Wednesday, 20 November 2013

Another Ceriagrion, C. nipponicum, new for Vietnam

When at Huu Lien checking a stream we noticed a Ceriagrion with red abdomen, red face and rufous dorsum to the head and thorax sitting on some grasses growing in the stream. After a few record shots we collected it. The next day we saw several again along a different stream and also about 5 along the grassy verges of a reservoir. Apparently it was not uncommon in the area. It was easily separated from Ceriagrion auranticum, also present, by its slightly smaller size, reddish head and thorax (in fact reddish dorsum and paler ventral side). The appendages are very short. This must be Ceriagrion nipponicum, a species known from Japan and, according to Asahina, from mainland China. The present specimen has very similar appendages and mesostigmal plate to the specimen from Shanghai. I originally thought this might be C. praetermissum, but that species has longer and differently shaped appendages, different mesostigmal plate and is even smaller. This is of course a substantial range extension, but maybe it has been overlooked, as there are quite a few photos on the web of very (too?) red C. praetermissum.

Ceriagrion nipponicum, male

The same male, in hand

The very short appendages, typical of C. nipponicum

No comments:

Post a Comment