Sunday, 18 May 2014

Bayadera bidentata - a nice find at Tam Dao*

*This entry was first published as B. nephelopennis, but this was a mistake. It was adjusted on December 23.

18 May I went to Tay Thien in the Tam Dao mountain range. It was a very hot afternoon and really quite productive. On the way back, between the little shrine in the valley at the foot of the big climb to the temple and the monastery, I noticed a damsel sitting on a twig by the path that in general proportion and cloud reminded me of Devadatta ducatrix, but that species has black wingtips and this one did not. It also had a blue face and in hand the appendages were like Bayadera. It was only later in the year and with the help of Toan that I could settle the ID: Bayadera bidentata. An interesting species with its pruinosity. Although I first thought it was B. nephelopennis, that species has different appendages. The inferiors for instance are quite a bit longer. B. bidentata had been reported from Tam Dao by Karube (1994).

In hand, blackish thorax with pruinosity obscuring yellow lines, black abdomen, blue face

Close-up of blue face

Vaguely smoked brownish wings


  1. Awesome record, especially at Tam Dao, the place the most visited by odonatologists / odonata lovers in Vietnam!
    I guess it is a retiring and inconspicuous insect, certainly not easy to find in the future. But at least we know it is here.

    Keep up the great work, 2 or 3 new species for the country checklist every week,that`s not bad ;)

    1. Hi Sebastien, yes, I found it not on the stream, but in the forest about 10 m away from the water, perched along a narrow trail. If it is a middle altitude species, that might explain how it was overlooked. Visiting specialists have invariably searched around Tam Dao village at 1000 m asl. Mind you, remember Zygonyx asahinai? Although we found it as Tay Thien last year, I also caught it now at Tam Dao village, so it has been overlooked there for sure. Just makes you wonder how much more there is to discover!