Week-end At Mâu Son & Huu Liên

Huu Liên is located 130 km from Hanoi along the National Highway 1 to Lang Son. Mâu Son lies approximately 30 kms east of Lang Son, close (c. 15km) to the Sino-Vietnamese border.
The 30th May, I did a one-day trip to Mâu Son to escape the terrible heat and in the hope of finding something new for my personal records. And on the way back to Hanoi the next morning, I made a stop over at Huu Liên. The weather was very hot reaching up to 38°C at mid-afternoon.
The highest summit of the Mâu Son mountains reaches 1500m so close to the altitude of the highest peak of Tam Dao. I arrived at 8 am. The heavy morning fog was so thick that I could barely see my own feet. I waited 2 hours for the fog to lift.

Before I visited, I asked a few fellow dragon chasers and I was recommended to follow the trail to Kuây Câp hamlet by Phan Quôc Toan and Do Mang Cuong. 
My first disappointment was the few good forest remaining. A large part of the hillsides and the top are denuded. It has reminded me of the atmosphere of the high mountain pastures of the French Alps, with herd of grazing cattle – what was missing at Mâu Son were just the soothing sound of cow bells! The old French villas have crumbled to ruins (like in Tam Dao) and the few hotels are in poor condition (big difference with Tam Dao).

By around 10.30 a.m. the sun was just poking through the heavy cloud cover. As the morning grew in light, so did the number of species. Rhipidolestes owadai, Coeliccia onoi, Cryptophaea vietnamensis, Indocnemis ambigua, Agriomorpha fusca were found abundantly, the latter with a different thoracic pattern than that I habitually encounter further south, at Tam Dao and Ba Vi.
Deception on the Gomphid front with only Leptogomphus divaricatus and Asiagomphus acco.
Other notables included Anisopleura quingyuanensis,  Idionyx carinata (7-8 females netted) and a female Planaeschna with bright yellow stripes caught at dusk, identified as Planaeschna cf. gressitti or tamdaoensis – see discussion below.
In the late afternoon, as I waded through a shallow, rocky stream, I bumped into a 3 meters high waterfall and noticed in the spray zone a quite big-sized dragonfly with bright green thoracic stripes. It was flying slowly in front of the falls, sometimes hovering. As I tried to find a safe way down to the base of the waterfall, I had already concluded that it was an Aeshnid. I approached very carefully then managed to get a few shots in flight before to net it for closer examination. Upon my return home, after a quite long and complicated diving into the literature, it has been identified as Cephalaeschna klotsi (or Periaeschna rotunda, the junior synonym). Almost all the features match perfectly with Wilson description (2008) of Periaeschna rotunda, notably the stout spine at the upper base of the male syntoracic dorsal stripe, which is a peculiar feature of this species. The BIG problem is the structure of the superior appendages which differs notably from Wilson’s and Asahina’s descriptions and drawings –  see also discussion below.
I sent my findings to Zaifu Xu, a Chinese odonatologist (many thanks to him!), and the feedback was: looks very much like Cephalaeschna klotsi (synthoracic dorsal spine, color pattern) but in all probability it is something else because of the shape of the cerci.  So it will for now be Cephalaeschna sp. - or more likely Periaeschna sp. considering the width of the frons: less than half the width of head (members of the Cephalaeschna genus all feature a relatively large frons with a width greater than half the head width).   

A quick trip to Huu Lien on the way back to Hanoi yielded another new species for my personal list... and a gorgeous one at that : Megalogomphus sommeri. An enormous Gomphid that - and this is rare enough to be worthy of note - is easily approachable. Along the same portion of stream I ran also into an old acquaintance : Labrogomphus torvus.
Of particular note was also Macromidia rapida and a Coeliccia sp. still undescribed, hitherto only known from Huu Liên and Cuc Phuong. Both were encountered along the rugged trail to Lân Ti waterfall.

All in all, despite a short list of species, it was a fruitful session at Mâu Son (the unidentified Cephalaeschna is a new species for me but also a "country first"), and a place I will return to for sure! 
At Huu Liên, it was ecstatic, as usual! 

Below some photos with discussion on the 2 Aeshnids 
Rhipidolestes owadai, male, found abundantly at Mâu Son, even in degraded forest. 
Described in 1997 based upon specimens collected at Tam Dao. Only known (scarce) from submontane and montane sites in northern Vietnam but likely to also be present in adjacent parts of southern China (Mâu Son lies only 15km from Guangxi Province).

Agriomorpha fusca,  copula

Close-up on the male. Thorax well striped.

For comparison, the kind of male we find at Ba Vi or Tam Dao (200km further south) : thorax almost entirely black. According to Wilson & Reels (2001), there are geographic variations in the synthoracic pattern of this species.

