Noguchiphaea yoshikoae Asahina 1976

My first ever contact with this species, at Ba Vi.  Two females sitting high up in a tree, shot with the 500mm lens I usually use for birds. Not the best photo in the world, but a memorable encounter.

 
Noguchiphaea yoshikoae is a small to medium sized Calopterygid. This is a rather weak flier, usually perched inconspicuously on trees and bushes along the streams.

Short description:

Prothorax with horns on middle of posterior margin. Synthorax shining greenish, excepting the lower part (metepimeron) and ventral side entirely yellow. 
Wings hyaline, only the extreme apex of forewing spotted (in mature males).  
Abdomen slender, entirely metallic greenish. The dorsal side of S8-10 are pruinosed in adult male. 

Sub-adult male : greyish - not whitish - dorsal patch on S8-10 and forewing tip without dark marking in the middle. Picture taken at Tam Dao at the beginning of the flying season (mid-August).

Mature male with dark marking at apex of forewings.

Caudal appendages black. Superiors quite unique, with apices  broad and thin, and abruptly cut squarely. There is a sharp spine at the middle of superior append and another small one between the median spine and apex. The inferiors are quite short and inconspicuous, slightly pointed.

 Dorsal view

 Lateral view.

 Dorso-lateral view.

 Teneral male with wings still crumpled, found sitting on a leaf in the middle of a stream. 

The female is almost identical to the male, but slightly more robust.

The horns on the posterior lobe of the prothorax are also more apparent. I hope to add good pictures of this one next year!

In northern Vietnam, N. yoshikoae can be easily confused with Vestalaria miao and V. smaragdina (two other rare Caloptera species). Despite the fact they belong to 2 different genera, they are look very similar in size, overall shape and color pattern. But there are clear structural differences in the shape of the caudal appendages and the posterior lobe of the prothorax (no horns in V. miao and V. smaragdina ). 
In Xuan Son National Park, they can be seen along the same streams.

Noguchiphaea yoshikoae was considered as a Thai endemic until its discovery in Vietnam in 2007 by Dô Manh Cuong, at Tam Dao, at the altitude of 700m.

Some years after, this species has also been discovered at Xuân Son National Park, located 100 km north-west from Hanoi, at an elevation of only 450m - a record for this species.

And at the end of september 2011, I bumped into 2 males and 2 females in Ba Vi National Park (40 km south-west from Tam Dao), along two streams, at ca. 600m. This new record was confirmed by Dô Manh Cuong. So, actually, in Vietnam, N. yoshikoae is only known from tree sites, all in the North.

Remarks: In 2006, a new species of Noguchiphaea has been discovered in Khanh Hoa Province (southern Vietnam), named N. mattii. Except for the difference in known distribution – N. yoshikoae being found both from northern Thailand and northern Vietnam, whereas N. mattii is so far recorded only from southern Vietnam – the two species live in very similar habitats.

The male of N. mattii differs from N. yoshikoae in several major characters, notably color of metepimeron, structure of prothorax,  superior anal appendages, penile organ.

Tam Dao is an island of biodiversity completely surrounded by agricultural plains with a high population density. This isolated mountain ridge, that rises from the surrounding agricultural lowlands, runs 80 km from north-west to south-east. It has more than 20 peaks with the elevation over 1,000m, several surpass 1,300m and the highest, Mount Tam Dao Bac, is 1,592m. It is a "hot-spot" of biodiversity (for insects, but also for reptiles, amphibians, birds and plants).