Harpactognathus

Harpactognathus (meaning "seizing/grasping jaw") is a genus of pterosaur, a group of extinct flying reptiles, that lived during the Kimmeridgian stage of the Late Jurassic period in what is now Wyoming, United States. Harpactognathus is confidently known from a single, incomplete rostrum (front of skull) found in 1996 at the Bone Cabin Quarry, though an incomplete mandible (lower jaw bone) and humerus (upper arm bone) from the Quarry have tentatively been referred to Harpactognathus. The rostrum was later described by paleontologist Kenneth Carpenter and colleagues in 2003, who named the type and only known species, H. gentryii, after Joe Gentry, a volunteer for the Western Paleontological Laboratories in Lehi, Utah.

Harpactognathus is a large-sized pterosaur, with an estimated wingspan of 2.5 metres (8.2 ft) and estimated complete skull length of 280–300 millimetres (11–12 in), making it among the largest known non-pterodactyloid pterosaurs. The rostrum of Harpactognathus is robust, broad, and wider than tall. On the midline of the skull is a premaxillary (front upper jaw bone) crest that may have been extended by soft tissues and used for sexual display or sexual dimorphism. Due to a lack of remains, much of its anatomy is unknown and can only be inferred from related taxa. When Harpactognathus was described, it was assigned to the subfamily Scaphognathinae within Rhamphorhynchidae, a group of long-tailed, toothed non-pterodactyloid pterosaurs. It was initially referred to Scaphognathinae, but later discoveries of large rhamphorhynchines like Sericipterus and Angustinaripterus with characteristics found in Harpactognathus suggest it was a member of Rhamphorhynchinae instead. Based on its teeth, robusticity, and origin, Harpactognathus was a terrestrial carnivore that lived near freshwater areas in contrast to the piscivorous lifestyles of relatives like Rhamphorhynchus.

Harpactognathus was found in strata of the Morrison Formation, which bears a variety of other fossils. This includes several other genera of pterosaurs, such as Mesadactylus and Dermodactylus, as well as many unnamed pterosaurs. In addition to pterosaurs, the Morrison Formation preserves fossils of many dinosaurs, including sauropods, theropods, and ornithischians, crocodylomorphs, mammals, lizards, turtles, and more.