Tuesday, 9 September 2014

Yen Bai - Aeshnid headache*

Last weekend was great weather, so I decided to drive the Yen Bai and check out the autumn status of things. On Saturday I visited Xuan Son and saw a great many old friends, but nothing I had not seen before. I drove on in the evening to Nghia Lo and stayed in the local hotel, drove on the next morning to the general Yen Bai area. At one of the first stops around 10 AM I caught a beautiful Anotogaster, on which more in the next post. I then around noon checked the trail and stream at the fish farm and motel. There was not really a lot going on, although Anisopleura were plentiful. But in one shaded part of the trail (less shaded all the time because of tree cutting) I saw an Aeshnid that after a short flight over the trail hung up in the trees. With some very careful climbing I was able to get to it without disturbing it. Examining the specimen it appears to be a Cephalaeschna, judging from the venation and the number of cells in the anal triangle. Also, a broad frons. The appendages are blunt, but not rounded, in fact they display a small point. There are quite a few Cephalaeschnids in China, but only a few have been recorded for Vietnam. I am aware of C. aritai and C. asahinai and recently Sebastien caught something close to C. klotsi. The facial markings of my specimen are very close to that described by Karube for C. asahinai, but it has a small apical tooth to the appendages that should be absent in the rounded appendages of C. asahinai. I am still waiting for the article by Asahina (1981) with the exact description of C. needhami, but appendages ( long inferior, slightly pointed superiors) and facial pattern apparently match. It cannot be ruled out this is a completely new species, but for the time being I will consider it C. cf. needhami. Any suggestions more than welcome!

Up in the tree, Cephalaeschna. Note the greenish markings and the reddish femurs. 
In hand, reddish legs obvious, as is the long epiproct.

In dorsal view, note 5 celled anal triangle and small pterostigmata

Facial pattern with yellowish-red labrum, greenish yellow postclypeus, antefrons dark reddish brown with greenish lower margin.

Appendages in dorsal view. Note that they are not rounded, if blunt, with angular corner,. Epiproct two-thirds of superiors. 

Lateral view of the same
Ventral view. Again the corners not rounded.

Penis in lateral view. Flagella longer than apical segment, double

Penile organ in ventral view
*Haomiao Zhang commented that this species is indeed close to C. needhami (and C. klotsi), but that it is neither. It could well be a new species.

2 comments:

  1. Very nice discovery! Wonderful species.

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  2. Hi Benoit, yes indeed, but the Aeshnids keep on posing major problems. So many species around and so little known about them, nor information on their appearance. In this case, some specialists consider this typical needhami, others that it is not that species, but related. There is no easy reference. In fact, exactly why my head hurts...

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