The gorgeous female Cryptophaea vietnamensis, Mâu Son

The smart male Cryptophaea vietnamensis, with a friend, Mâu Son

An interesting teneral male Cryptophaea vietnamensis, Mâu Son 
Teneral female also show blue-violet thoracic markings (see here)

ovipositing pairs of Indocnemis ambiguaMâu Son 

Indocnemis ambigua, male

Coeliccia onoi, male, Mâu Son (only known from northern Vietnam but almost certainly a junior synonym of C. cyanomelas). In his description of Coeliccia onoi, Asahina did not mention the similarity between the 2 species. It is surprising, because they resemble each other very closely (at least “superficially”, i.e. color pattern and markings). Cyanomelas is common in southern China and probably don’t stop at the Vietnamese border.  

The tricky diurnal Cephalaeschna (or Periaeschna) sp., Mâu Son, enjoying the cool misty spray of a waterfall

Measurements : abd+app 56mm, hw 46mm

Head, frontal

Facial, thoracic and abdominal patterns match very well with Cephalaeschna klotsi (or Periaeschna rotunda, the junior synonym). But the structure of the cerci does not fit descriptions & sketches of Wilson (2008) and Asahina (1982).

Tip of abdomen, dorsal, dorso-lateral and lateral views

In Cephalaeschna klotsi, superiors appendages ending, if seen from above, in a quite round head with a minute prominence at tip. But in this specimen (see photos above), superiors appendages are slender, not smoothly rounded and with pointed outer apex.

Close-up on the small spine at the outer dorsal part of the antehumeral stripe- a peculiar feature of Cephalaeschna klotsi

Wings venation

Actually I am at a little bit of a loss here. Suggestions welcome!

Planaeschna sp. cf. gressitti/tamdaoensis, female, Mâu Son
Measurements : abd+app 52mm, hw 51mm

This medium-sized Planaeschna also caused me a headache, but finally 2 species stood out from the pack: P. gressitti Karube, 2001 from southern China and Ptamdaoensis Asahina, 1996 from northern Vietnam
These 2 species are closely allied. Karube (2001) mentions some features (penile organ, cerci) to separate the males (at this time, female tamdaoensis was unknown). Later Karube (2004) redescribed the male tamdaoensis with the first description of the female, but did not mention discriminating characters separating the two females. 
P. suichangensis was also a good candidat but was ruled out on the basis of  some details in synthoracic pattern.
For now, I can only call it Planaeschna cf. gressitti/tamdaoensis*.

*update 8th June : Tom Kompier vouchered the male one week later at the same location and IDed it as P. gressitti (see his blog). This species is known from southern China (apparently only from Guangdong) and so was not unsurprising for northern Vietnam.

Facial pattern : labium ferruginous brown, labrum almost entirely yellow except black lateral margins, anteclypeus brown-yellow, postclypeus bright lemon yellow. Face of frons pitted, shiny black with sides broadly bright yellow.

Wings hyaline, tinted pale orange at the base; triangle 5-celled in fw, 4-celled in hw; anal loop 11-celled

Nine species of Planaeschna have been recorded in Vietnam viz. P. asahinai, 2011, P. bachmaensis, 2002, P. cucphuongensis, 1999, P. owadai, 2002, P. tamdaoensis, 1996, P. tomokunii, 1996, viridis, 2004,  P. guentherpetersi, 2010, P. chiengmaiensis, 1981. Only the latter is known outside of Vietnam; the others, described from specimens collected in Vietnam, have never been recorded elsewhere (and most of them are even only known from the type locality!).

Anisopleura qingyuanensis, male, Mâu Son

Anisopleura qingyuanensis, male, Mâu Son

Idionyx carinata, female, Mâu Son
Caught a lot of individuals along the trails, but all were females
Please admire the quite sophisticated stratagem so that my big fingers do not to appear on the picture!

Same as above

Head, frontal
In this species, ocellar tubercle is variable in shape, with 1 or 2 horns

Megalogomphus sommeri, male, Huu Liên. 
Steadily perched on the same stem and not at all cautious.

Megalogomphus sommeri, male, Huu Liên

Labrogomphus torvus, male, Huu Liên
Head looks very small compare to the bulky thorax

Same, from above

Asiagomphus sp., male, Huu Liên - one of the 2 unidentified Asiagomphus found at Huu Liên, both likely to be undescribed

Anax guttatus, male, Huu Liên, caught along the same portion of a slow flowing stream that the 3 Gomphids above

Coeliccia spec. nov., male, Huu Liên - new species only known from Cuc Phuong and Huu Liên (habitat : karst forest). 
Will be described soon

Same as above, dorsal view showing the 2 rounded spots on the dorsum of the synthorax

Macromidia rapida, male 

Onychothemis testacea, male, Huu Liên

Meanwhile, deforestation continues everywhere in the heart of the so-called "Nature Reserve" of Huu Liên.
Pieces of woods are carried some kilometers on foot out of the forest by dozens of transporters, men or women, young or old, 7 days per week, 365 days per year. 
SLOWLY BUT SURELY, the last remnants of good forest are being cutting down. 
Where are the rangers ?...
When will the roar of the chainsaws stop ?

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