125: Brachydiplax sobrina (Rambur, 1842)

Number: 125 / Family: Libellulidae / Genus: Brachydiplax

Species:  Brachydiplax sobrina / Little Blue Marsh Hawk

Habitat: Large, Exposed Rivers, Small Lowland Forested Ponds

Province(s) sighted: Lomsak), Khon Kaen, Udon Thani 

In flight: July-October / Sightings (by me): Uncommon

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 the 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.

The Young Male

Similar to the above but devoid of pruinescence. That will come later.

An unfortunate ending ...

The best way to separate this species ... 

The Female

Compared to the male, the female is very rare. In fact, since I saw my first ever male in 2008, I have only seen two females and one of them almost escaped my lens... well, it may have well as done as the shot was so poor. Roll onto 2021 at the River Chi in Khon Kaen with Andrew Pierce while looking for a very rare butterfly I had once seen there and boom... there was a female! As clear as day and got loads of great shots. It was like finding a new species... no, better! And here she is:

46. Brachydiplax chalybea chalybea (Brauer, 1868)

No: 46 / Family: Libellulidae / Genus: Brachydiplax

Name: Brachydiplax c. chalybea / Rufous-backed Marsh Hawk 

Habitat: Ponds and marshes, uplands and lowlands
Province(s): Widespread
In flight: Year-round / Sightings (by me): Very common

Easily confused with: Aethriamanta gracilis, Brachydiplax farinosa, Brachydiplax sobrina  

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)

No: 45 / Family: Libellulidae / Genus: Brachydiplax

Name: Brachydiplax farinosa / Emerald-flanked Marsh Hawk / แมลงปอบ้านสีตะกั่วขนขาว

Habitat: Forested ponds and marshes
Province(s): Widespread
In flight: Year-round / Sightings (by me): Common

Easily confused with: Aethriamanta gracilis, Brachydiplax chalybea, Brachydiplax sobrina  

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.

The 'Teneral' Male

This is a newly emerged male. Probably a few hours old, but very dark.

And another with 7 antenodal crossveins on the left side and 8 antenodal crossveins on the right...

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 crossveins, 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. It is generally orangey coloured dorsally along the abdomen with black stripes.

Very old female ...

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

The 'Very Young' Female ...

This female I saw at Nam Nao National Park, Petchabun.

The 'Teneral' Females

Three teneral females and all look somewhat different. Am I missing something?