Asiagomphus pacificus - finally (a lot of) males

*This entry was updated June 25, 2018. New insights into the differences between A. hainanensis and A. pacificus now lead to the conclusion these are A. pacificus.

May 19 I was checking a river close to Cao Bang city when I ran into at least 10 males of Asiagomphus pacificus. This species I discovered new for Vietnam last year at Bac Kan at a site that has since been destroyed. What is more, I only found one single female, leaving room for discussion. But these males are very obvious and also show that this is certainly a species that is more widespread in northern Vietnam.

There are at least 4 species of Asiagomphus in Vietnam, but the problem is species of this genus are very similar, both in outward appearance and in appendages. The easiest is arguably Asiagomphus acco, with its dorsal tooth on the superior appendages. Asiagomphus sp. novum is also relatively simple, with the epiproct V-shaped, see the entries. Asiagomphus auricolor is apparently rather variable. I also consider it a candidate for what currently is identified as A. xanthenatus in Laos. A. auricolor has sometimes two and sometimes three lateral stripes and the female more or less yellow on S1-2. A. pacificus has longitudinal stripes on the dorsum of the abdomen, quite different from the rings of the other three. It also often has a spot on S8, which really helps the ID.

Asiagomphus pacificus, finally a male. Note the oval lateral spot on S8. The humeral stripe can be much clearer.

The same male at a different angle. Note the longitudinal markings along the dorsum of the abdomen, all the way up to S7.

Another shot of the same male

A different male, without the oval spot on S8 and with more extensive humeral stripe.

Macromia number 9, M. katae

This January Natalia von Ellenrieder, Martin Hauser, Stephen Galmairi and Thai Pham published on article in Check List on field research carried out in Vietnam. Of course I carefully perused it and was astonished to read about a new record for Vietnam of Macromia katae not far from Hanoi. Both myself and Sebastien Delonglee set out to find it, but at my visit earlier this year it was probably far too early. But Sebastien was more successful towards the end of May or early June and finally I myself found time today to go to the location. It was mostly very cloudy, but I was lucky enough to almost immediately spot a Macromia cruising up and down and even more lucky to be able to net it for verification. Indeed, it was Macromia katae. Although sharing some characteristics with M. unca, like yellow antehumerals and an obvious spine on the dorsum of S10, it was immediately obvious from its largely blackish face that it was M. katae. Check of the hamule and genital lobe confirmed the ID. In Europe we are happy with one Macromia, in the US with a few, but Southeast Asia has an abundance. This is my ninth species for the north of Vietnam and they are all just simply fantastic.

M. katae is a rather rare species, virtue of the scarcity of its lowland habitat, as explained in the Check List article.

Macromia katae, a beautiful Macromia. Note the darkened wing bases.

The face is very dark, with small yellow markings on labrum, base of mandibles, and postclypeus.

The dorsal spine on S10 is very prominent

The epiproct is quite long, extending well beyond the superiors

Typical hamule and lobe. What I found striking is that the genital lobe is bicolored.

Adventures of Floris Brekelmans on Phu Quoc

A fellow Dutch naturalist, Floris Brekelmans, visited Phu Quoc in April and recorded some interesting Odonata there. Below is a short report of his on the most spectacular find: Podolestes coomansi, which is an addition to the Vietnamese list.

Quote:

During a three day visit from 11-13 april 2015 to the island of Phu Quoc, I had the opportunity to explore some of the forests and streams in the northern part of the island. These forests are part of the Phu Quoc National Park, which consists of upland primary forests, primary dipterocarp forest, secondary forests, mangrove forests and melaleuca forests. Parts of the latter have been recently turned into palm-plantations and are threatened by other types of cultivation, forest fires and development of touristic settlements. Access tot the Phu Quoc National Park is restricted and only few tracks lead into the forest. One of them is the popular forest walk near to Ganh Dau village, on the north western part of the island. Geen beste kwaliteit, het viel niet mee te fotograferen zonder flitser in het donkere bos.On april 12 I visited the northern part of the National Park, in the surroundings of Ham Rong mountain. 

This forest is accessible by the K7 road to Rach Tram village. Just after crossing the melaleuca forest and at the beginning of the dipterocarp forest, I went off the K7 road in reach for the north-eastern slopes of the Ham Rong mountain. The secondary forest (tree height 10-15 meters, indications of selective cutting, poaching with nets) at sea level is accessible by several foot tracks and - in the dry season - the dry beds of the small seasonal streams leading to Ham Rong mountain.  

Dragonflies were far from abundant, in numbers as well in species. The following species were seen and photographed at the locality: Brachythemis contaminata, Copera marginipes, C. vittata, Lathrecista asiatica, Libellago hyalina, Neurothemis fluctuans, Orchithemis pulcherrima, Podolestes coomansi and Vestalis gracilis. Both Copera species appear to be are new to the island (based on Do et al 2011) and Podolestes coomansi is a new species to Vietnam. This species has recently been discovered in four provinces in Thailand and was formerly only known from the type locality in Malaysia. Lieftinck (1954) and Kosterin & Vikhrev describe the habitat as marshy spots in secondary forest or narrow patches of trees separating wide swamps. On Phu Quoc I found it in a dry bed of a seasonal stream in thick secondary forest. Melaleuca marshes - dry in this time of year - are present at a distance of 500 meters southwards. Kosterin & Vikhrev suggest the larvae of the species may tolerate seasonal drying of the habitat.

