Sunday, 4 May 2014

A new species of Gomphidictinus*

*Adjusted June 1, 2016. This species now published by Karube as Gomphidictinus kompieri. I am really happy with this massive species.

In 1942 Fraser, and right now I do not have the article, so if you have it please send it to me, erected Gomphidictinus for a species in the Gomphidia group with a spine at the base of the apical segment of the penis. Otherwise Gomphidictinus wheeleri, later identified as a junior synonym of G. perakensis, is very much Gomphidia like, although it is very large.

Last year I mentioned a weird Gomphidia from Tam Dao that lived deep in the forest. May 3 I was lucky enough to encounter at least 6 in Xuan Son National Park, all on a stretch of a shallow clear stream under heavy forest cover. I was even more lucky in that I observed 2 females of which I collected one.

Under the microscope the male has the spine of Gomphidictinus, interesting, as G. perakensis is a deep forest species too. It has many differences in color pattern, however, and the female is strikingly different (in G. perakensis S2 is completely yellow, for starters).

It is also a massive insect. Asahina gives abdomen (including appendages) 52-56mm for males G. perakensis, and female 51-52mm. Laidlaw (1902) gives total body length 78mm, already very large. However, my specimens from Xuan Son have the following measurements: Male (2) TL 86-88mm, Abdomen (+app) 64-66mm, HW 57mm, Pterostigma HW 7.5mm. Female (1) TL 90mm, Abdomen 64.5mm, HW 63mm, Pterostigma HW 8mm.
(The Tam Dao specimen was more moderate, with 82mm TL and HW 52mm)

As you can see in the accompanying scan, it dwarfs G. kruegeri, already a large dragonfly. What is further interesting is that it is very pale, not yellow, and that it is very dark. The postclypeus is completely dark, differing from G. perakensis and the female has interestingly a completely unexpected shape to the occipital ridge.

On the left Gomphidia kruegeri, a large dragonfly, and the right the Gomphidictinus species novum, a truly ginormous dragonfly
The male face, with all black postclypeus and labrum

The female face, similar to the male, but note the occipital ridge, quite the opposite of G. perakensis

Note the spine at the base if the apical segment, typical of Gomphidictinus (if a valid genus)

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