Another Paracercion enigma from Huu Lien*

*Adjusted after publication of Paracercion ambiguum

On November 16 and 17 I observed several interesting Paracercion specimen that appeared to be different from what I had seen so far, prompting me to collect one and take shots of others. There were at least three Pseudagrion species in the area, P. pruinosum and P. rubriceps, both easy to recognize, and P. microcephalum, now also in my easy book. This however seemed to be P. spencei, but the reader will remember that this species could be recognized by the greenish lower eyes, apart from the long and bifid superior appendages. Now, the species that had me puzzled had blueish eyes. Maybe not as blue as microcephalum, but certainly not greenish. Under the microscope the similarly long, but very differently shaped appendages made it very apparent that this is not spencei. I have no idea what it is, if not that. It looks like a Pseudagrion, but strange within that group as it has two large post ocular spots, which is usual, but these are not connected by a bar in the same color. There it is, another blue Pseudagrion, very similar but different and unknown. I am open to suggestions! It is definitely a new species to Vietnam, but is it known outside Vietnam? (Now we know its true identity: Paracercion ambiguum)

Superficially similar to P. spencei, Paracercion ambiguum male

Another male, see open S2, long appendages, light blue eyes.

Two large post ocular spots, but no occipital bar

Very differently shaped appendages in dorsal view

And in lateral view, with two lobes, but no clear deep incision in superior and upward slanting inferior