Witton noted that although bird beaks lose heat quickly, that is not what they were developed for; the crests of pterosaurs might also have had an effect on thermoregulation, without this being their primary function. Pêgas and colleagues noted that sexual dimorphism in crest size and shape has been proposed for some pterosaurs; the crest shape seen in the T. sethi holotype may correlate with one sex and may have been the result of sexual selection. They suggested that both sexes could have had similar crests due to mutual sexual selection, but interpretation of exaggerated features was challenging due to the small sample size; more T. sethi specimens would have to be found to evaluate these theories. They did not think that thermoregulation correlated with crest growth relative to body size, since the bills of toucans (the largest of any modern birds) grow drastically out of proportion to body size and function as thermoregulatory structures, as well as facilitating feeding and social behaviour. Pêgas and colleagues found the vascular structure of toucan bills comparable to that in the crest of T. sethi, concluding that the crest also had multiple functions. Feeding and diet Kellner and Campos originally found the jaws of Thalassodromeus similar to those of modern skimmersthree bird species in the genus Rhynchopswith their sideways-compressed jaws, blade-like beak, and protruding lower jaw (resembling scissors in side view). They argued that Thalassodromeus would have fed in a similar way, as implied by the genus name; skimmers skim over the surface of water, dipping their lower jaw to catch fish and crustaceans. Kellner and Campos listed additional skull features of skimmers which are adaptations for skim feeding, including enlarged palatine bones, a feature also shared with Thalassodromeus. Unlike skimmers and other pterosaurs, the palatine bones of Thalassodromeus were concave, which the writers suggested could have helped it momentarily store food. Like skimmers, Thalassodromeus also appears to have had powerful neck muscles, large jaw muscles, and an upper jaw tip well-irrigated by blood (features which Kellner and Campos interpreted as adaptations for skimming). They concluded that the scissor-like bill and thin crest almost made other modes of capturing preysuch as swooping down toward water and plunging into itimpossible. Conceding the difficulty of reconstructing Thalassodromeuss fishing method, they envisioned it with a less-mobile neck than skimmers; with the crest impeding its head from submersion it would glide, flapping its wings only occasionally. They