Ictinogomphus pertinax (Hagen in Selys, 1854)

Ictinogomphus pertinax is a common large-sized and powerful gomphid, found in still waters. That's a gorgeous creature; I find it interesting to observe, beautiful to look – head down poses are great!

This species can be found in very disturbed habitats. I spotted it flying over marshy areas, large tanks or tiny ponds surrounded by rice fields or wooded areas, sluggish rivers, slow-flowing portion of swift streams... But I never saw it on ponds with cemented beds, where Sinictinogomphus clavatus can occur.

Will it slip off and fall headfirst into the water ?

Ictinogomphus pertinax often be seen perched on a prominent twig or stick facing the water, head inclined downwards and abdomen held well up.
Should it be disturbed either by a rival, a passing female or by a curious human like me, it usually returns to its resting place, again and again, or settles close by until the danger is past, when it again returns to its first resting place.

Wow! You wouldn't want to argue with this brute!

I like the way this guy (pic above) hold on to its perch. Hind legs grip the stick tight and the mid-legs just stabilize the body. Most of the time – but not in this shot because it was grabbing its lunch -, it hold its front legs folded behind the head.

Note the big hole on the side of the synthorax (metepimeron area, if I am not wrong). Maybe he was injured during a fight against a rival. Unlike most gomphids, the males frequently engage in fierce combat, especially if females are frequenting their area.

Female has a more robust and shorter abdomen but differs mainly from the male in sexual characters.

Bugs Bunny, dragonfly version

According to Fraser (The Fauna of British India, including Ceylon and Burma - Odonata, 1933), I. pertinax differs from I. rapax (also present in Vietnam, but maybe less common (?), at least in the North) in the black anteclypeus, the abdominal 8th segment (the one with 2 leaf-like expansions) with lateral spots - instead of a basal ring - and the 10th segment entirely black. Surprisingly, those two species have caudal appendages shaped similarly.

Lateral view of the last abdominal segments of a male

I don’t know if there are other key features – structural those ones – to tell apart those 2 species ; if you know, please tell me!

Ictinogomphus pertinax is widely distributed from Japan, China, Taiwan to Vietnam, Laos, Myanmar and eastern India; although records from those two last countries may not refer to this species but to variants of either I. rapax or I. decoratus (source : www.iucnredlist.org).

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