Sunday, 24 January 2016

My third Vestalaria species in Vietnam: V. vinnula

In September last year I visited the mountains west of Da Nang close to the Laotian border and one of the objectives was Vestalaria vinnula, which had been recorded there by Toan previously. Interestingly on the stream where it was supposed to occur I found the very similarly looking V. miao. This is not to say that V. vinnula there had been a misidentification. I have seen the specimens and the identity is beyond doubt. Apparently in a different season a different Vestalaria inhabits the same stream. Very interesting. But I was of course also disappointed.

But when in December we visited Lam Dong Province near Da Lat one of the few damselfly species around was in fact Vestalaria vinnula (co-occurring there with similar looking Mnais mneme, a species that has pterostigmata and thus is easily separated from Vestalaria species upon a closer look). Here a few photos from V. vinnula. This species has longer inferior appendages, unlike V. miao, in which the inferiors are very much reduced. The shape of both the superiors and inferiors is much like those of V. smaragdina from the northern mountains and difficult to separate on the basis of these even on close inspection, but unlike V. smaragdina and very much like V. miao, V. vinnula has darkened crescents along the wingtips. The combination of long inferiors and dark crescents help easily establish its identity.

V. vinnula was described from the Lam Dong Province and subsequently also found further north, near Nha Trang, and, as indicated above, also occurs west of Da Nang. Given its widespread occurrence and the close proximity of some of the locations where it has been seen to the Lao PDR, it is probably not endemic to Vietnam. Apparently is survives well into December and it is thus conceivable it can be observed year round.

Vestalaria vinnula male. Note the darkened crescents on the wing apex and the in this photo just visible obvious lower appendage.
Appendages in lateral view. In this way it cannot be separated from V. smaragdina (on ventral or dorsal view it can, but not with ease), but the combination with the wing pattern helps clinch the ID.
Another male, this specimen with some pruinosity on the ventral side, very much like hyaline-winged Mnais mneme, which lacks the dark crescents and has dark pterostigmata.

Saturday, 23 January 2016

Euphaea cyanopogon - an unexpected addition to the Vietnamese list*

*This article was adjusted August 5, 2019, as a result of the publication of a new species Euphaea cyanopogon Hämäläinen, Kosterin & Kompier, 2019. I retain the original text, but the species E. pahyapi is distinct differences with the present species, which now has been described as a new species.

On December 30 I was surveying streams in the forest at the northern side of Phu Quoc island when I noticed a smallish Euphaea species with uniform amber-colored wings. Because E. ochracea had been reported from the island from previous surveys and one of the reports showed a similar amber-colored winged specimen, for the time being I assumed it was this species. But at home checking it against the few specimens that I possess and many photos, both from myself and on the web, the suspicion rose that this really could not be E. ochracea. Not only in outward appearance was it different, but also structurally, like the caudal appendages and the vesicula seminalis. When I caught on to the fact that all adult males of species known from Vietnam have a completely dark face, whereas the Phu Quoc species had whitish-blue markings on the labrum and genae, I became convinced it had too be something else, E. pahyapi. In fact the species was not rare, although also not particularly common, but I saw at least 10 spread over several streams and on January 1 and 2 also noticed it in the forest more centrally to the island.

The species displays some very interesting characteristics. The males I saw (and I only saw males) had facial markings in varying degrees of intensity. A large, but centrally split, spot on the labrum and a large spot on the genae, anteriorly with an incursion of black. The wings were rather straight for the genus and with generally similarly shaped fore wing and hindwing. These were evenly colored from base to apex. Although the discoidal cells of the two specimens I collected are not entire (contra Hamalainen 1985), the cubito-anal space had only 2 cross veins in the fore wing of both specimens and 3 (once 2) in the hindwing, contrary to O. ochracea, which has mostly 4 (or even 5). This fits the description by Hamalainen of E. pahyapi. That species, just like my specimens, has a smooth vesicula seminalis, unlike the grooved vesicula of E. ochracea. The prothorax had vague markings in a few younger specimens, but became all black, contrary to ochracea, which has obvious place areas, and the thorax pattern also was much reduced and less rufous. The abdomen moreover was much darker than in ochracea, again fitting E. pahyapi. The measurements (2 specimens) are an exact fit with those given by Hamalainen for pahyapi, for abdomen, fore wing and hindwing (31-33mm; 29mm; 27mm). Especially fore wing tends to be longer in ochracea. And unlike any of the known species from Vietnam, but in line with E. pahyapi, S3 is adorned with a large area of long hairs. The caudal appendages are rather triangular in outline in lateral view, rather than rectangular.

