Gwawinapterus beardi is known from a single fossil specimen, consisting only of the front half of a skull (upper and lower jaws). The tip of the snout is rounded and deep with a height of about 9.5 centimetres (3.7 in). The tip is about 6.5 centimetres (2.6 in) from the front edge of the largest skull opening, or fenestra. Below this opening the upper jaw is about 21 millimetres (0.83 in) tall. The jaw was originally suggested to be a sutureless fusion of the premaxillae and maxilla of a reptile. Each upper jaw holds at least 26 teeth, eleven or twelve of them below the fenestra; the front of the tooth row has not been preserved and the fossil is broken at its end. The teeth are closely packed. The tooth crowns are small, 4 millimetres (0.16 in) tall and 2.75 millimetres (0.108 in) wide, f