17 and 18 August I spent happily navigating my way along the streams of Tay Thien in Tam Dao National Park when I noticed a large Gomphid perched along a rocky surface several meters above the stream. This cliff was very wet and dripping, the place deep in the forest. It looked like Gomphidia kruegeri, but the location was very different from the habitat I had encountered that species in in Ba Be. I managed to get a few shots of it, although not very good. The next day, I found another male, on the same stream, but several hundreds of meters removed. This time I could catch it for in hand examination. To my disappointment the appendages looked very much like those of G. kruegeri and as all other Gomphidia are rather different, I dismissed the possibility of it being something else. However, when checking carefully the photos I took at home, a creeping suspicion occurred to me. I had collected this last specimen, so decided to have another look, because on the photos the shape of the antrior lamina seemed different and the pattern on S3 was also quite different. It may well be that G. kruegeri is rather variable, but the differences I noticed do warrant more attention, especially as the individual I took pictures of the previous day displays the same characteristics. For comparison I include also photos of G. kruegeri. The reader can decide if this could be a variation, or something else.
|The facial pattern of the Tam Dao specimen|
|The facial pattern of the Ba Be Gomphidia kruegeri|
|Superior appendages Tam Dao specimen|
|Superior appendages of G. kruegeri|
|The Tam Dao specimen|
|The Ba Be G. kruegeri|
|The genital lobe of the Tam Dao specimen, note also the black ventral side of S3|
|The genital lobe of G. kruegeri.|
The genital lobe of G. kruegeri has a characteristic hook at the tip and a round distal profile. There is some variation between the subspecies. The genital lobe of the Tam Dao specimen has a more triangular outline and the hook is absent.
|The dorsal pattern of the thorax of the Tam Dao specimen|
The dorsal stripe is not connected to the antehumeral spot, as is typically the case in G. kruegeri. In that respect it looks like G. perakensis (from which it differs in many other respects).
|Not too sharp photo of another Tam Dao specimen|
|Another photo of the same specimen as in the previous photo|