E. pahyapi was described by Matti Hamalainen in 1985 from peninsular Thailand. Almost immediately afterwards Asahina published E. khaochongensis, which later was synonymized with E. pahyapi as a junior synonym. This is of particular interest, because in the description of Hamalainen the face is completely black, but in that by Asahina the labrum, genae and anteclypeus are all described as dirty blue. As almost all characteristics fit E. pahyapi, it seems quite sufficient to identify it as such. The only obvious difference is the pattern of the face, but given the description of its synonym E. khaochongensis, this is apparently within the range of variability. The other minor difference is that the discoidal cell in both collected specimens has one or two cross veins in all the wings, not entire as was the tendency for Hamalainen's specimens. Of course DNA analysis or further research may still identify the Phu Quoc population as different from that of the Malay Peninsula, but for now the identity of this species as E. pahyapi, not E. ochracea, seems well supported.

IUCN lists E. pahyapi as vulnerable, known from just 3 locations in Thailand and under threat of habitat destruction. As such, its discovery on Phu Quoc in good numbers is very relevant.

Male Euphaea pahyapi. Note the wings of almost similar wit and length, uniformly amber in color. This individual still with yellow-brown spots on prothorax and near ocelli. Also note that dorsal stripes are almost obscured and mesepimeron lacking the stripe bordering the humeral suture.
Another male, with dorsal stripe completely obscured, antehumeral stripe much diminished and mesepimeron with only a reduced stripe along the interpleural suture. This individual with completely black prothorax and cranium.
Close-up of S3 with the mass of long hairs on the proximal half
Close-up of the superior caudal appendages, showing their triangular shape, widest close to the base.
Close up of the smooth vesicula seminalis (left in the picture)
Close-up of facial pattern of one male, with extensive bluish white adjacent to the compound eyes, large bluish-white patches on the genae and on the labrum, and paler brown on the anteclypeus.
Another male, in which the markings are much reduced, especially adjacent to the eyes, but also split into two parts now on the labrum.

Friday, 15 January 2016

Prodasineura mayhem in Cat Tien

James Holden is still in Cat Tien National Park and has expanded his search for Odonata to now also include damsels. Amazingly, he found three Prodasineura species in addition to the two species already known from the park. One of these was at the top of my wish list for 2015 (and the one I failed to see), another is a species described as recently as 2015 by Oleg Kosterin from Cambodia, and the third is a species that I also recently recorded from Phu Quoc and that may well be part of a complex of species that still needs sorting out. I will introduce all three here.

The first wonderful species is Prodasineura doisuthepensis. This smashing species was described in 2007 by Hoess from Thailand. Although the IUCN red list suggests it may be the junior synonym of P. auricolor, it has now been recorded from Vietnam and from Cambodia and appears to be a solid species. Not only are males distinctively different in coloration and shape of markings on their cranium, females too are differently colored. The specimen I already published on my blog (photographed by Toan) has relatively restricted blue dorsal markings and seems to also have less extensive blue on the cranium, so it is possible that another blue-marked species is in play. The specimens from Cat Tien are identical to those from Thailand.

Prodasineura doisuthepensis, photo courtesy of James Holden
Another male, courtesy of James Holden
In hand shot, courtesy of James, showing extent of blue on thorax and head
If the discovery of this dream damsel was not enough, one day James was taking its picture (see the second one above), when another species of Prodasineura flew into the frame. This turned out to be Prodasineura verticalis. Having said that, the P. verticalis from the north of Vietnam has much reduced markings on the dorsum of the thorax and it is possible these are in fact different species. I saw the same species also on Phu Quoc, but failed to make decent pictures.

"Southern" Prodasineura verticalis, Phu Quoc. Note black appendages.

Prodasineura verticalis, southern type, Cat Tien (courtesy James Holden). Note the pale appendages.
Immature male P. verticalis from Phu Quoc. White appendages and pale eyes.
And last, but not least, wonderful Prodasineura hoffmanni, described in 2015 by Oleg from Cambodia, albeit within walking distance of the border with Vietnam. Apparently it has also been recorded from Vietnam by Toan. A distinctive and very beautiful species.

