The bony labyrinth of the inner ear crocodylomorphs became more compact and thicker as they are from semi-aquatic animals evolved into sea creatures, reported in the Proceedings of the National Academy of Sciences. Cetaceans — mammals, who also became vtorichnoe, which is similar to the transformation of the bony labyrinth began after they moved to a fully aquatic lifestyle.
Vertebrates arose in the water, but then part of them came on to land. A portion of the land has mastered the air (learned to fly, or at least plan), and part again went into the water. The most recent and most studied example of the transition to vtorichnogo — cetaceans. Representatives of this group steel water population of about 45 million years ago, preserved many of their remains, allowing sufficient detail to restore the anatomical changes that occurred in that time.
To whales the niche of large aquatic (primarily marine) predators took the most diverse groups of reptiles: plesiosaurs, ichthyosaurs, a number of crocodylomorphs and others. Most of them lived in the Mesozoic (up to the present day survived only one branch of crocodylomorphs squad crocodiles), that is at least 66 million years ago. Their bodies remained on average not as good as the remains of ancient cetaceans. Therefore, the adaptations that allowed prehistoric reptiles go into the water, not much is known.
An international team of paleontologists led by Julia Schwab (Julia Schwab) the University of Edinburgh explored how varied the ancient crocodylomorphs the structure of the bony labyrinth of the inner ear. The inner ear is responsible for hearing and balance, and they depend on the density of the medium in which the animal is located. Since water is denser than air, to hear and to maintain the correct body position land the inner ear does not work.
The bony labyrinth is signed three semicircular canal (part of vestibular apparatus) and the cochlea (the ear provides). The form of this education was studied by the paleontologists. To this end they established by computed tomography three-dimensional reconstruction of skulls 13 thalattosuchia — extinct marine crocodylomorph the Jurassic period, and Protosuchus haughtoni, Eopneumatosuchus colberti, upper Cretaceous of neosuchia Shamosuchus djadochtaensis and 14 modern representatives of the order of crocodiles. The researchers then compared the proportions of specific parts of the bony labyrinths of different types and take into account their systematic position, and what is known about the ecology of these crocodylomorphs.