinosity, pale thoracic markings. Photo taken in 2014
Last Thursday. Note some characteristics. 
But this is a very black O. internum. Note also black labium and labrum, black on top of frons, pruinosity on the thorax, from Pia Oac
In dorsal view
A slightly less black male from Pia Oac. Note also the clarity and extent of the yellow markings on the thorax.
Note the yellow posterior lobe of the prothorax.

Friday, 7 April 2017

Lyriothemis kameliyae published in Zootaxa

Yesterday Lyriothemis kameliyae was published in Zootaxa. This is not at all a difficult species to recognize once you realize that it is actually different from L. bivittata. Problem is that all Lyriothemis species flying around in southeast Asia with a double yellow lateral marking on the otherwise brown thorax and with a red abdomen, plus dark streaks at the wing bases, had been lumped together under L. bivittata. In fact, there are at least several species involved. L. kameliyae occurs together with L. bivittata in northern Vietnam. Xin Yu already wrote to me he had collected L. kameliyae in China. Undoubtedly it is quite widespread. As beautiful as it is, it remained anonymous, until now!
Male L. bivittata (top) and male L. kameliyae (bottom). Spot the differences!

Sunday, 2 April 2017

April 2 - Huu Lien and first gomphids

April 2 was a nice spring day to look for the first gomphids of the season in Huu Lien Nature Reserve. As always, the first impression was of clearance progressing, but like last year end of March, Trigomphus kompieri was about at various locations. The first I bumped into was a female, but like last year, I could not catch it and did not get a picture! Trigomphus is genus of early gomphids. Paragomphus may actually be year round, although rare in the winter, I think they may be around. Anyway, there was a male about too, interacting with the Trigomphus. I also saw quite a few Paracercion melanotum and fully mature Gynacantha subinterrupta. Below a few photos.

The first male Trigomphus kompieri of the day, a little difficult to get a clear shot.
And the third. Somewhat easier. The second eluded the camera.

Paragomphus capricornis against a muddy stream background.

Paracercion melanotum male

And Gynacantha subinterrupta showing well