m, 15.5 m, and 21 m, respectively (36 ft, 50.85 ft, 68.9 ft). In 1981, further advanced studies lowered these estimates to . More recent estimates based on greater knowledge of azhdarchid proportions place its wingspan at . Remains found in Texas in 1971 indicate that this pterosaur had a minimum wingspan of about . Generalized height in a bipedal stance, based on its wingspan, would have been at least high at the shoulder. Body mass estimates for giant azhdarchids are extremely problematic because no existing species share a similar size or body plan, and in consequence, published results vary widely. Generalized weight, based on some studies that have historically found extremely low weight estimates for Quetzalcoatlus, was as low as for a individual. A majority of estimates published since the 2000s have been substantially higher, around . In 2021, Kevin Padian and his colleagues estimated that Q. lawsoni would have weighed for individuals with a wingspan of . In 2022, Gregory S. Paul estimated that Q. lawsoni had a wingspan of , body length of , and body mass of . Skull Skull material from Q. lawsoni shows that Quetzalcoatlus had a very sharp and pointed beak. That is contrary to some earlier reconstructions that showed a blunter snout, based on the inadvertent inclusion of jaw material from another pterosaur species; this material was named as the holotype of a genus of short-snouted azhdarchid, Wellnhopterus, in 2021. A skull crest was also present but its exact form and size are still unknown. Classification Below is a cladogram showing the phylogenetic placement of Quetzalcoatlus within Neoazhdarchia from Andres and Myers (2013). Paleobiology Quetzalcoatlus was abundant in Texas during the Lancian in a fauna dominated by Alamosaurus. The Alamosaurus-Quetzalcoatlus association probably represents semi-arid inland plains. Quetzalcoatlus had precursors in North America and its apparent rise to widespreadness may represent the expansion of its preferred habitat rather than an immigration event, as some experts have suggested. It co-existed with another azhdarchid known as Wellnhopterus, as well as an additional pterosaur taxon, suggesting a relatively high diversity of Late Cretaceous pterosaur genera. Feeding There have been a number of different ideas proposed about the lifestyle of Quetzalcoatlus. Because the area of the fossil site was removed from the coastline and there were no indications of large rivers or deep lakes nearby at the end of the Cretaceous, Lawson in 1975 rejected a fish-eating