Wednesday, 31 December 2014

Neurothemis species at Cat Tien

In the north of Vietnam I bump into Neurothemis fulvia regularly. At Ba Be for instance it is really common. The other Neurothemis here is N. tullia, but I have here in the north only seen it at Van Long. Plus a lonely record of N. intermedia at Cuc Phuong of a single female. But at Cat Tien there are three common species. N. fulvia occurs all over the place. N. tullia is common especially at the fishponds. And Neurothemis fluctuans is a small red-winged species that I have not seen in the north, indeed I am not aware of any records in the north. During my visit in November I also saw a single female (again) of N. intermedia. Although apparently in Thailand for instance this can be a very common species, here I saw just a single specimen at a dried out former pond in open terrain. Maybe she had just sort of happened upon the place, a drifter. Below some shots of the Neurothemis species I took during the trip and a few shots of Brachythemis contaminata. That very common species is a possible pit-fall for female and immature N. fluctuans.

Let's begin with the male of Mrachythemis contaminata. The black middle line on the abdomen and the orange wing-pattern, darker near the middle, help identify. 
This is the female of B. contaminata. The blackish line along the dorsum of the abdomen is very obvious and absent in the Neurothemis species.
Female Neurothemis fluctuans. Note the dotted line close to the lateral carina and only a very thin line over the dorsal carina on the abdomen.

In dorsal view, the dotted line located just short of at the very edge of each segment.

Another female showing the typical dotted line on the abdomen. This specimen also with darkened wingtips.
The immature male showing the same, but somewhat more pronounced abdominal pattern and the wing pattern of the adult male in orange brown.
The mature male, with abdominal pattern obscured by dark reddish colour and now deep red wings, with the transparent tips to the hind wings extending along the posterior edge towards the middle.

In comparison, male N. fulvia, with transparent tips reduced to the apex of the wing only, not extending along the posterior edge.

Another male N. fulvia. The transparent apex starts halfway the pterostigma.

Female N. intermedia, with typical broad uninterrupted lateral line and dark humeral stripe

Female N. tullia, smallish species with dark brown and white wing pattern.

The male of which has extensive black on inner wings and whitish-grey outer wings.

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