reaching in length and in body mass. Skull The snout of Hauffiopteryx is short, but also very thin, tapering to a point. The outer surface of the tooth crowns is smooth, and the back teeth are larger than those in front. The upper jaw is slightly longer than the lower jaw, though this overbite is not carried to the extreme seen in Excalibosaurus and Eurhinosaurus. The nasals form the majority of the snout’s midline, rather than the premaxillae (upper tooth-bearing bones). In H. altera, the tallest points of the maxillae (rear upper tooth-bearing bones) are positioned behind the external nares (openings that housed the nostrils), in contrast to H. typicus, where the tallest points are instead located beneath these openings. Part of the borders of the external nares are formed by the prefrontals (paired bones situated on the upper edges of the eye sockets). In H. altera, this configuration blocks the lacrimals (paired bones in front of the eye sockets) from forming part of the external nares, whereas the lacrimals do reach the external nares in H. typicus. A further difference between the two species lies in the shape of their lacrimals; in H. typicus, the are triradiate, while those of H. altera are massive and triangular. The orbits (eye sockets) of H. typicus are especially large and circular. In front of the orbits, the nasals of H. typicus curve upwards. The nasals extend further back in H. altera than in H. typicus, though the nasals of Hauffiopteryx do not touch the parietals (a pair of skull roof bones). Externally, the prefrontals have greater surface area than the postfrontals, especially so in H. altera. The frontals (a pair of skull roof bones) form most of the border of the pineal foramen, a small opening on the midline of the skull. Instead of being in line with the front edges of the supratemporal fenestrae (paired openings on the top of the skull’s rear), the foramen is instead located in front of them. The supratemporal fenestrae themselves are rounded and small. The supratemporals (paired skull roof bones) have wavy edges. Behind the orbits, the skull is short from front to back, with the cheek region deflected so that it faces backwards. The rear face basioccipital (braincase bone to which the vertebral column attaches) bears a considerable amount of surface which is not involved in the joint between the skull and the spine.