Unquote

Podolestes coomansi male, courtesy of Floris Brekelmans

An exciting new Chlorogomphus and an old acquaintance

When I met Haruki Karube on May 2 at Mau Son mountain he had just explored streams in the Central Highlands in Da Lat. He was kind enough to show me a specimen of the beautiful Chlorogomphus caloptera, which he described as recently as 2013. A female, and that is a beautiful creature.

Never mind the hand, focus on the wonderful wing pattern of this female Chlorogomphus caloptera.

The same female in lateral view

And her face in frontal view

On May 9 I was in Ha Tinh Province, not quite Da Lat, but the south of the north, if you catch my drift. In the lowlands I visited a stream with Toan when we discovered a female Sinorogomphus. In hand I could identify it as S. sachiyoae. This is another species described by Karube, but much longer ago, in 1995. Although originally thought to be restricted in range, it has now been found from Cao Bang Province all the way south to Ha Tinh Province, making it one of the more wide-spread species.

Sinorogomphus sachiyoae female. Note the characteristic pattern on S1-2. They do not always have such extensive basal patches, although it is not abnormal.

Burmargiolestes melanothorax - easily overlooked

According to the IUCN website Burmargiolestes melanothorax is not uncommon and occurs in hill forest from Myanmar to Vietnam. Do & Dang indicated records from Lai Chau, but I had never seen them anywhere, until I finally caught up with the species in Ha Tinh Province, in hill forest close to the Laotian border, on May 9. If you do not pay attention to the appendages and abdominal tip, it is easily overlooked, because it inhabits the same kind of habitat as Agriomorpha fusca and looks a lot like that species, with its blackish thorax and ringed blackish abdomen and yellow face. It does however not have all-white S9-10 like A. fusca and that should be the give-away. Inside the forest where I saw it, it was not uncommon and shared its habitat with Devadatta cyanocephala, Protosticta satoi, and the same Drepanosticta sp. novum that also occurs on Ba Vi Mountain.

Burmargiolestes melanothorax male at Ha Tinh Province

Another male. Note the white half-ring between S8-9 and S9-10.

Fukienogomphus complete

On April 19 I caught a male Fukienogomphus prometheus in Huu Lien. In the post on that species I also mentioned F. promineus, a quite a bit larger and more robust species in the genus that so far I had not seen. But it had been described for Vietnam already by Do Manh Cuong and it also features in the blog of Sebastien. It was recorded from Tam Dao and from Mau Son. The Vietnamese specimens found so far are darker than the specimens from China. In fact the second lateral stripe in these records from Vietnam is reduced to just two small spots.

On May 18 I caught a large gomphid close to Tu Le in Yen Bai Province. It was immediately obvious this was Fukienogomphus promineus, even if in stead of two it had three small spots for second lateral line.

Male Fukienogomphus promineus, a large gomphid

Its appendages in dorsal view

And in lateral view

A very common face

 When writing about F. prometheus I mentioned Haruki Karube had recorded it from Cuc Phuong. I visited that place on May 22. And ran into a handful of F. prometheus, including females. They frequented small forest streams.

Fukienogomphus prometheus, male, perched after release.

A different male F. prometheus. Significantly smaller than F. promineus and with complete second lateral stripe.

The female is very close to the male in appearance

And had distinctive cerci and epiproct

Bayadera species - more confusion

Over the last few weeks I was lucky enough to find at least 5 Bayadera species. I already posted on Bayadera continentalis at Pia Oac. In the meantime I have also been able to capture a female, on May 20.

Interesting pattern with heart-shape laterally and a large elongated spot over the humeral suture. Bayadera continentalis female

Scan of the same female, displaying a distinct brownish wash to the wings

The next species that caught my attention was Bayadera nephelopennis, which apparently is not uncommon in the Sa Pa region. This species can easily be confused with Bayadera bidentata. Both have blackish males with a little pruinosity. B. bidentata is somewhat smaller and the females are in fact rather different in pattern, as I hope to show further on. Anyway, on May 18 I saw both a female and a handful of males in Sa Pa and again several males and a female on May 25.

Female Bayadera nephelopennis in hand

The dorsum of the thorax is quite distinctive. It has broad lines along the dorsal carina, but nothing over the humeral suture.

Another female on May 25

A male on May 18, showing the quite unicolorous appearance

But a pretty face, although this pattern seems shared by many species

 On May 25 I spotted yet another species at Sa Pa that I identified as B. hyalina. However, it does not have dorsal lines on the thorax and several other characteristics of a species. Whether that is an indication of variability or indicates a possible different species needs to be resolved at some stage, preferably through DNA analysis.

Bayadera hyalina (or possibly closely related species?)

Scan of dorsal aspect

 On May 23 weather was cloudy over Pia Oac, so I checked a stream further down and bumped into a whole bunch of Bayadera serrata.  A female in tandem showed herself fleetingly and was quite yellow, but I could not get a photo of her.

Bayadera serrata, male. A beautiful and distinctive species

Brightly coloured thorax and face

And distinctive bird-beak appendages

And finally the last species was Bayadera bidentata. Surprisingly this species showed up with several males and females at Xuan Son on May 30, where we had completely failed to see it previously!

Male Bayadera bidentata, with quite a bit of pruinosity on the thorax contrasting with the black dorsum

The usual pretty face

The female B. bidentata is rather different from B. nephelopennis. It has an irregularly shaped marking over the humeral suture, which is lacking in that species, and reversely misses the lines along the dorsal carina.

 Not to make this posting excessively long, I will publish the differences on the appendages between these species in another post.