Caliphaea thailandica Asahina, 1976

A rare and elusive Caloptera damselfly, inhabitant of shadowy streams in forested mountain slopes. Only males were observed.  

Caliphaea males can not be confidently identified without capture and close examination of the caudal appendages. Females are either hard or impossible to identify.

Synthorax metallic green with coppery reflections on dorsum and on sides. Metepimeron yellow with large metallic patch in the centre. 

Abdomen coppery metallic. In mature insects, the terminal three segments are covered with pruinescence.

Caudal appendages : 

Lateral view

The superiors are roughly of the same structure with those of the 4 other known Caliphaea species (angka, confusa, consimilis, nitens). Best key features are the inferior appendages that differs strikingly from those of the 4 congeneric species : quite straight in profile view, very simple, not broadened and without interior processes at the extremity.

  Dorsal view

C. thailandica is a poorly known and scarce species, recorded from a few locations in Thailand and only one in Vietnam (Mount Tam Dao).

At Tam Dao, I found this species along two narrow, shallow, rocky streamlets with dappled to dense shade, in undisturbed forest, at the altitude of ca 750m and 900m a.s.l., 5 km away from each other. Most of the specimens have been spotted perching on sunny spots on the leaves of overhanging vegetation.

The list of known Caliphaea species is as follows:

• C. confusa Hagen in Selys, 1859 (known from northeastern India, Nepal, Myanmar, Bhutan, southwestern China, northern Vietnam)

• C. consimilis McLachlan, 1894 (China : Sichuan, Yunnan, Guangdong, Guangxi) 

• C. nitens Navas, 1934 (China : Zhejiang, Fujian and Guangxi)
  

• C. thailandica Asahina, 1976 (Thailand, northern Vietnam) 

• C. angka Hamalainen, 2003 (northwestern Thailand : Doi Inthanon)

Ventral view of the caudal appendages of 5 Caliphaea species.

(Sketches of angka, confusa, consimilis and nitens from photos of Matti Hämäläinen).

From the structure of inferior appendages (in red) it is not difficult to

separate C. thailandica males from the other congeneric species.

Many thanks to Noppadon Makbun and Matti Hämäläinen for providing documents!