Saturday, July 30, 2011

000. Onychargia atrocyana (white pruinosed form)

Number: 000
Family: Coenagrionidae
Genus:  Onychargia
Species:  Onychargia atrocyana (white pruinosed form
(Common name(s): Marsh Dancer, Shorttail, Black Marsh Dart
Thai name(s): แมลงปอเข็มพุ่มผู้ดำ
Habitat: Small natural uplands farmer's pond
Province(s) sighted: Nam Nao environs (Petchabun).
Sightings (by me): Rare
In flight (that I have seen): July (though must be longer)

In bamboo shelter (from the rain) at a farmer's pond 2 kms south of Nam Nao town, I saw a damselfly that easily won strangest specimen of the day award. It is clearly male, Onychargia atrocyana (see entry). However, I have seen hundreds and hundreds of this species and I have never seen one that has white pruinescence. 

Noppadon Makbun took a look at the photos and he said that he has only seen the pruinosed form in China. I think it looks great and I am going to return to the same place on Saturday to see if I can find the female and see if it, too, takes on this form. Ironically, its common name is Black Marsh Dart... maybe it should be White Marsh Dart. 

And though it's not a separate species from Onychargia atrocyana, I believe it deserves its own blog page.

This has now been revised and has a more recent page as it has in fact been separated.


  1. I agree with all your guess. I only see this pruinosed form of Onychargia atrocyana in China. I'm so glad that this form is also found in Thailand.

  2. Yes,It is Tetracanthagyna waterhousei.

  3. Thanks Noppadon & Mapor. I have moved the photos of the other 2 species to their own page.