Monday, 12 October 2015

So does Planaeschna guentherpetersi occur in Huu Lien or not?

On December 1, 2014, I caught a female Planaeschna in Huu Lien that seemed to be a P. guentherpetersi, complete with the typical dorsal and lateral pattern on S2. Please see the concerned post. The facial pattern however was much more vivid than anything I have ever seen in Xuan Son, where the species is quite common. So, when I discussed with Haruki Karube a little while back we decided that it was not likely these two were in fact the same species. But I had no material from Huu Lien for comparison (I may have released the specimen at the time, or it was eaten by vermin, anyway, I do not have it), so it was/is undetermined. I had a single specimen last year that flew off. Finally yesterday I noticed an Aeshnid in the dark of the forest flying about. It hung from a twig, but I could not get to it, so decided to make some pictures with flash. These made it clear is was a male, and that it was a Planaeschna for sure. It also has the same dorsal pattern as the female on S2. Interestingly, the pattern on the remainder of the abdomen and on the lateral side of S2 is the same as in P. guentherpetersi. The shape of the appendages, insofar as can be judged from the pictures is not at variance with that of P. guentherpetersi either. Although the fact remains that the female has quite a more pronounced facial pattern, it seems for the time better to assume this is a local variant than enough grounds to claim this is a different species. But of course, I will try to catch it at the next occasion. It would be great to sample the populations for DNA.

The enlightened photo of the Huu Lien specimen, showing the typical dorsal pattern of S2 and remainder of the abdominal pattern. Compare with the below scan of the Xuan Son male.
The Xuan Son male. Planaeschna species have a lot of variation in the pattern of S2 or the abdomen, so for these specimens to very similar is likely too much of a coincidence.

The Huu Lien male at a different angle, showing the intense green and black thorax pattern and the lateral pattern of S2, with the yellow auricle and two spots on the distal edge.  This is very much the same pattern as can be seen in the scan below.
See the pattern of S2 on this male from Xuan Son. No other species in Vietnam, out of the other 9 or so I have found, has a similar pattern, but the specimen from Huu Lien has it. See also the heel on the ventral side of the superior appendages, visible in both the scan and the photo. For what it is worth, of course.

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