Saturday, 30 November 2013

A quick visit to Van Long - The Paracercion problem*

The last several days I have been very busy with work on the one side and haunted by the Pseudagrion enigma on the other. Rory Dow suggested to look into the possibility of it being related to Paracercion impar and that is why I looked into the Paracercion article by Dumont (thank you Rory) and at the same time decided to take a closer look at the posterior view of the few specimens of Paracercion I have to see what it looks like in real life, compared to the drawings of Dumont. What a shock to find that the posterior view of the specimen from Van Long and that from Huu Lien, very similar in lateral and dorsal view, are completely different! See below first the lateral views:

The Huu Lien Paracercion species

The Van Long Paracercion species, yes there seem to be some slight differences I overlooked

But the posterior views are really revealing:

The Huu Lien specimen

The Van Long specimen
So quite a shock to find that these must to two different species, but very similar in other aspects. I work under the assumption now that the Huu Lien specimen is P. melanotum, whereas the Van Long specimen likely is (Para)Cercion malayanum.

Anyway, this is why today I drove to Van Long, to see if I could obtain a few more specimen of "malayanum". This proved difficult, as there was really not a lot going on at Van Long, even if the weather was pretty good, sunny, 22 degrees. Hardly a damsel or dragon was moving. It is strange how different the mountains in the north are compared to the Red River Deltaic area. I did see a few things of interest though, and I did collect two more males. Hopefully there will be success at Huu Lien too, tomorrow.*

* Note that I found the female of P. melanotum in Huu Lien (see the post on that subject), but I also took photos of the posterior view of the appendages of the Van Long new specimens after this post, that throw a different light on the subject. See the post: "Paracercion continued."

Here is a photo of a male perched on a floating leaf.

Paracercion cf. melanotum (explained in post "Paracercion continued"), male 

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