Male Nychogomphus lui, Hanoi, on June 15, 2011
An enigma finally resolved thanks to Tom Kompier who
recently sent me an email with a link to a Chinese website, with these words: “have a look
at the photo with caption Nychogomphus lui”. I opened the link and immediately
recognized a familiar Gomphid, one of the 3 mysterious Gomphids species I encountered 1,5 km from downtown Hanoi in 2011 and 2012. An unidentified species that not only puzzled me but
also experienced odonatologists.
Just after receiving Tom’s email, I checked the original description by Zhou & al., 2005, which confirmed its identity.
Just after receiving Tom’s email, I checked the original description by Zhou & al., 2005, which confirmed its identity.
But let’s go back to mid-June 2011 : during a noon stroll at
Hanoi, I bumped into a medium-sized male Onychogomphine resting on leaves 50cm
above the ground, in a tiny wooded area surrounding a small pond. A very
polluted pond I must say, located 1,5 km from the city center and 400m from the Red River
– the large river that runs along the city. At that time, I was interesting by
Odonata for only few months – so a complete novice. After some shots in
hand, I released it (big mistake...), convinced that in such a place it could
not be something else than a very common species, easy to identify. If I had
known that it was a new species for the country, the story would have been very
different!
Some of the pictures displayed here are quite bad, I apologize for that. They were taken 3 years ago with my first camera.
Some features of the male Nychogomphus lui :
-head well marked (labrum with pair of elongated yellow spots, anteclypeus, base of mandibles yellow, split yellow line over frons).
-synthorax black with a yellow dorsal stripe connected
to the collar stripe to form a broad 7-shaped mark, superior yellow
antehumeral spot, sides of synthorax marked with broad yellow stripes.
-basal part of abdominal segments 4-7 all ringed completely [broader basal ring on S7], S7-9 broadly expanded.
-superior appendages whitish, brownish-tipped, the apical half curved downwards, slightly longer than the inferiors, the latter undulant curved, bifid almost to base, the two branches very closely apposed, curved strongly up to meet the superior appendages.
-basal part of abdominal segments 4-7 all ringed completely [broader basal ring on S7], S7-9 broadly expanded.
-superior appendages whitish, brownish-tipped, the apical half curved downwards, slightly longer than the inferiors, the latter undulant curved, bifid almost to base, the two branches very closely apposed, curved strongly up to meet the superior appendages.
Male, frontal view showing the broad dorsal 7-shaped marks on the
synthorax.
I also did manage some record shots of the female. She display a similar color pattern to the male.
The female. Note the basal part of abdominal segments 4-7 all ringed
completely (broader ring on S7) as
the male.
Nychogomphus lui has been described in 2005 from Yunnan. As far as I
know, this record from Hanoi is the first one outside China. According to Dr
Haomiao Zhang (pers. comm.), Nychogomphus lui breed in rivers and streams. So
the specimens I encountered came certainly from the Red River (about 700-800m wide at Hanoi) and it
is probably the case of the 2 other unknown Gomphids found at the same polluted
pond – among them a female Stylurus sp., members of this genus in Asia
generally prefer broad, deep, slow flowing rivers.
And believe me, Hanoi is far from being a “green city”!...
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