the crests of Tupuxuara and its relatives developed by the premaxillary portion of the crests growing backwards over the skull-roof (as indicated by the well-defined suture between the premaxilla and the underlying bones). The hind margin of the premaxillary part of this specimen's crest had only reached above the hind margin of the nasoantorbital fenestra, indicating that it was not an adult at the time of death. This suggests that the development of the crest happened late in the growth of an individual, was probably related to sexual display, and the sexual maturity of a given specimen could be assessed by the size and disposition of the crest. The T. sethi holotype, with its hypertrophied (enlarged) premaxillary crest, would thereby represent an old adult individual (and the mature stage of Tupuxuara, according to their interpretation). Kellner and Campos found Martill and Naish's discussion of cranial crest development interesting, although they found their proposed model speculative. Palaeontologists David W. E. Hone, Naish, and Innes C. Cuthill reiterated Martill and Naish's growth hypothesis in 2012; since pterosaurs were probably precocial and able to fly shortly after hatching, the role of the crest was relevant only after maturity (when the structure was fully grown). They deemed the thermoregulation hypothesis an unlikely explanation for the blood-vessel channels on the crest, which they found consistent with nourishment for growing tissue (such as the keratin in bird beaks). Hone, Naish, and Cuthill suggested that the wing membranes and air-sac system would have been more effective at controlling heat than a crest, and wind and water could also have helped cool pterosaurs in high-temperature maritime settings. In 2013, Witton agreed that the substantially larger crests of adult thalassodromids indicated that they were more important for behavioural activities than for physiology. He found the idea that the crests were used for thermoregulation problematic, since they did not grow regularly with body size; they grew at a fast pace in near-adults, quicker than what would be predicted for the growth of a thermoregulatory structure. According to Witton, the large, highly vascular wing membranes of pterosaurs would provide the surface area needed for thermoregulation, meaning the crests were not needed for that function. He concluded that the crest's blood-vessel patterns did not differ much from those seen on bones under the beaks of birds, which are used for transporting nutrients to the bone and soft tissues rather than for thermoregulation.