Prodasineura hoffmanni from Cat Tien, courtesy James Holden

Prodasineura hoffmanni in hand, courtesy of James

And the same male, dorsal shot, by James. It looks somewhat darker here.

Tuesday, 12 January 2016

Indothemis limbata - new to Vietnam

On January 1 on Phu Quoc we checked a man-made pond close to the dam that closes off the Duong Dong Reservoir. A heavily vegetated pond, it had many dragonflies of a wonderful diversity of species.  My attention was drawn to a blue-and-black horizontally perching dragonfly that reminded me of a pond hawk Erythemis. This being south-east Asia, that of course was impossibly. Excited I got closer to it and recognized Indothemis limbata, a little recorded species known from India and Sri Lanka in the west to Thailand in the east (where Dennis Farrell has recorded it commonly in some places). It had not been recorded from Vietnam until now. Only recently (Ellenrieder et al., 2014) had its congener I. carnicata been recorded from Vietnam. This species has been found at little used swimming pools, indicating a preference for still, but deep, water with rocky surroundings. I. limbata appears to prefer heavily vegetated ponds. It is easily recognized by its blackish body, blackish-brown basal patches to the hind wings (with some limited marking of the forewings) and bluish pruinose abdomen. Although I saw at least 5-6 different males, I did not see any females.

A male in strong sunlight

Another male. Note the darkened wingtip crescents.

In dorsal view the dark brown basal patches to the hind wings are obvious

Friday, 8 January 2016

Gynacantha bayadera - yet another Gynacantha (species 9)

I had long been looking out for Gynacantha bayadera in Vietnam. According to the IUCN website it is a widespread species, occurring from India to the south of China. Is is mentioned as native to Vietnam. However, until now I had not been able to find it. After James found Gynacantha khasiaca, albeit probably at least a new subspecies, at Cat Tien, the tally for Gynacantha species recently in Vietnam was already at 8. This includes the record by Ellenrieder et al. of Gynacantha hyalina from Cuc Phuong. On January 1 I finally caught up with a female Gynacantha bayadera, easily identified by the apple green thorax and face and plain frons (no T-mark) near Duong Dong lake on Phu Quoc. The next evening I also caught a male along a forest road at the north side of the island (where it flew with G. basiguttata and G. subinterrupta). Clearly it is not a rare species on the island. The male too is try green, with unmarked frons.

Male Gynacantha bayadera, a pretty, very green, small species
The female, likewise very green
The appendages of the male
And the (almost) unmarked green frons

Wednesday, 6 January 2016

Mortonagrion falcatum - an addition to the Vietnamese list

On January 2 I revisited the area around Lake Duong Dong, located centrally on Phu Quoc. The previous day had been quite productive and I was hoping to find a few more additional species for the holiday list. We had found a trail into the forest that after a bit of a hike crossed a stream and it was there that I noticed perched at the tip of a small stick over dead leaves just above the ground by the side of the stream a tiny damsel. Because of its drab basic coloration I thought it was a female and also it did not have obvious appendages in dorsal view. But just as I was getting ready to take better shots my foot slipped a bit and it darted off. Because it was both drab and tiny I immediately lost it. I searched for a long time for additional specimens, but could not find any. Disillusioned, I continued the hike for a while, but on the way back revisited the place and again searched high and low, to no avail. Before leaving even more disillusioned I rechecked the place of the original sighting and there it was! Tiny and inconspicuous, back at its stick. I crawled down next to it and took some photos. But when I wanted to pounce on it, it again darted off into another dimension. The thing was: when I checked the photos (in the middle of shooting) it was a male! I did my best to get as good a close-up of the appendages and this saved the day.

I knew I had seen something like it on some website somewhere and just started leafing through Coenagrionidae. Yes, of course, Mortonagrion! But the first logical suspect, with a sort of similar abdominal pattern, M. arthuri, has rather different appendages. But eventually I found it in Lieftinck (1934): Mortonagrion falcatum. Recognizable by its strange, quite distinctive, appendages. Records are scarce, but it is a widely distributed species, occurring in Indonesia, Singapore, Malaysia, Myanmar, Thailand and with a record from Lao PDR. On the IUCN Red List it is hypothesized that it occurs in Cambodia and Vietnam. Well, it does (in Vietnam, but given the location of Phu Quoc it is highly likely it also occurs in Cambodia. See the pictures below of this interesting midget.

