Monday, 21 October 2013

Ceriagrion fallax and Ceriagrion bellona*

*This entry was adjusted on 22 November 2014, after I encountered the real C. chaoi in Cat Tien National Park.

When checking a small very clear manmade pond at Xuan Son National Park first a large yellow Ceriagrion flew into my vision. Reminiscent of C. melanurum that I know from Japan, it is a bit like a small flame moving about. Voracious as I remember C. melanurum too. A large splendid Ceriagrion, not uncommon, apparently, but I had not seen it before. Then when scanning some of the floating water plants I also noticed a smaller reddish Ceriagrion. Unlike C. auranticum the thorax was not greenish, and it looked a bit like C. malaisei. However, clearly it had darker dorsal S8-10, something not apparent in that species. There were quite a few about, in copula ovipositing. Nevertheless, it was not easy to catch one and one I did I let it escape again. But eventually I could make some close-ups and confirm it was Ceriagrion bellona. (*Originally I had identified this species as C. chaoi, which has very similar appendages, another species not known from Vietnam. After encountering an intriguing species in Cat Tien in autumn 2014 that eventually I identified as C. chaoi it became clear this was in fact C. bellona, see also the entry on C. chaoi.) I know of no records from Vietnam before. It is smaller than the rather similar C. malaisei, with very different appendages, a darker dorsal side of the synthorax and rather apparent darker dorsum to S8-10. For reference I include below the appendages of C. malaisei.

Ceriagrion fallax, male

A large species, bright yellow, with blackish dorsum to S7-10

Three copula of Ceriagrion bellona

Ceriagrion bellona, male, with characteristic darker S8-10

Appendages of C. bellona, male

And for comparison, the very differently shaped appendages of C. malaisei

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