Anax parthenope julius Brauer, 1865

The pond at Cat Ba Island where I took most of the photos below

In September 2013 I visited Cat Ba Island (southeastern edge of Ha Long Bay) and checking a wonderful pond in the National Park I observed many males Anax cruising. I first thought it was A. guttatus but their obvious smaller size cast doubts in my mind. Once in the hand it was clear that it wasn't the common guttatus but an Anax I had never seen before.
Females, unfortunately, weren't to be seen at the time of my visit.

A male, posed upon released

A male in hand

Note in the image above the reddish-brown femora, the abdomen with fawn lateral bands, the black stripe on top of frons, the unmarked bright green thorax (olivaceus-brown thorax in the nominotypical subspecies). 

Compare with the male Anax guttatus in the photo below. In general appearance, especially when seen on the wing, A. parthenope is very similar to A. guttatus. Both have a very noticeable blue saddle at S2 and S3 which really stands out in flight. Once in hand, both show green eyes and an unmarked yellow-green thorax, but there are striking differences in color pattern of abdomen, legs and frons - not to mention the structure of anal appendages.   

Anax guttatus : sides of abdomen spotted, femora almost entirely black, frons entirely green

A. parthenope julius is also smaller than A. guttatus (abdomen : 50 cm vs 60 cm in my specimens), and its flight gave me the impression to be more erratic, less powerful than that of guttatus.

Anax partenope julius, male. This really is a truly magnificent creature.

Male, facial pattern. Note the multi-colored upper surface of frons

Anax guttatus, male, facial pattern. Frons entirely yellow-green.
Male parthenope julius, anal appendages, dorsal & ventral views. Epiproct very short, very broad, toothed apically, one-fourth the length of superiors, paler than superiors, the latter with a spine at the outer side of the apex. Note also the "U" shaped marking on dorsum of S10.

Anax guttatus, anal appendages. Cerci not much different from those of parthenope but epiproct of completely different shape and proportionally longer. Dorsum of S10 unmarked.

Anax partenope julius exuviae

A. parthenope is a wide-ranging species, known from southern Europe and North Africa to the Arabian Peninsula, Siberia, India, China and Japan. In the east of its Asian range (including Vietnam, China, Taiwan, Japan, Korea, Southern Far East Russia, South Siberia) the subspecies A. parthenope julius occurs, which might prove to be a distinct species.

In Russia, the Transbaikalian records concern A. parthenope julius, the Central and West Siberian records concern the nominotypical subspecies (Kosterin, 2007).

In Vietnam, I am aware of some records in Vinh Phuc (Tam Dao) and Lang Son Provinces. Considering its distribution (Northeast Asia), it is very likely that A. parthenope julius only occurs in the northern part of the country.

To my knowledge, 4 Anax species were recognized in Vietnam*, viz. the South Asiatic A. guttatus (common),  A. parthenope julius (apparently much less common than guttatus but likely to be under recorded due to its resemblance with the latter), A. nigrofasciatus (upland species, blue saddle at S2-S3 also but body blacker than guttatus and parthenope) and A. immaculifrons (color pattern completely different than the 3 others - orange abdomen and wide stripes to the thorax). 

*update April 2016: now 5 species with the discovery of A. indicus in Hanoi (record not yet published)

Considering its range (from Japan to Indonesia), A. panybeus is also very likely to be present in Vietnam. This open-pond species is very much like A. guttatus. This is how to distinguish it based on Dr. Orr’s guidebook "Dragonflies of Peninsular Malaysia and Singapore":

1) distinct ‘T’ on the dorsal part of the frons;
2) third abdominal segment more constricted and distinctly longer;
3) male appendages differ slightly.

In conclusion, all the `A. guttatus` should be captured for in-hand examination. I know that it is a hard and time-consuming job but chasing Anax species is a perfect way to improve netting skills. It is also great fun!


Some Xuân Son goodies in the rain

Misty mountains at Xuân Son, after the rain

Back to Xuân Son National Park on July 12th. A typical rainy season day with heat, dark clouds, sun and of course (torrential) rain. At this season, depending of the day, you can have more sun and less rain, or vice versa. A completely unpredictable weather.
The morning was quite sunny but the afternoon the heavens opened and that put paid to my day. The long way back to Hanoi was an epic motorcycle journey...
Below some shots taken during this (too short) session :

Ceriagrion azureum, copula
Found at an open pond in a village. A new species for my personal records. 
In mountain areas I usually ignore open habitats in favour of forest habitats, that's why I overlooked it. 
Under these latitudes, there are often some "bad" bugs (parasitic worms/leeches) in standing water so I always avoid to submerge my butt in ponds. But this time the temptation was too strong!

Matrona taoi, male, well hidden in the forest
A newly (2011) described species, hitherto known from Xuân Son (type locality) and a site in central Vietnam (Quang Binh Province). A Matrona species with metallic green abdomen and brown-reddish wings, lacking any milky coloured reticulation at the wing bases of the male (unlike Matrona basilaris for example).

It was the only Matrona taoi I saw during this short trip. More easy to find in autumn, after the rainy season (October, November & December).

Archineura hetaerinoides, male
That smells like the end of the season for this species, more abundant in April, May and June

Chlorogomphus sachiyoae, male (identified afer in-hand examination, of course)
A typical view of a male Chlorogomphus patrolling up and down a shallow rocky stream, with a slow flight, few dozens of centimeters above water. Found this guy some kilometers before Xuân Son, in a small, incised valley (depth of 15m or so) surrounded by... manioc fields!  Other interesting species there included Coeliccia sasamotoi and Cryptophaea vietnamensis. I have already noticed that interesting forest species can still maintain in very degraded habitats if woody riparian corridors have been conserved.

Euphaea masoni, male & female

Euphaea masoni, male
Note the coppery sheen on upper-side of hind wings (not often visible, generally wings appear all dark). Its close but less common congener E. guerini show an obvious greenish sheen there (see photo below), visible even in bad light conditions; but closed winged of both species show a blue-green metallic sheen. Anyway, the easiest way to separate the two species is by taking a look at the ventral base of S9, where E. guerini has a tuft of long hairs.

Euphaea guerini, male
Note the hairs at the ventral base of S9 

Euphaea decorata, male
A widespread and common species in northern Vietnam and southern China, occurring in both lowland and mountain streams.

A newly emerged male Euphaea decorata

Euphaea ochracea, male
Seems scarce at Xuân Son - only one male spotted. 
Three other Euphaea species are found at Xuân Son (masoni, guerini and decorata), all common.

Lamelligomphus formosanus, male 
Like its congeners, this species is a hovering champion, so it should be easy - in theory - to photograph it in flight. But this little fellow is skittish and quite difficult to approach. 

Lamelligomphus formosanus, female at an oviposition spot

Prodasineura croconota, male