Not a very conspicuous little insect at all, when it perches over brown leaves, but actually rather pretty: Mortonagrion falcatum

The distinctive appendages, the superiors broad and up slanting.

Tuesday, 5 January 2016

A Christmas safari - Da Lat - Con Dao - Phu Quoc

For a Christmas break Kameliya and I travelled to Da Lat, Con Dao and Phu Quoc. The first was good for 12 dragonfly species, the second for about 25 and the latter for 63. Needless to say, we were looking for a lot more than dragonflies, so this was not disappointing. Phu Quoc was out of season for some of the specialties, but with 63 species in 4 days of searching we still topped the 2007-2008 survey by Bui Huu Manh and its successor from 2011 by Do Manh Cuong et al. Floris Brekelmans in March 2015 found several additional species (notably Podolestes coomansi and Coeliccia kazukoae), so it was not surprising that there were still a few species that remained to be discovered.

On the list as given by Do et al. (2011) there are several species that were already present on the list of Bui, but judging from the photos in his photographic guide some of these are misidentifications. (Copera marginipes is clearly C. vittata, Cratilla lineata is Potamarcha congener, supposed Cratilla metallica looks to be Lathrecista asiatica, Ceriagrion auranticum looks to be C. calamineum, and Euphaea ochracea appears to be E. pahyapi.) Do et al. moreover suppose that the weird thoracic markings of Coeliccia yamasakii in Bui indicate a species novum, but I consider these immature examples of typical C. yamasakii. The unidentified Prodasineura is very similar to P. verticalis from southern Thailand and for the moment I treat it as such. This is not to diminish the value of their pioneering work. They did much to map the beauty of the Odonate fauna of Phu Quoc, which is under severe threat from the break-neck speed of the development of the island. Waterways are getting polluted and depleted, wetlands drained and build-up. Clearly environmental considerations are not keeping up with the urge to make a quick buck.

I will over the next days publish photos of some of the species found. Here I limit myself to my list of Phu Quoc and photos of wonderful Rhinagrion viridatum, a highlight of the trip. This species was recorded as Rhinagrion mima, but Kalkman & Villanueva (2011) already pointed out that the inclusion of R. viridatum in R. mima should be revised and R. viridatum given full species status.

The first of 7 males of beautiful Rhinagrion viridatum

Another male of the same smashing species

The List:

Vestalis gracilis
Libellago hyalina
Heliocypha biforata
Euphaea pahyapi****
Ischnura senegalensis
Aciagrion borneese
Agriocnemis minima*
A. nana*
A. pygmaea
Archibasis viola
Ceriagrion cerinorubellum
C. olivaceum*
Mortonagrion falcatum***
Pseudagrion australasiae*
P. microcephalum
P. rubriceps
P. pruinosum
P. williamsoni
Coeliccia kazukoae**
Pseudocopera ciliata*
Copera vittata**
Prodasineura verticalis**
Anax guttatus
Gynacantha basiguttata*
G. bayadera*
G. subinterrupta*
Ictinigomphus decoratus meleanops
Paragomphus capricornis*
Epophthalmia frontalis*
Acisoma panorpoides
Crocothemis servilia
Orthetrum sabina
O. neglectum*
O. chrysis
Pantala flavescens
Trithemis festiva
T. aurora
T. pallidinervis
Brachydiplax chalybea*
Brachythemis contaminata
Diplacodes nebulosa
D. trivialis
Hydrobasileus croceus
Indothemis limbata***
Lathrecista asiatica
Nannophya pygmaea
Neurothemis fluctuans
N. tullia
N. fulvia
N. intermedia*
Potamarcha congener
Pseudothemis jorina*
Rhodothemis rufa*
Rhyothemis phyllis
R. variegata
R. triangularis
Tetrathemis irregularis
Tholymis tillarga
Tramea transmarina euryale*
Urothemis signata
Zygonyx iris
Zyxomma petiolatum*
Rhinagrion viridatum

*   Refers to species first recorded on the island, although some are very common
** Coeliccia kazukoae had already been found by Floris Brekelmans, but is not rare. Prodasineura verticalis had been recorded as Prodasineura sp. Copera vittata had been misidentified previously (as C. marginipes), but is a very common species.
*** Refers to species recorded for the first time for Vietnam (as far as I know)
**** Refers to a species recorded for the first time for Vietnam, but misidentified in previous surveys.