Not a Bao Loc specialty - Heliogomphus chaoi

Karate (2004) described Heliogomphus chaoi from Bao Loc in Lam Dong Province in the south of Vietnam. This species is very similar in appearance to Heliogomphus selysi, a species occurring in for instance Thailand. H. chaoi differs especially in the shape of the vulvar scales of the female and the lack of prominent spines on the occipital ridge. In stead it has two small horns behind the lateral ocelli. Karube also notes that the superior appendages have a ventrolateral projection at the midpoint, to separate the male from H. selysi. Indeed, Asahina did not mention this for H. selysi, but I would love to see the holotype to verify this.

Anyway, last year I found this species to be common near Bao Loc at the type locality in early June. But a few days later I bumped into another small Heliogomphus in Gia Lai Province. Outward it was a little different in coloration. Notably, the superior appendages were more extensively white and S7 had a distinct anterior pale yellow ring. With differences between Heliogomphus species often slight, I thought it might be a different species, but checking it under the microscope I cannot but conclude the appendages and vesica spermalis are identical. If so, the slightly different coloration is likely nothing but a geographical variation. I concluded that the Gia Lai specimen is also H. chaoi. That species is therefore much more widespread than previously thought.

Heliogomphus chaoi in Bao Loc. Note it only has on S7 a pale yellow line along the dorsal carina and a lateral basal spot.

Another male at the same location

And the appendages in dorsal view

Heliogomphus chaoi at Gia Lai. Note the small yellow dorsal spot on S8 and the large anterior yellow ring on S7. But structurally it is not different.

The appendages in dorsal view, the white more extensive

Heliogomphus retroflexus - about time

On May 10 I was checking a stream in central Ha Tinh Province when I noticed a freshly emerged gomphid landing by the side of the stream. I quickly made a few shots and checking them in preview it dawned on me that this must be Heliogomphus retroflexus. This is a species with a wide range, across Mainland China, Taiwan, Hainan, and south to at least Lao PDR and northern Vietnam. In fact the type was collected in Tonkin. But I had not seen it and was keen to do so, after it recently had been recorded from the Tam Dao mountain range by Natalia von Ellenrieder and colleagues. To find it relatively far south possibly extended its range. The stream I found it at ran through heavily disturbed woodland and plantations.

To my big surprise I ran into it again in Xuan Son on May 30, and not just one or two, but at least 10-15 individuals, all taking refuge from the heavy sun along the karst cliffs in the forest along the main stream. Not only several males and females, but also several copula were chilling there. It is not a difficult to recognize species, with the characteristic appendages of the male and the ringed abdomen. Strange to find it in such numbers in a place extensively surveyed last year.

Male Heliogomphus retroflexus. Apologies for the bad angle. They all tended to sit higher  up.

This female was more obliging

Not to speak of this very kind copula. 

This is the male in hand. Note the bulging lamina.

The appendages in dorsal view

The female, similarly ringed and with a golden wash to the wing bases. Note also the curvy hind femora.

The original teneral male from Ha Tinh. The ringed abdomen is already apparent.

Eventful day at Tay Thien, a few more goodies

This weekend (June 15-16) proved pretty productive at Tay Thien. Apart from the species already described, I encountered about 50 more. Here are a few other highlights

The first was this beautify male Polycanthagyna erythromelas. I saw several females flying about, but this male resting for a short while in a nearby bush was a treat.

And in the lower river stretches were several Lamelligomphus formosanus active. Once you know the species, it is not so confusing anymore.

Another species present in good numbers, towards the evening in the open and during the day in dark clearings, was Macromidia rapida. I was lucky with a male that perched nearby.

The female of Sinorogomphus sachiyoae. Very much like the male in appearance. After these shots she happily continued ovipositing.

Another cool female, Heliogomphus scorpio. The male was active nearby as she was ovipositing near the nunnery. Like the male, very pale (white) metepimeron, unlike Heliogomphus sp., which occurred at the same stretch, but is much yellower.

