Thursday, 7 August 2014

Lyriothemis elegantissima - a beautiful dragonfly new for Vietnam

Lyriothemis is a genus of beautiful flat-bellied dragonflies with 15 species, represented in Vietnam by only one species, the distinctive L. bivittata, a bit a stranger in the group by its strictly arboreal habitat, whereas many species inhabit marshland. Anyway, that was the status quo until this spring Sebastien found L. tricolor (L. flava) in Xuan Son. And now a third species has been identified, beautiful L. elegantissima. It occurs in Cat Tien National Park in grassy inundated clearings in forested surroundings, where I saw at least 6 males and females in active display. Sadly my cameras were both wet and my lenses fogged up, so I could not take proper pictures in the field. Asia-dragonfly also mentions VN for L. cleis, but I have found no substantiation for this, although it is of course possible. This species looks superficially like L. elegantissima, with somewhat similar thorax pattern. The abdomen is differently patterned and the hamule differently shaped. James Holden had already found this species during the weeks preceding my visit to Cat Tien and I only relocated it on the last day of my visit, but it was worth the search! Males and females would perch in pairs or would dance around each other in the air in hover flight.
Its occurrence in Vietnam is not totally unexpected. It is distributed from the Japanese islands close to Taiwan, like Ishigakijima, from Taiwan itself and mainland China provinces like Guangdong and Guangxi, but also from Thailand. The latter fact suggested it might also occur in Laos and Vietnam. And indeed!

Lyriothemis elegantissima, male (right) and female (left)

Lyriothemis elegantissima, male

Even foggier, Lyriothemis elegantissima, female

Scan of dorsal side of male (top) and female (bottom). Note the differences in color of pterostigmata.
Detail of hamulus

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