Inner ear sensory system changes as extinct crocodylomorphs transitioned from land to water

• Autores: Schwab, Julia A.; Young, Mark T.; Neenan, James M.; Walsh, Stig A.; Witmer, Lawrence; Herrera, Laura Yanina; Allain, Ronan; Brochu, Christopher A.; Choiniere, Jonah N.; Clark, James M.; Dollman, Kathleen N.; Etches, Steve; Fritsch, Guido; Gignac, Paul M.; Ruebenstahl, Alexander; Sachs, Sven; Turner, Alan H.; Vignaud, Patrick; Wilberg, Eric W.; Xu, Xing; Zanno, Lindsay E.; Brusatte, Stephen L.
• Año de publicación: 2020
• Idioma: inglés
• Tipo de recurso: artículo
• Materia: BONY LABYRINTH; CT SCANNING; MORPHOLOGY; THALATTOSUCHIA; VESTIBULAR SYSTEM
• Institución: Consejo Nacional de Investigaciones Científicas y Técnicas

Major evolutionary transitions, in which animals develop new body plans and adapt to dramatically new habitats and lifestyles, have punctuated the history of life. The origin of cetaceans from land-living mammals is among the most famous of these events. Much earlier, during the Mesozoic Era, many reptile groups also moved from land to water, but these transitions are more poorly understood. We use computed tomography to study changes in the inner ear vestibular system, involved in sensing balance and equilibrium, as one of these groups, extinct crocodile relatives called thalattosuchians, transitioned from terrestrial ancestors into pelagic (open ocean) swimmers. We find that the morphology of the vestibular system corresponds to habitat, with pelagic thalattosuchians exhibiting a more compact labyrinth with wider semicircular canal diameters and an enlarged vestibule, reminiscent of modified and miniaturized labyrinths of other marine reptiles and cetaceans. Pelagic thalattosuchians with modified inner ears were the culmination of an evolutionary trend with a long semiaquatic phase, and their pelagic vestibular systems appeared after the first changes to the postcranial skeleton that enhanced their ability to swim. This is strikingly different from cetaceans, which miniaturized their labyrinths soon after entering the water, without a prolonged semiaquatic stage. Thus, thalattosuchians and cetaceans became secondarily aquatic in different ways and at different paces, showing that there are different routes for the same type of transition.
Fil: Schwab, Julia A.. University of Edinburgh; Reino Unido
Fil: Young, Mark T.. University of Edinburgh; Reino Unido
Fil: Neenan, James M.. University of Oxford; Reino Unido
Fil: Walsh, Stig A.. University of Edinburgh; Reino Unido
Fil: Witmer, Lawrence. Ohio University; Estados Unidos
Fil: Herrera, Laura Yanina. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. División Paleontología Vertebrados; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata; Argentina
Fil: Allain, Ronan. Muséum National d'Histoire Naturelle; Francia
Fil: Brochu, Christopher A.. University of Iowa; Estados Unidos
Fil: Choiniere, Jonah N.. University of the Witwatersrand; Sudáfrica
Fil: Clark, James M.. The George Washington University. Columbian College Of Arts And Sciences. Department Of Biological Sciences.; Estados Unidos
Fil: Dollman, Kathleen N.. University of the Witwatersrand; Sudáfrica
Fil: Etches, Steve. Museum of Jurassic Marine Life; Reino Unido
Fil: Fritsch, Guido. Leibniz Institute For Zoo And Wildlife Research.; Alemania
Fil: Gignac, Paul M.. Oklahoma State University; Estados Unidos
Fil: Ruebenstahl, Alexander. University of Yale; Estados Unidos
Fil: Sachs, Sven. Natural History Museum, Bielefeld ; Alemania
Fil: Turner, Alan H.. Stony Brook University ; State University Of New York;
Fil: Vignaud, Patrick. Stony Brook University ; State University Of New York;
Fil: Wilberg, Eric W.. Stony Brook University ; State University Of New York;
Fil: Xu, Xing. Chinese Academy of Sciences; República de China
Fil: Zanno, Lindsay E.. North Carolina State University; Estados Unidos
Fil: Brusatte, Stephen L.. University of Edinburgh; Reino Unido