Here a close-up of her pretty face. Note the horn on the occipital ridge.

There was something else I did not expect, Drepanosticta hongkongensis. I noticed a male at 350m asl beyond the nunnery. Under the microscope it is identical to the specimens from Ba Vi. I thought the species there was known only from that location in Vietnam, but when this is D. hongkongensis, well, in that case it is not surprising it occurs elsewhere. Although the caudal appendages are identical, the anterior lobe of the prothorax is all black, as it should be for D. hongkongensis, unlike the specimens from Ba Vi.

The penile organ, identical

As are the caudal appendages

The Heliogomphus enigma

When exploring around Nam Bung earlier this month I saw quite a few Heliogomphids that I identified as Heliogomphus scorpio based on the shape of the (all black) appendages. In fact, Sebastien Delonglee also had identified this species as such (see also his blog). However, when checking streams low on the Tam Dao range last weekend I noticed that the appendages of the Heliogomphids there seemed different. Interestingly, Sebastien during his visit to Xuan Son noticed the same. I asked Dr. Karube and he told me he was aware of two different types of Heliogomphus, but that apart from the appendages the species were very much alike. Nevertheless, we all agree that these actually are two different species. The identity of the Yen Bai type, in fact that also occurs around Tam Dao, is unknown for the moment. The species I encountered at Tam Dao now (and Sebastien at Xuan Son) is the real Heliogomphus scorpio.

The Yen Bai Heliogomphus, very yellow and long appendages

The Tam Dao Heliogomphus scorpio, much paler and different appendages

The appendages in dorsal view of the unidentified species

Those of the Tam Dao Heliogomphus scorpio. Both superior and inferior appendages are differently shaped

The unidentified species, note the double tooth on the basal process

The same for Heliogomphus scorpio, a much longer process, but no double tooth

Three more Gomphids from Yen Bai

Gomphids - I love them! So, when I spent last weekend in Yen Bai, I was a happy man, seeing 6 new species. In fact, one I had seen before, but this is the first time I had an adult in my hands. It is a species of which Sebastien already told me that it was quite common. I have seen it freshly emerged at low altitude in Tam Dao and here it was again higher up in Yen Bai Province. It is a Leptogomphus that looks very closely like L. perforatus, but has inferior appendages smoothly rounded. The hamules are also quite differently shaped, especially the anterior one.

The other two species, well…The first I saw about 6 of. It is an easy species to recognize, or so I thought, and it appears in quite open areas on wet rocky and muddy places, where is sits on the ground, on rocks or on leaves. It was a Heliogomphus and I did identify it as H. scorpio, but subsequently I caught several H. scorpio in Tam Dao and clearly it is a different species. I will come back to this in another posting (this part of text edited May 18). And I saw one interesting gomphid with slender white superior appendages that I subsequently identified as Sinogomphus leptocercus. This is quite a shock, as to my knowledge it is only known from Xizang, Tibet, although close to the Yunnan border. And admittedly the thorax pattern is darker. On the other hand, within Sinogomphus, this species is strange because of the thin and long superior appendages and broad inferiors. Moreover, the penile organ is also a close match. If not this species, than it is something very closely related but as yet undescribed. Unless, of course, someone has a better suggestion.

Sinogomphus leptocercus, male

The penile organ. Compare the drawings in Chao (1990)

The weird appendages in dorsal view

In ventral view

And finally in lateral view

Leptogomphus sp., as far as we have been able to check, undescribed but common.

The appendages in dorsal view, note the smoothly rounded shape

The same in ventral view

The hamules in lateral view, compare with those of L. perforatus below

Hamules of Leptogomphus perforatus for comparison

And finally male Heliogomphus sp.

Perched on a leaf, an easily recognizable species (May 18 edited: not at all that easy, this is not scorpio after all)

The appendages in dorsal view, see also posting on H. scorpio and differences