Showing posts with label Davidius. Show all posts
Showing posts with label Davidius. Show all posts

Thursday, 24 July 2014

Loose ends

So, wah loose ends remain from the mid-summer road trip around northern Vietnam? In Pia Oac in early July I ran into a whole bunch of small gomphids one afternoon. The turned out to be Davidius. But which species? There has been some confusion about Davidius fruhstorferi, with various subspecies described and some split as separate species, or lumped again. Clearly, this species belongs in the fruhstorferi corner, but the thorax pattern is a little different, it is a little smaller and the appendages, although similar, are not excavated laterally and smaller than in the specimens I saw in early spring at Yen Bai. Now, it is possible that indeed this is subspecific variation, but I am not so sure. It would not surprise me if in fact this turns out to be a different Davidius. Nevertheless, for the time being it look as if it will go down in history as Davidius cf. fruhstorferi.

A tiny gomphid, and please note the nice black square mark laterally. But let's pretend it is Davidius fruhstorferi, a male
Then this is the female. And clearly the square mark is not a fluke. All individuals, including this female, displayed that characteristic, which I have not been able to find in any description of any subspecies.

In copula, working to produce many little gomphids

A female in dorsal view. Along a tiny stream in the forest it was quite common

What else do I still have to show from my odyssee? A yes, Leptogomphus elegans. Known from Ba Vi and from Pia Oac only in Vietnam and indeed, after seeing it in Ba Vi, I now ran into a single mail in Pia Oac.
A nice male Leptogomphus elegans. At this angle it is hard to tell, all Leptogomphids look the same, basically.

But like this is it very clear! Leptogomphids can reliably be identified on the basis of their appendages.

Still more? Yes, forgot to mention one of the few Libellulines that I took a picture of: Libellula melli. It flew at the Love Waterfall in Sa Pa middle of April and it was still there July 2. At least one male.

Male Libellula melli, nice species that reminds me of home, because it looks a lot like L. depressa.
Anything else? Yes, yet another gomphid. Phaenandrogomphus tonkinicus, found at the end of May for the first time in Xuan Son National Park, turned out to be a common species in medium sized rocky currents. I saw it many times in Bac Kan and Cao Bang provinces. Many females were seen ovipositing in Pia Oac.

This is what the female looks like, pattern much like the male

And Phaenandrogomphus tonkinicus male. Hovering for prolonged periods over the little sandy spits where the females would come to oviposit, but with terrible timing, as invariably he was there when they were not and vice versa.
And that, dear readers, concludes the report on damsels and dragons from the northern provinces in late June and early July.

Tuesday, 13 May 2014

Two Davidius species

May 11 in Yen Bai Province I was checking a stream in relatively good forest. The stream split into smaller streams, heavily vegetated with shrubs along it. In one stretch I found 4 small gomphids. I was able to get some photos and close-ups. Interestingly, these all were perched on leaves. Later on, I found superficially similar gomphids, but seemingly even smaller and with different pattern. For instance, the antehumeral spot was missing. Interestingly, the 3 specimens I saw were perched on rocks in the sun, one obilisking magnificently. Checking at home both were Davidius gomphids. Coincidentally, that is genus 100 to feature in this blog!
3 species of Davidius are known from Vietnam according to Do & Dang (2007). These are D. fruhstorferi, D. trox and D. monastyrskii. My two species fitted very well with the first two species.

Davidius trox, male

Davidius fruhstorferi, male

Davidius trox, male. Note the antehumeral spot.
Another Davidius trox in dorsal view. Perched on a leaf.
Male Davidius fruhstorferi, perched on a stone in the open
Davidius trox, appendages in lateral view
Davidius trox, appendages in dorsal view 
Davidius trox, appendages in ventral view
Now compare Davidius fruhstorferi, appendages in lateral view
Davidius fruhstorferi, appendages in dorsal view
And the same, in ventral view

Penile organ of Davidius fruhstorferi

The same of Davidius trox, actually very much not the same