Anax indicus Lieftinck, 1942

On April 18, 2016, during a general survey along the Red River at Hanoi, I photographed a male Anax patrolling along a little pool. At first glance I thought it was the common Anax guttatus, but something was wrong: 1/the extensive yellow lateral patches on the abdomen. 2/its behavior (quite flyer, often seen hovering). 
When I got home, I did a little research and it turns out to be Anax indicus, a species never recorded in Vietnam.   

This brings the total number of Anax species found in the country to five, the other four being A. guttatus, A. parthenope julius, A. immaculifrons, A. nigrofasciatus. The one to find now is A. panybeus, a wide-ranging species (from Japan to Indonesia) very likely to be present in Vietnam.

Patrolling Anax indicus, Hanoi (with flash, 100mm lens)

Patrolling Anax indicus, Hanoi (without flash, 400mm lens)

                            S4-10 have large, bright dorsolateral yellow-orange markings, obvious even in flight

Anax indicus has a wide distribution in the Indomalayan region. It is known from Nepal, Pakistan, Sri lanka, India, Bangladesh and Thailand. In 2010, it has also been found in Hong Kong, first record from Chinese territory. 
According to the IUCN Red List website, there are holes in its known distribution but these are likely to be due to under sampling and misidentification as the closely related A. guttatus, with which it has frequently been confused.