Periaeschna furukawai - a new Periaeschna species described

*Original posting updated on December 6, 2022. This species was described in Karube & Kompier, 2018

The Yen Bai area is a true treasure trove for Aeshnids in early summer. Several species of Planaeschna, of Periaeschna, of Petaliaeschna, of Cephalaeschna. Haruki Karube had alerted me to the occurrence of a large Periaeschna of which he had only seen teneral specimens. Well, June 30 was a very hot day and around midday quite a few Aeshnids were hanging in cool shaded places along one of my favorite streams. One specimen was flying around a bit between a few large boulders and I was able to catch it. It appeared to be a Periaeschna, but it just seemed very bulky. Later at home the difference between this specimen and normal P. magdalena was striking. Even if I have not been able to catch a male yet, this must be the enigma large Periaeschna sp.  and a possible species novum. At 76mm this is a large insect! (Together with Haruki Karube I described this species in 2018, after I had also collected a male in 2016 as P. furukawai.)

This insect is almost identical to P. magdalena, but it is much larger 

And, as is visible here in lateral view, the yellow markings on the abdomen are much more prominent

The real Periaeschna magdalena?

A month ago in Yen Bai I caught a male Periaeschna sp. that at the time I thought solved a problem I ran into a week earlier. At that time I had seen a male Periaeschna hanging in a bush, but failed to catch it. The weekend after I caught a Periaeschna in the same general area and sort of wanted to associate it with the earlier male. Nevertheless the color of the eyes seemed different, the leg color was not blackish and the color of thorax and stripes seemed brown and yellow-green, not blackish brown and green. Recently I bumped into other Periaeschnids, in Ba Vi and in Xuan Son, both a female and several males. These convinced me that the Yen Bai Periaeschnids, apart from the one hanging in the bush, were something else. I have adjusted that entry into Periaeschna sp. But what is then Periaeschna magdalena? Taiwanese P. magdalena seem not as green, more yellow, as their thoracic stripes are concerned, and their eyes are not blueish, but yellow-green. Now, this may be geographic differences, and for the moment I will consider them as such, but I have a gnawing suspicion that there is more even than meets the eye and that these may be separate species. Maybe the answer lies in P. nocturnalis. This species could well be it, but the color of the eyes is not mentioned in Asahina (1986). There is unclarity relating to the occurrence of nocturnalis/magdalena in Vietnam. Karube (2004) regards the Vietnamese material as P. magdalena.

I have not been able to find a drawing of the penis, but I did take a picture. Maybe someone has material to compare it with?

Periaeschna magdalena, female, Ba Vi, May 25

Close-up of wing-base

Male Periaeschna magdalena, Xuan Son, June 8

Another male from Xuan Son, June 1

Appendages in ventral view of June 8 male

Apical segment of penis

Lateral view of same individual

The appendages in dorsal view of the June 1 male, distorted on one side

Scan of female from Ba Vi

Scan of Xuan Son male of June 1

Xuan Son male of June 8

Periaeschna nocturnalis - not magdalena afterall

*After communication with Wen Chi-Yeh, I went back to the description and drawings in Asahina of P. nocturnalis. There are several indications that point to that species. No clear basal patches in the wings, the straight line on the metepimeron, the reddish brown legs, the shape of the cerci and the abdominal pattern. For now I will consider these individuals as this taxon (updated June 16, 2014).

Two weeks ago I failed to catch a Periaeschna species in Yen Bai Province, although I did take some pictures and from that it appears to be P. magdalena. See the concerned entry. Luckily, when working the streams around Nam Bung on May 11, I bumped into several Aeshnids and was able to catch one and take pictures of a female. In hand there seemed little doubt that at these were P. magdalena, although they appear more yellow and less green than the specimen a week earlier and had differently colored eyes. However, by now (mid-June) I have caught several other P. magdalena, in Ba Vi and Xuan Son. They invariably display all dark legs, dark blue eyes, much darker thorax pattern contrasting with the light stripes, differently shaped antehumerals and differently shaped appendages. In fact, they are very different insects. I handed over my male specimen of this species to Karube, so I cannot check it now, but this must be a different Periaeschna species.

Male Periaeschna sp., a quite beautiful Aeshnid

Thorax and head in close-up

The female hanging in a bush at a safe distance

The appendages, close to Asahina (1981), but in fact slightly different

And likewise, in lateral view

Periaeschna magdalena - until proven otherwise

When checking a small stream just west of Nam Bung in Yen Bai Province on April 30, Kameliya spotted an Aeschnid hanging in a bush by the stream. I was able to take a few record shots, but failed miserably in catching it, as it was hanging smack in the middle of a thorn bush. There was a lot of cursing going on, but today I studied the venation of the wings and was able to pin down the genus as Periaeschna. Only one species is known from Vietnam, but 5 occur in China, so it is quite likely that other species will also occur in Vietnam, besides the known P. magdalena. The pattern of the abdomen, the all dark legs, the brownish frons, the small brown basal spots to all wings however all fit P. magdalena nicely. Asahina (1981) produced descriptions of the species that proved helpful and newly described species from Southern China (by Wilson and by Xu) do not fit. But I am open to suggestions.

Male Periaeschna magdalena with its very dense wing venation typical of the genus (median space with many crossveins)