Sunday, December 19, 2010

10. Urothemis signata signata (Rambur, 1842)

Number: 10
Family: Libellulidae
Genus: Urothemis
Species: Urothemis signata signata 
Common name(s): Scarlet Basker, Greater Crimson Skimmer
Habitat: Exposed lowland areas 
Province(s) sighted: River Chi, Nam Pong NP (Khon Kaen); Khao Yai NP (Nakhorn Ratchasima); Nam Nao environs (Petchabun)
Sightings (by me): Common and widespread
In flight (that I know of): April-November
Species easily confused with: Crocothemis serviliaMacrodiplax coraRhodothemis rufa

Another common dragonfly that loves sunbathing is Urothemis signata signata. It loves perching on sticks and branches in the blazing sunshine. They can be easily confused with Macrodiplax cora (Noppadon Makbun corrected my initial I.D.), but the main difference is that only the latter segments of the abdomen have black dorsal marks, whereas M. cora has black marks all along the abdomen. Also, I think M. cora is only found as north as Bangkok (this bit is not true anymore ... I found M. cora in Khon Kaen.)

The mature male (red form)
Has long legs like Trithemis species.

Here, you can clearly see only the last 2 segments have black dorsal patches, which helps identify the species.

The young male? (yellow form)
I am convinced that there are two forms of this species. Though the red form is far more common, and all start off life yellow (and become red) I have spotted some rather old-looking yellow males and females. Maybe some just don't become red. No idea why.

... a strange male
Here's a male from Chantaburi that has a red face and dark red eyes (the ones in KK have a whitish face) and also it has no distinguishable marks on the abdomen. I saw several like this but were very difficult to get near. 

The adult female (red form)
The female is very similar to the male. They are less easily frightened than the males and seem to like having their photo taken!

Slightly younger female (has a beautiful marbled effect)

Target sighted ... she's about to strike

Young female (yellow form)

Female in the hand ...
Unfortunately, this 'yellow' female I found dead in a spider's web (freshly killed). 

... a very old female (that is still yellowish)

I have seen this species in vast, open spaces and farmer's fields to small swampy enclosed areas (but still in the bright sunshine),   and I have spotted them at many locations around the country.  Also, if you spot one, you will probably see lots at the same time.

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