Gomphidictinus tongi, a wonderful discovery from Vietnam

In May 2016 I observed, but could not catch, a large Gomphidia-like gomphid in pristine forest just south of Phong Nha - Ke Bang National Park in Quang Binh Province in Central Vietnam. I thought it might have been Gomphidictinus kompieri, because of its deep forest habitat. I visited several times later in the season, but it rained every time and so I did not see it again. But this year I visited in early June and was more lucky. Not only did I catch a male, I also found the species next to the botanical garden of the National Park. And it clearly was not G. kompieri. It was a new species for sure, judging from the shape of the appendages, coloration and wing venation.

Not long after I was contacted by Zootaxa regarding a manuscript for a new Gomphidictinus species from China by Haomiao Zhang and colleagues. And what a surprise when this turned out to be exactly the same species: Gomphidictinus tongi Zhang, Guan & Wang, 2017. This lead to an interesting debate regarding its genus. Although the species is currently included in Gomphidictinus, in the same manner as G. kompieri was included in it, on the basis of the spine on the vesica spermalis, differentiating between Gomphidia and Gomphidictinus is not straightforward, not on the basis of this spine, nor on the basis of for instance wing venation. An overhaul of the genera, including DNA-analysis, is needed to solve this, but for now this fabulous dragon is included in Gomphidictinus as the third member of that genus.

Some unidentified Gomphidia / Gomphidictinus reported from Tam Dao by Natalia von Ellenrieder likely also concern this species, which therefore may be more widespread in Vietnam, apart from ranging widely in China (now recorded from Guangxi and Hainan). Interestingly, the two male specimens from Vietnam in below pictures indicate some variability in the maculation of the abdomen.

Female of Gomphidictinus tongi. It has wide flaps to S8, although not so visible here

Typical male showing already striking yellow markings compared to the two other species in the genus.

Slightly overexposed, so not as yellow, second male, but note extensive marking of S6 compared to the first.

Gomphidictinus perakensis

Fraser erected Gomphidictinus as a separate genus from Gomphidia based on the ventral spine on the penis. Until I found the as yet undescribed new species sharing this characteristic, Gomphidictinus had only one member species, Gomphidictinus perakensis. It has been questioned whether the spine on the penis warrants separation from Gomphidia. Apart from this character, the species looks very much like other Gomphidia species.

According to the IUCN website, this species occurs widely in Malaysia, Thailand and Laos and a specimen of unknown exact provenance, but from Vietnam, is kept in the collections of the Natural History Museum in London. Karube (2014) mentions two records from 1996 and 2003, both from Lam Dong in southern Vietnam. According to him, these are the first records for Vietnam. These two statements appear contradictory. Karube assumes that G. perakensis only occurs in southern Vietnam. However, I saw one male on a stream in northern Bac Kan Province on June 22, 3 males on a different stream also in northern Bac Kan Province on June 25, and on July 7 2 males at a stream approximately 25km from these locations in southern Cao Bang Province. Clearly the species occurs right up to the Chinese border in Vietnam.

Male Gomphidictinus perakensis, June 22 Bac Kan Province

Another male in hand on June 25, also Bac Kan Province

Another male, July 7 in Cao Bang Province

Frontal view of the face 

Dorsal view of thorax

Distinctive appendages in dorsal view

And in lateral view

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)