Thursday, 10 October 2013

Pseudagrion pruinosum, Pseudagrion microcephalum and Pseudagrion sp.*

The other day I did a little entry on Pseudagrion rubriceps and P. australasiae. This late summer produced three more Pseudagrion species. One is relatively large and striking, with red eyes and a darkish body and abdomen, without clear blue colors. This is P. pruinosum. The others are much less straightforward. One looks very much like its brother P. australasiae, but has longer appendages. This is P. microcephalum. The third looks somewhat like both P. australasiae and P. microcephalum, but it also resembles for instance Paracercion malayanum. From all three it can be distinguished on the basis of a combination of characteristics, both in coloration and appendages. The females of this latter species are rather different from the other Pseudagrion species and could be confused with either P. malayanum or Ceriagrion females. At first I was under the impression that this in fact was P. microcephalum, until I noticed the females are strikingly different from the females shown in for instance the blog by Dennis Farrell on Dragonflies in Thailand or in the literature from Japan and Taiwan. Over a huge area the female of P. microcephalum looks consistently different from what I had found here. This triggered me to look more closely at a P. australasiae I saw near Cuc Phuong and I am now convinced that was in fact P. microcephalum, based on the appendages. But if that is the case, than what is the third species? If indeed it is Pseudagrion at all. We saw it in Ba Be National Park in late July and early October a female close to Van Long Nature Reserve. All suggestions are welcome.*

* Subsequent literature research helped identify this species as Pseudagrion spencei, a widely distributed species, but unknown from Vietnam.

Pseudagrion pruinosum, male
Another male P. pruinosum
And Pseudagrion pruinosum, female, in tandem
Pseudagrion spencei, male. Note the long appendages and thinner antehumeral, the all dark dorsum of S2 and greenish laterals to S3-S7.
Another male, at Ba Be National Park
The give away copula, the female very different from what was to be expected for P. microcephalum, very plain and Paracercion like 
Pseudagrion spencei, female from close to Van Long
Pseudagrion spencei, female from Ba Be National Park
The very long, but Pseudagrion-like appendages of the Pseudagrion spencei, male
Pseudagrion microcephalum, male, near Cuc Phuong
The appendages of Pseudagrion microcephalum, male, caught close to Cuc Phuong National Park.
Pseudagrion australasiae, male, from Van Long
Appendages of Pseudagrion australasiae, male, from Van Long

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