A new species of Asiagomphus*

*Updated January 1, 2020 based on the publication in 2018 in Zootaxa of my study of the genus Asiagomphus in Vietnam, which included the description of this species as Asiagomphus kosterini.

April 17 I was checking streams near Tuyen Lam Lake at Da Lat. It started as a sunny day and around 9.30 I spotted the first gomphid, perching in the middle of the stream on a stone. It was immediately obvious from the extensive yellow on the terminal segments that this was something I had not seen before. It took some effort, but eventually I was lucky enough to be able to net it. In hand my suspicions that it was an Asiagomphus species were confirmed. A very interesting species, with extremely extensive yellow markings and widely expanded S7-9. Patterning was otherwise in line with Asiagomphus and the appendages were also typical of the genus. But it is not any of the other 4 species (at least) I have seen in Vietnam and it is not any of the known species from South-East Asia either. A wonderful species and new to science! It was rather common at the stream, with at least 10 different males observed and a few females seen ovipositing.

I eventually published this species as Asiagomphus kosterini, one of a total of eight species of Asiagomphus I could confirm in Vietnam.

Asiagomphus kosterini. Note the extensive yellow markings on S7-9. A beautiful and striking species.

A male in dorsal view, showing the massive club

And in lateral view

The appendages and terminal segments in dorsal view