Quick-and-dirty drawing of a monster I've had in mind for a while. Man did I go crazy with the colors here.

The Quetsukos, often referred to as the masked wyvern, is a flightless member of the wyvern family heavily adapted to its jungle habitat. It is theorized that the density of trees in the jungle made flight impractical for a creature of a wyvern's size; instead, their wings developed into elongated foreclaws that the Quetsukos whips at foes, catching them off guard with their extended reach. Their moniker "masked wyvern" originates from their unusual beaks. The enamel surface of a Quetsuko's beak extends out to cover their entire upper skull, producing a sort of natural "mask". The reason for this adaptation is unknown, but common belief is that the mask helps protect the wyvern's face from cuts sustained in territorial disputes with other members of the species.