Reconstruction of the neck of Azhdarcho lancicollis and lifestyle of azhdarchids (Pterosauria, Azhdarchidae)

A computer reconstruction of isolated cervical vertebrae of Azhdarcho lancicollis from the Turonian of Uzbekistan allows three-dimensional model of the cervical region of the vertebral column of this animal. The relative length of cervical vertebrae (I + II < III < IV < V > VI > VII > VIII > IX) is the same as in pterodactyloids with short cervical vertebrae. An increase in neck length is provided mostly by the middle cervical vertebrae (IV–VI). In a neutral posture, the neck of azhdarchids was not straight, as often reconstructed, but S-shaped, with the maximum angles between the V–VI (20°), VI–VII (20°), and VIII–IX (17°) vertebrae. The feeding strategy of azhdarchids was probably similar to that of pelicans. In a search for prey, azhdarchids were soaring above the water surface of large inland or nearshore marine water bodies. Their prey (predominantly fish) was captured by the widely open mouth and fell into the throat sac, the presence of which is suggested by the spiral jaw joint. Prey was swallowed during the abrupt neck flexion in the posterior segment, which brought the head in an almost horizontal position. A storklike wading ecology for azhdarchids is less probable, because these clumsy on land animals were vulnerable to terrestrial predators.