Three species of Leptogomphus at Tam Dao

The weekend of 17 and 18 May I spent at Tam Dao. At the lower river stretches around Tay Thien I encountered many Leptogomphus. I already mentioned L. perforatus and a second species, L. divaricatus (now identified thanks to Haruki Karube). Cuong mentions also Leptogomphus gestroi from Tam Dao. And Sebastien has photos of yet another Leptogomphus, likely L. elegans. So, I take care with any Leptogompids I come across. They all look very similar superficially and should be looked at in hand. I thus caught yet another Leptogomphus and saw very different lower appendages. It allowed for easy identification as another species: Leptogomphus tamdaoensis, soon to be published by Haruki Karube (thank you for your comments, Karube-san!).

Here are the three different species. It is immediately clear that these are all rather similar. L. divaricatus is at the top. This is a slightly larger species. L. perforatus is on the left whereas L. tamdaoensis is at the right bottom.

A very sad turn of events was that this nice insect got its jaws entangled in the net and was sadly decapitated. The pattern on the thorax is basically identical to that of L. perforatus.

The difference between these species is thus in the appendages and the apparatus of S2. I already once showed those of L. perforatus and L. divaricatus, but I add them here (of different specimens) once more. They are consistent in their differences. But let's start with Leptogomphus sp. novum.

Very distinctive shape of Leptogomphus tamdaoensis

Compare the stubby boot shape of L. perforatus

And the nicely rounded sock shape of L. divaricatus. Note that this specimen is slightly disfigured, with the left lower appendage bent.

The hamules, with the anterior very long and the posterior not hooked in lateral view, of Leptogomphus tamdaoensis

Those of L. perforatus

And those of L. divaricatus