Orthetrum internum

Orthetrum internum was described by McLachlan in 1894. In Vietnam is was found by Do Manh Cuong in Vinh Phuc Province, at Tam Dao, but between 14 and 16 April we found this early flying species in Lai Chau, Lao Cai and Yen Bai Provinces as a common species. Likely it is widespread in Northern Vietnam, maybe overlooked because it flies so early. It differs from closely related O. japonicum for instance by the lack of pruinosity on the dorsum of the thorax. Here are a few photos  from Phan Xi Pang and surroundings.

The female Orthetrum internum hovering at ovipositing place over very shallow puddles

A male O. internum

The male hover-guarding the ovipositing female

Calicnemia miles

Asahina mentions Calicnemia miles from Lai Chau, a specimen collected in May 1995. Travelling along the QL 32 on April 17 in Yen Bai Province, we checked a small stream coming of the rocks and found Rhipidolestes owadai and a small red damselfly. As you may have guessed it was Calicnemia miles. Possibly it occurs more widely in Northern Vietnam. I already mentioned the species a few posts back; here are an additional shot in hand and a close-up of the appendages.

Calicnemia miles, male, a stunning little damselfly

Inferior appendages with reddish base and remainder black.

Euphaea guerini - at last

On 13 April we were birding in Xuan Son, but I also searched for dragonflies. Euphaea masoni was now very common and everywhere on the larger streams, flitting back and forth in constant arial battle, or resting on the stones. But on the small and shaded streams in the forest I also ran into them, and for some reason the ones on the larger streams seemed all dark when flying, but the ones on the small streams showed bright green flashes of their hind wings. Could it be that these were in fact E. guerini, for which I had looked in vain last year? Maybe it was a spring species? Anyway, the easiest way to separate the two species is by taking a look at the base of S9, where E. guerini has a tuft of hair. And indeed, in hand it showed this characteristic nicely. Also the differences in wing darkening (apart from the green flashes, which are more reddish in E. masoni and mind you, the closed wing of both species displays a dark blue shine) were evident, with much darker bases to the front wings and no light tips to the hind wings for E. guerini, although the latter character is somewhat variable in E. masoni and cannot in itself serve to identify. The specimens seemed to also average smaller, evident in the two in below scan, but there appeared to be some variability there too. Nevertheless, a nice addition to the list!

Picture taken in a dark place with flash, Euphaea guerini, male. The green you see is the shine of the topside op the left hind wing. 

The tuft of hair on S9. What will be its purpose, besides to aid identification?

Scan of the two species, E. guerini on top and E. masoni below. E. guerini curled up during preservation. The difference in darkening of the front wing is visible. E. masoni is 52mm in total length, HW 32mm. HW of E. guerini here is 28mm.

Bayadera strigata - another Sapa goodie*

*This entry was adjusted on December 23 after consultation with Toan, who has been working on the genus.

On the morning of April 17 we were checking some bushes near the intersection of the QL 4D and QL 32 in Lai Chau Province when Kameliya spotted a fresh damsel. Caught, it was a male Bayadera with yellow markings on the thorax and a blackish green abdomen. At home, and making use of Wilson & Yu (2007) and Davies & Yang (1996) I identified it as Bayadera bidentata. As Wilson & Yu pointed out, structurally this insect is very similar to B. strigata and they therefore suggest they may be conspecific. However, this very fresh individual has clear yellow lines on the thorax. This rules out B. bidentata, the choice being between B. hyalina and B. strigata. The small tubercle at two-fifths of the superior appendages and the yellow U-shape on the metepimeron point towards B. strigata. The penile organ also fits this species nicely. B. strigata is a new record for Vietnam and was only known from its type-locality. Additional, preferably mature, specimens are needed. Next spring!

Teneral male Bayadera strigata

Dried penile organ in close-up

Obvious ventral tooth on superior appendages in dorso-lateral view. Inferiors curled due to drying.

In dorsal view the minute tubercle on the upper inside of the superior appendage at 2/5th of its length is visible.

Sinosticta debra - another addition to the Vietnamese list

Sinosticta is a genus with 4 species. Two are blacker than yellow on the thorax, S. ogatai and S. hainanense, and to these recently two additional species have been added, both more yellow than black on the thorax and rather similar in outward appearance. These are S. debra, described by Wilson in 2007 from Guangdong, and S. sylvatica, described by Yu & Bu in 2009 from Hainan. These two species differ in minor details of the appendages, with the cerci longer than the paraproct in S. sylvatica and shorter in S. debra, in the pattern of the face, with two blue spots on the frons in S. sylvatica, and the extent of the black line along the metapleural suture, extensive in S. debra and short in S. sylvatica. None of these species have been recorded in Vietnam before.

It was thus quite a surprise to find S. debra in Xuan Son National Park on 12 and 13 April, with several males observed on both days!

Sinosticta debra, male, rather rufous individual

A different male, less reddish

Another male, this individual with somewhat restricted antehumeral stripe

Same individual with restricted antehumeral, showing blackish frons without greenish blue spots.

The appendages in lateral view. The inner tooth on the ventral side of the upper appendages not visible here, but cerci clearly shorter than paraprocts.

Likewise, cerci shorter than paraprocts, dorsal view

Sinocnemis yangbingi - 1000km from Emeishan and new for Vietnam

On April 16 we were birding on the slopes of Mount Phan Xi Pang, at about 1800m ask when I noticed a damselfly interacting in a territorial dispute with a male Mesopodagrion tibetanum. It was about the same size and likewise perched with wings held open on leaves, but instead of a whitish blue pruinose abdomen tip, it had a bright blue abdominal tip. I relocated it after a bit of searching and after a few quick record shots decided to try to catch it by hand. I luckily succeeded. But what was it? Clearly something new for Vietnam. Today while searching through the literature I came across an article by Vincent Kalkman on Mesopodagrion and Sinocnemis from 2008. It helped me to the answer: Sinocnemis yangbingi, a peculiar species known from very few locations, the closest at 1000km distance in Sichuan at Mount Emei. Quite a range extension! As this is apparently an immature male, the colors are more vivid, but the pattern is the same as in the photos in Vincent's article and both the penile organ and the appendages are identical.

Sinocnemis yangbingi, male, immature

The same immature male

Note the orange mid dorsal stripe, which will disappear when the insect matures

Typical appendages in lateral view, S8 damaged in capture

Appendages in dorsal view

Note shape of distal segment of penile organ and thick hairs along shaft.

Mesopodagrion tibetanum australe (Yu & Bu, 2009)

Between 14 and 16 April I was on a birding trip in the Sapa area (as the readers will be now know). Everyday we bumped into varying numbers of a robust damselfly in a variety of habitats, but apparently all associated with shallow, muddy and swampy places. It was certainly common. Today I found the revision of the Mesopodagrion genus by Yu & Bu and that helped clinch the ID. It is Mesopodagrion tibetanum australe, a (sub)species widely distributed in Yunnan, so it comes as no surprise that it also occurs on the Vietnamese side of the border. The photos are from specimens near Love Waterfall, but we also saw them on the flanks of Phan Xi Pang to at least 2000m asl.

Mesopodagrion tibetanum australe, male

Tandem of M. t. australe. The female has very extensive yellow on S9-10

Freshly emerged male, showing the light back of the head indicative of the (sub)species (amongst others)

Female at top, male at bottom. The male is 43mm long.