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).