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

Rhinagrion hainanense Wilson & Reels, 2001

Male, Xuân Son National Park

Wilson and Reels (2001) described Rhinagrion hainanense from a single male collected from Lumu, Hainan, in June 1999. Rhinagrion yokoii Sasamoto, 2003 is a junior synonym of this species (Kalkman and Villanueva, 2011).

All the photos of this post were taken mid-October 2013 at Xuân Son National Park (Phu Tho Prov., northern Vietnam).

The males of the genus Rhinagrion are among the most striking and colourful damselflies. In the field they are easily recognized by having a colourful abdomen with red, blue, orange or pink markings and wings that are hyaline and open at rest.

They perch quite low above the ground and make short flights on the edge of, or within, dense shrubby vegetation along streams.

 Male

Some features of the male Rhinagrion hainanense  : 

Head black with extensive blue-green pattern.
Antehumeral stripe roughly parallel sided, covering about two-thirds length of synthorax. 

Side of synthorax with dark stripe along metapleural suture not connected to dark dorsum of synthorax. 

Male in hand, for better view

Male, facial pattern

Abdomen largely brown-reddish, S3–7 with pale band on posterior half of each segment, S8–10 black with pairs of blue dots on S9–10, superior appendages pale. Sternum of S7–10 brick-red.

Male, tip of abdomen, lateral and dorsal views

During the courtship, this male was hovering in front of the female and arched his abdomen to display the bright brick-red color on ventrum of S7-10 (abdomen was bent downwards at right angles so more bent than the left shot show). The crappy photo in the right show quite well how the tip of abdomen was spread out. And it was not only spread out, it also quivered like a tiny flag!

Female is much less colorful than the male. She show a pale version of the male color pattern, with an apricot ground color. Antehumeral stripe blue-green.

Female

Same, close-up

A male and 2 females at an oviposition spot (muddy banks of a pond)

Ovipositing female 

In his blog thaiodonata, Dennis Farrell photographed a female ovipositing at the base of a log overhanging a stream (see here)

Rhinagrion hainanense is currently known from China (Hainan, Guizhou Prov.), Thailand, Laos (as R. yokoii from Sekong in southeastern Laos), northern and central Vietnam [Xuân Son National Park (Phu Tho Prov.), Cuc Phuong NP (Ninh Binh Prov.), Chu Yang Sin NP (Dak Lak Prov.), Phong Nha-Ke Bang NP (Quang Binh Prov.), Phong Dien Nature Reserve (Thua Thien Huê Prov.), Khanh Hoa Prov.].
The locality at Chu Yang Sin National Park in Vietnam was given as a “sandy forest stream” and that at Phong Dien Nature Reserve as “2m wide and 20 cm deep through disturbed forest”. In Hainan the species is found in dense vegetation beside shady, slow-flowing streams in lowland areas (Kalkman and Villanueva, 2011).
The locality at  Xuân Son National Park - where these photos were taken - is a 30m x 5m pond with clean water, 1 m deep, at the edge of an undisturbed lowland forest.

In August 2013, I also bumped into a male at Tây Thiên (lower slopes of Tam Dao NP), at a tiny pond in degraded secondary forest.

Ten species of Rhinagrion are known. Four are known from continental southeast Asia (hainanense, mima, viridatum, macrocephalum) and the remaining six species from Indonesia, Philippines and North Borneo (Sabah) :

-Rhinagrion borneense Selys, 1886 Brunei, Malaysia (Sarawak, Sabah), Indonesia (Kalimantan)
-Rhinagrion elopurae McLachlan in Selys, 1886 Malaysia (Sabah)
-Rhinagrion hainanense Wilson & Reels, 2001 [syn: Rhinagrion yokoii Sasamoto, 2003] China (Guizhou, Hainan), Laos, Vietnam, Thailand
-Rhinagrion macrocephalum Selys, 1862 Peninsular Malaysia, Indonesia (Sumatra)
-Rhinagrion mima Karsch, 1891 Burma, Indonesia (Sumatra), Thailand, Vietnam
-Rhinagrion reinhardi Kalkman and Villanueva, 2011 Philippines
-Rhinagrion philippinum Selys, 1882 Philippines
-Rhinagrion schneideri Kalkman and Villanueva, 2011 Philippines
-Rhinagrion tricolor Krüger, 1898 Indonesia (Java)
-Rhinagrion viridatum Fraser, 1938 [removed from synonymy of R. mima] Burma, Peninsular Malaysia, Thailand 

Note that R. mima has also been recorded in Vietnam, at Phu Quoc Island (extreme south-west of the country).