Monday, November 30, 2009

Orthetrum testaceum vs Orthetrum chrysis

In Peninsular Malaysia, Orthetrum testaceum and O. chrysis are quite common red dragonfly species. They look alike and occupy the same habitats - pond, lake and garden. They may appear side by side at the same habitat. How do differentiate them? Well, experienced odonate workers will be able to tell them apart immediately. First, the body colour (particular the thorax) of O. testaceum is much reddish than O. chrysis. Instead, O. chrysis has reddish brown thorax. Apart from that, the size of O. testaceum is slightly larger than O. chrysis. Well, if doubt arises, the best characteristic to distingiush these two species is by investigating their genitalia. O. chrysis has a tuft of setae at the genitalia but O. testaceum lacks of this.

O. testaceum

O. chrysis