185: Aciagrion occidentale Laidlaw, 1919

Number: 185 / Family: Coenagrionidae / Genus: Aciagrion   

Species: Aciagrion occidentale / Green-striped Slender Dartlet  

Habitat: Well-vegetated Ponds   

Province(s) sighted: Chaiyaphum

In flight: October / Sightings (by me): Rare

Species easily confused with: All Aciagrion species

Tiny, blue and all look the same! Talk to any dragonfly lover about Aciagrion and they instantly wince. It is an incredibly difficult and confusing genus that needs to be resolved - though anyone who dares to do it is a brave individual indeed. There are several known species in Thailand, though one or two of them could have been misidentified (possibly even by the original authors). That said, it seems that there are possibly several more out there that are yet to be described. One of which, I may have spotted last week. It is an Aciagrion species that seems to fall between A. hisopa and A. borneense with a sprinkling of A. pallidum thrown in for good measure. Superficially, it looks like A. borneense. However, the striking difference is the solid blue patch on the abdomen (save a tiny "v" nick) and the appendages are white. The colouration of the rest of the male seems to match that of A. borneense. 

Since posting this, and after a lot of hard work by a number of ode experts, it seems that there is a little light at the end of the Aciagrion tunnel of mess. Most species in Thailand, at least, can now be identified through different characteristics. And it turns out that this is, indeed Aciagrion occidentale. Commonly known as the Green-striped Slender Dartlet. I thought I had seen this on numerous occasions but no. However, this one I saw in October at Phu Khieo Wildlife Sanctuary in Chaiyaphum is correct. Yaay! I am very happy indeed. Furthermore, looking at iNat, someone has found it in Khon Kaen (where I live), so I will be looking for the female there this September onwards - it's a late season specialist.

The Male

Looks similar to all male Aciagrion species. However, the tiny 'V' nick is the giveaway, along with the white appendages. The nick or groove is variable and can be much larger.

Here is another I found, I think...

Back to Baking Heat at Phu Khieo WS

Location: Phu Khieo Wildlife Sanctuary, Chaiyaphum

Date: Thursday, 13th October, 2016

Habitat: Mid- to upland forested ponds

Well, I returned to Phu Khieo in order to find another elusive species (most of which still are and the search goes on). I knew it was Amphithemis curvistyla time. The species has apparently been recorded there and is only out for around 6 weeks and it was right slap bang in the middle of their flight time. Not surprisingly, though, I didn't get to see any. I just wonder if it is just a little too early this year due to the messed up weather and the fact that everywhere was still swamped. I will return in a week or two. Other than the usual suspects still showing in baking heat, everything is starting to quieten down now, as expected. However, even now, there was a surprise or two to be had. I managed to spot Amphiallagma parvum for the first time and they were in decent numbers, especially at the flood pond (near the marshy area where A. hisopa (or very similar) was abundant last November). The only other thing of note was a rather peculiar Aciagrion species. Could be A. borneense, but I don't think so. To add to the confusion, I saw a number of A. borneense at a slightly lower altitude (see copula below). I am at a loss as to what it is. I saw 3-4 males the one natural, uplands pond (where I once stood on a massive python, which didn't even react). Sadly, I had forgotten my net and was unable to capture any. I will return very soon and try again. 

My best photos of the day:

The conundrum of the day: Aciagrion.... what?

Aciagrion borneense, copula (at slightly lower altitude). Here you can just make out the wide black markings on the abdomen - which makes it easier to separate, whereas the specimen above is almost solid blue.

Welcome to Phu Khieo... my first sighting of the tiny, but stunning Amphiallagma parvum, male...

 ... and the female

The usual equally beautiful Ceriagrion azureum (though in much smaller numbers now)

Aciagrion pallidum, male - with white appendages (some have an orangy colour).

Orthetrum pruinosum neglectum, male. Very common right now.

 Diplacodes nebulosa, copula. These were everywhere - but my first decent shot of a copula.

The super-common Ischnura senegalensis, copula. Still nice, though

 Lestes concinnus, replaced most of the other Lestes species now and was incredibly abundant.

Gynacantha subinterrupta, teneral male - usually abundant everywhere, but rather scarce here.

Ischnura aurora aurora, male - a few made an appearance

Lestes elatus, female. Seemingly more abundant later in the year.

Very scarce here, for some reason... Orthetrum luzonicum, teneral female

Ooops ... poor damsels.

Can you guess the species?

 Orolestes octomaculata, teneral female

... and this one?

 Cratilla lineata calverti, teneral male

What, no frog?!?
Not all dragons fly. This stunning, but lazy Monitor Lizard was plonked right in the middle of the road.

 No idea what species, but there were several along the road early in the morning. This one was a decent size.