User blog comment:Lord Loss/Monster Hunter Theory... Blog/@comment-5020152-20120728010214/@comment-4775842-20120813171220

Well, despite all you guys have said, I believe Khezu and Gigginox are NOT reptiles. It is possible that Khezu and Gigginox split off from the rest of the wyverns, pelagus, and other such beasts long before wyverns ever existed, perhaps even before life on land existed. The ancestral coding would still be in all the resulting evolutions. This may be why Khezu and Gigginox have wings. Not because they evolved from reptilian wyverns, but because their genetic coding (metaphorically) said that it would probably be best to have wings. It is likely that the Khezu and Gigginox are much more closely related to modern leeches than any flightless lizard. While the Tigrex's form of evolution (basically remaining the same for many tens of thousands of years, i.e. like the tuatara) is rare, de-evolution, losing abilities through evolution to gain only rudimentary replacements is even rarer. So, while Khezu and Gigginox can be classified as flying wyverns, they are not closly related to rathalos or kut ku's.