Sunday 15 March 2009

Raphismia bispina

Species Name: Raphismia bispina
Family: Libellulidae


Last week on a short visit to the Borneo Paradise Eco-resort near Lahad Datu, Sabah I saw and photographed a small female libellulid on the mangrove edge which I had never seen before. When Rory Dow saw the photo which I emailed to him he said it looked like the female of Raphismia bispina a mangrove specialist. On checking the books and on the Net I found out that the male is a small blue fellow that resembles Brachydiplax chalybea, and I suddenly recalled seeing what I thought was a very skittish B. chalybea at the same place.

Male guarding a pond

Well, today I went to look for this male and found quite a few of them in the mangrove forest at the resort. Almost every small tidal pond (of salt water) has at least one male guarding it. And I also saw a female ovispositing in one of the ponds jealously guarded by the resident male.

Male perched on mangrove seedling

At first glance the males look like B. chalybea except that they are a bit smaller and the shade of blue is slightly different. But unlike the latter they are very skittish flying away at the slightest movement and landing further away. It took me quite some time and very patient stalking to get my first satisfactory shot.

I also tried to take some photos of their underside (upskirt photos!!) to try to show the signatory twin spines on their thorax behind the hind legs and the process projecting beneath on segment 2 of the abdomen. See if you can spot these on the photos.

Male, the process on abdominal segment 2 is clearly 
visible, but the pair of spines behind legs are less so

Sunday 1 March 2009

Zyxomma petiolatum

Species Name: Zyxomma petiolatum
Family: Libellulidae


Two species of Zyxomma are quite commonly encountered but are rarely noticed because they are both crepuscular, i.e. they are active only when the sun has set and before sunrise. Z. petiolatum are less often seen or noticed because of its sombre brownish colour, unlike the male Z. obtusum which is covered in a "ghostly" white pruinescence that extents to its wings. 

The two Zyxomma species are very dissimilar, with obtusum being more "libellulid-shaped", while the petiolatum male has a long and very slender abdomen; the female's is somewhat thicker.

Both sexes are active from late afternoon to well into the evening and probably at dawn too as with obtusum, and are attracted to lights; the photos here are of specimens that flew into the house at night.


Said to be widespread in tropical Asia and Australasia.