Wednesday, 29 October 2014

A fourth Planaeschna species from Xuan Son

Sunday October 26 was highly productive for Planaeschnids, with 4 species observed at Xuan Son National Park. This is rather exceptional for me, but I love them. Haomiao Zhang in personal comments stated that this highly speciose genus has at least 50 species with many in southern China. It comes as no surprise that the same goes for northern Vietnam. Indeed, we are only starting to scratch the surface. Partly this is because visiting scholars have been focussing on spring and early summer, whereas many Aeshnids fly in autumn.

After I caught the first "not gressitti" (see earlier posts) I saw another patrolling a square meter of open water on a stream inside the forest. I was able to catch it and although it looked similar, it also clearly was much larger. In fact the "non-gressitti" was 65mm total body length, but this specimen was 75mm. Of course, in detail it is also rather different. For now I need to treat it as yet another species incertae.

Planaeschna species novum / species incertae, male. Note the straight appendages (see below)
The four males caught. Left P. guentherpetersi, middle row P. "not gressitti" and right the present larger species. Note also the variation in the pattern of S2, with 6 marks in the larger species, 5 in P. guentherpetersi and 4 in "not gressitti"

Appendages in dorsal view, robust, straight

But also suddenly expanded in dorso-lateral view

Robust and straight in lateral view

Penile distal segment in ventral view, Angular in outline and with moderate earlobes
In lateral view, earlobes visible

Facial pattern in brown, not black

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