126. Brachydiplax sobrina (Rambur, 1842)

Number: 126

Family: Libellulidae

Genus:  Brachydiplax

Species:  Brachydiplax sobrina

Common name(s): Little Blue Marsh Hawk

Synonyms: Brachydiplax gestroi (Selys, 1891); Brachydiplax indica (Kirby, 1889) *

Habitat: Large, exposed rivers, small lowland forested ponds

Province(s) sighted: Large river, Lomsak environs (Lomsak); River Chi, Khon Kaen environs; small lowland forested ponds (Udon Thani province)

Sightings (by me): Rare (though common in one area of Udon Thani province)

In flight (that I have seen): July-October

Species easily confused with: Brachydiplax farinosa; Brachydiplax chalybea; Aethriamanta gracilis

A really difficult genus to ID is Brachydiplax. However, with the help of Noppadon Makbun and Oleg Kosterin, I am now able to ID species in the field (hopefully). With Brachydiplax sobrina I am leaning towards their preferred habitat being large exposed rivers, as opposed to marshy/weedy ponds preferred by other species in the genus - though I could be completely wrong, especially as its common name is Little Blue Marsh Hawk.

(Yes, I am wrong ... I have seen this species thriving at small farmer's ponds.)

The male

The male is almost identical to other species in the genus. However, it can be identified by its antenodal crossveins. This species has 7 as opposed to 8-9 of B. farinosa. I first saw this species back in 2008, I saw it again briefly in 2011 and then recently in Udon Thani province where it seemed fairly abundant, though mature males were hard to approach.

An unfortunate ending ...

The young male

Similar to the older male, but the thoracic markings are still visible.

The best way to separate this species ... 

I haven't managed to spot the female, though it was photographed recently at the same place in Udon Thani, by my fellow Issarn dragon hunter, Joe Hartman. I will return to find her one day soon.

* [source: http://www.iucnredlist.org]

46. Brachydiplax chalybea chalybea (Brauer, 1868)

Number: 46

Family: Libellulidae

Genus: Brachydiplax

Species: Brachydiplax chalybea chalybea

Common name(s): Greater Grey Skimmer, Yellow Patch Lieutenant, 

Blue Dasher, Rufous-backed Marsh Hawk 

Thai name(s): แมลงปอบ้านสีตะกั่วทุ่งนา

Habitat: Exposed ditches, drains, ponds and lakes (uplands & lowlands)
Province(s) sighted: Widespread (Khon Kaen); Nam Nao NP/environs (Petchabun);  Phu Rua environs (Loei); Widespread (Chiang Mai); Khao Yai (Nakhorn Ratchasima); Khao Soi Dao (Chantaburi); Kabin Buri; large lagoon (Prachaub Khiri Khan); Undon Thani
Sightings (by me): Extremely common
In flight: March-December (probably all year)

Another handsome dragonfly that is part of the Brachydiplax genus is the common Brachydiplax chalybea chalybea. This species is widespread and can be seen at most ponds, pools and lakes that have tall reeds at the edge. They are also very small in terms of dragonflies, but the colours are amazing.

The male

The male has a striking blue and orange thorax, backed by a blue abdomen with black segments towards the end. It is a truly magnificent dragonfly and one you can see almost anywhere in the lowlands and many upland places too. Be aware though, as they are easily frightened and fly away at the slightest thing. This one is obelisking (doing a kind of handstand), in order to minimize the amount of sun on its body. 

The young male ...

Not commonly seen at this stage.  He is very orange indeed!

The female

Oddly enough, even though the male is very common, the female is not so. Or, at least, it is seldom seen. I have spotted the female only on a few occasions, often hiding away in the trees and away from the frisky males and only come down to the water's edge briefly. As far as I am aware, they stay well away from the water and only become visible when they are ready to copulate.

45. Brachydiplax farinosa (Krüger, 1902)

Number: 45
Family: Libellulidae
Genus:  Brachydiplax

Species:  Brachydiplax farinosa

Common name(s): Black-tailed Dasher

Synonyms: N/A

Habitat: Exposed ponds and marshes

Province(s) sighted: Nam Nao National Park and environs (Petchabun); Phu Wiang National Park (Khon Kaen environs); (widespread) Chiang Mai environs; Chiang Rai; Udon Thani province

Sightings (by me): Common

In flight (that I have seen): Year-round

Species easily confused with: Brachydiplax sobrina; Brachydiplax chalybea; Aethriamanta gracilis

Brachydiplax is a beautiful, but difficult to positively ID species. Most of them look the same and worse still, some species in the genus Aethriamanta can also look very similar. Of the Brachydiplax genus, B. c. chalybea is the most common and I find it easy to ID with its orange and blue-coloured thorax. Brachydiplax farinosa is the second most common species and can be found at many ponds/marshland which have lots weedy edges. B. sobrina is rather rare (I have only spotted it 3-4 times) and seems to prefer large, exposed rivers (not true anymore!).

The male
The male is small but beautiful with its bright blue thorax and blue/black abdomen. They are commonly seen at exposed and weedy ponds and marshes, often 'doing battle' with other common species. 

 The young male ...

yet to sport his classic powery-blue coat.

Male in the hand ...

How to ID this species ...

Identifying this genus and other similar genus is extremely difficult. Thanks to Noppadon Makbun and Oleg Kosterin's invaluable information, it is possible to do so in the field. The male has 8-9 antenodal corssveins, whereas other species have less. 

The female

Like the male, the female is difficult to differentiate from other females in the genus. Fortunately, they are often spotted close to where the males are situated.

Very old female ...

Here's a very old female from Nam Nao National Park, Petchabun.

A very young female ...

This female I saw at Nam Nao National Park, Petchabun

A teneral female ...

This specimen has 9 antenodal crossveins