A fellow called Jonathan Whitcomb is the leading researching authority in this field. He has a creationist agenda which unfortunatly taints the strong effort he puts into attempting to uncover these cryptids.
No to be confused with the suspected Giant Flying Fox cryptid, the Ahool, the ropen is a suspected surviving species of Pterosaur supposedly found as Rosenrot has stated, PNG, they are also supposed to exist in Africs (by name of Kongamato) and South America. Some theorise Mothman is a Pterosaur.
Here you can find the esteemed Mr. Whitrcombs site, I recommend it, far be it from me to promote creationism in any way whatsoever, however, the large amount of evidence this fellow has gathered is very impressive. To see the adverse conditions one must undertake in order to search these habitats, one can at least admire the determination and conviction.
There are several interviews with PNG naitives and some compelling evidence in relation to the Bioluminesence the creatures are said to emit at night. There is a tale or two of them stealing carrion as well. It is interesting that te naitives are actually describing the diet of the creature to be remarkably similar to what paleontologists theorise Pterosaurs diet was. The site is a thourough one and a good read.
Interesting cryptid. Quite some reports have surfaced.