VietOdonata: Some Nice Stuff Not Far From Hanoi

Nice stream at Tây Thiên

Below are a few of my recent finds at 3 different sites around Hanoi, all at c. 75km from the city center : Tây Thiên (first slopes of Tam Dao), Mt Ba Vi and Cuu Thac-Tu Son (a tourist area in Hoa Binh Province with nice streams and waterfalls).

Three amazing places and only 1.5 hrs drive (by scooter) from Hanoi! Not easy to pick up new species for my personal records but always nice photo opportunities - so I am never disappointed.

Photos taken in May-June.

Periaeschna magdalena, male, Ba Vi
Spotted this species at Ba Vi and Tam Dao, from the lower slopes to 900m

Periaeschna magdalena, female ovipositing at a mossy wall near the road, Ba Vi

Drepanosticta sp., Ba Vi, two males engage in agonistic flight
The brilliant blue patch at the tip of abdomen make this species easy to find in the darkness of the forest

Drepanosticta sp., male, Ba Vi, yet to be described
I bumped the first time into this all-black thorax Drepanosticta in 2011, at Ba Vi, in montane forest (900m asl). Subsequently, I found it at lower elevations (300m) in this mountain but also 50 km further south, at Cuu Thac -Tu Son (Hoa Binh Province), in submontane forest.
Recently, at Ba Vi, Tom Kompier discovered that the very similar Drepanosticta hongkongensis share the same streams that this unknown Drepanosticta (but apparently earlier in the season, before the rainy season), making things more confusing... but more exciting! Drepanosticta hongkongensis (first record for Vietnam) do not show blue markings on prothorax and have different appendages (see Tom's blog entry).

Same, close-up showing the blue markings on protorax (in both sexes). Note also the blue mark at the base of wings

Protosticta satoi, male, Ba Vi

Same, close-up

Protosticta satoi dark morph, male, Tây Thiên

Leptogomphus sp., Tây Thiên
Copula caught by a robber fly (Asilidae)

The name "robber flies" reflects their notoriously aggressive predatory habits; they feed mainly or exclusively on other insects and as a rule they wait in ambush and catch their prey in flight

Leptogomphus elegans, male, Ba Vi

To my knowledge, in Vietnam, this species is only known from Mt Pia Oac (Cao Bang Prov.) and Mt Ba Vi

Male abdomen tip of 3 Leptogomphus species (from left to right) : L. perforatus, L. divaricatus, L. elegans

Gomphidia kruegeri, copula, Tây Thiên
I saw the female flying above the stream with the abdomen tip bent downward (looked so weird, I thought it was a new species for me!). Then 2-3 males rapidly appeared, loud crashing sounds ensued and the winner grabbed his girl

Burmagomphus vermicularis, male, Cuu Thac - Tu Son

Paragomphus capricornis, male, Tây Thiên

Paragomphus capricornis, male, nice facial pattern

Lamelligomphus camelus, male, obilisking in the hot sun, Cuu Thac - Tu Son

Lamelligomphus camelus, male, tip of abdomen
Two big humps (→ camel(us)...) on S8, dorsal tooth to basal part of superiors

Lamelligomphus camelus, male, Cuu Thac - Tu Son

.... doing stretching exercises

Lamelligomphus formosanus, male, Tây Thiên
For more details about this species and other Lamelligomphus (+ Ophiogomphus, Melligomphus), see great posts on Tom's blog

Lamelligomphus formosanus, male, tip of abdomen
No obvious humps on S8, no dorsal tooth to basal part of superiors, small teeth ventrally on inferiors close to bend

Heliogomphus unidentified (yet to be described ?)
Looks superficially like H. scorpio but sides of thorax yellower and caudal appendages very different. Both species share the same habitat at Tây Thiên. I also found this mysterious Heliogomphus at Ba Vi, at higher elevations (900m)

Heliogomphus scorpio (left) and Heliogomphus sp. side by side (caught at Tây Thiên along the same stream, same day). Note in scorpio the paler thoracic stripes, especially metepimeron

Ventral view of caudal appendages of males Heliogomphus scorpio (left) and Heliogomphus sp. The latter shows lateral spine of superior appendages much shorter, with 2 tooth at apex

Fukienogomphus promineus, male, Tây Thiên, + tip of abdomen (dorsal view)

Known from southeastern China and at least 2 mountain localities in Tonkin (northern Vietnam) : Mount Mau Son/Lang Son Prov. (first country record, in 2010, by Do Manh Cuong) and Tam Dao/Vinh Phuc Prov.. It was the first time I spotted this species on the lower slopes of Tam Dao, at only 350m asl.
Vietnamese specimens show reduced lateral thoracic markings along the metepisternum compare to Chinese specimens (Do Manh Cuong, 2011).

Chlorogomphus sachiyoae, male, + tip of abdomen (dorsal view)
Quite common at Tây Thiên, even along open rocky stream in degraded secondary forest

Sinorogomphus nasutus, male, + tip of abdomen (dorsal view)

Caught at Ba Vi

Chlorogomphus auratus, male, + tip of abdomen (lateral view)
Seen at Cuu Thac-Tu Son (submontane forest) and Ba Vi (montane forest). At Ba Vi, in some streams, co-occurs with Sinorogomphus nasutus

Asiagomphus sp., male, Ba Vi

Found last year at the lower slopes of Ba Vi and some specimens were collected this summer. Without any doubt this is the same unknown Asiagomphus species found in Lang Son (Huu Liên) and Yên Bai Provinces (called “species 1 or A” in Tom’s blog), on the basis of the following features : antehumeral spot (sometimes absent in some specimens), large posterior hamulus, second lateral stripe, lots of yellow on S1-2, shape of inferior appendages in ventral view.

Like “species 1”, the female is "tri-horned" : two over the lateral ocelli and one on the occipital ridge.

Same place, same species, male, but no antehumeral spot

Asiagomphus sp., male, Ba Vi, tip of abdomen
In ventral view, inferiors very widely separated in broad basin like U-shape

Asiagomphus sp., male, Ba Vi, in hand

Asiagomphus sp., female, Ba Vi, in hand
Note the strikingly broad expanse of yellow at base of abdomen

Tri-horned female : two horns over the lateral ocelli and one on the occipital ridge

According to Tom Kompier (pers. comm.), this species is probably the mysterious Asiagomphus auricolor described by Fraser in 1926 based from one single female specimen collected in "Tonkin, Ngai Tio" (i.e. northern Vietnam, exact location remain obscure - maybe Ngai Thâu in Lao Cai Prov.), and never recorded since then!

But let's wait and see Tom's conclusions on his blog.

Polycanthagyna erythromelas, female, Tây Thiên
One of the commonest jungle Aeshnids... without being a common sight – far from it

Same female, in hand. Just gorgeous...

Archineura hetaerinoides, male, Tây Thiên

Still many individuals observed mid-June, along the well-shaded stretch of the main stream around the nunnery but also downstream in much open habitat - but with dense riparian vegetation

Archineura hetaerinoides, female, Tây Thiên

Archineura hetaerinoides, male in hand
Specimens from Vietnam have larger milky white maculation on both fore and hind wings - geographical variation (Karube, 2002d)