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Wang YY, Claessens LPAM, Sullivan C. Deep reptilian evolutionary roots of a major avian respiratory adaptation. Commun Biol 2023; 6:3. [PMID: 36650231 PMCID: PMC9845227 DOI: 10.1038/s42003-022-04301-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2022] [Accepted: 11/25/2022] [Indexed: 01/19/2023] Open
Abstract
Vertebral ribs of the anterior thorax in extant birds bear bony prongs called uncinate processes, which improve the mechanical advantage of mm. appendicocostales to move air through the immobile lung and pneumatic air sacs. Among non-avian archosaurs, broad, cartilaginous uncinate processes are present in extant crocodylians, and likely have a ventilatory function. Preserved ossified or calcified uncinate processes are known in several non-avian dinosaurs. However, whether other fossil archosaurs possessed cartilaginous uncinate processes has been unclear. Here, we establish osteological correlates for uncinate attachment to vertebral ribs in extant archosaurs, with which we inferred the presence of uncinate processes in at least 19 fossil archosaur taxa. An ancestral state reconstruction based on the infer distribution suggests that cartilaginous uncinate processes were plesiomorphically present in Dinosauria and arguably in Archosauria, indicating that uncinate processes, and presumably their ventilatory function, have a deep evolutionary history extending back well beyond the origin of birds.
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Affiliation(s)
- Yan-yin Wang
- grid.17089.370000 0001 2190 316XDepartment of Biological Sciences, CW 405 Biological Sciences Building, University of Alberta, Edmonton, AB T6G 2E9 Canada
| | - Leon P. A. M. Claessens
- grid.5012.60000 0001 0481 6099Maastricht Science Programme, Faculty of Science and Engineering, Maastricht University, Maastricht, The Netherlands
| | - Corwin Sullivan
- grid.17089.370000 0001 2190 316XDepartment of Biological Sciences, CW 405 Biological Sciences Building, University of Alberta, Edmonton, AB T6G 2E9 Canada ,Philip J. Currie Dinosaur Museum, Wembley, AB T0H 3S0 Canada
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Riguetti FJ, Apesteguía S, Pereda-Suberbiola X. A new Cretaceous thyreophoran from Patagonia supports a South American lineage of armoured dinosaurs. Sci Rep 2022; 12:11621. [PMID: 35953515 PMCID: PMC9372066 DOI: 10.1038/s41598-022-15535-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2021] [Accepted: 06/24/2022] [Indexed: 11/24/2022] Open
Abstract
The early evolution of thyreophoran dinosaurs is thought to have occurred primarily in northern continents since most evidence comes from the Lower and Middle Jurassic of Europe and North America. The diversification into stegosaurs and ankylosaurs is obscured by a patchy fossil record comprising only a handful of fragmentary fossils, most with uncertain phylogenetic affinities. Here we report the discovery of a new armoured dinosaur from the early Late Cretaceous of Argentina, recovered phylogenetically using various datasets either as a basal thyreophoran or a stem ankylosaur, closely related to Scelidosaurus. It bears unusual anatomical features showing that several traits traditionally associated with the heavy Cretaceous thyreophorans did not occur universally. Jakapil kaniukura gen. et sp. nov. is the first definitive thyreophoran species from the Argentinian Patagonia. Unlike most thyreophorans, it seems to show a bipedal stance, as in Scutellosaurus. Jakapil also shows that early thyreophorans had a much broader geographic distribution than previously thought. It is a member of an ancient basal thyreophoran lineage that survived until the Late Cretaceous in South America.
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Affiliation(s)
- Facundo J Riguetti
- Fundación de Historia Natural Félix de Azara, Centro de Ciencias Naturales Ambientales y Antropológicas, Universidad Maimónides, CONICET, Hidalgo 775, 7mo piso (1405), Buenos Aires, Argentina.
| | - Sebastián Apesteguía
- Fundación de Historia Natural Félix de Azara, Centro de Ciencias Naturales Ambientales y Antropológicas, Universidad Maimónides, CONICET, Hidalgo 775, 7mo piso (1405), Buenos Aires, Argentina
| | - Xabier Pereda-Suberbiola
- Departamento de Geología, Facultad de Ciencia y Tecnología, Universidad del País Vasco/Euskal Herriko Unibertsitatea, Apartado 644, 48080, Bilbao, Spain
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Schade M, Stumpf S, Kriwet J, Kettler C, Pfaff C. Neuroanatomy of the nodosaurid Struthiosaurus austriacus (Dinosauria: Thyreophora) supports potential ecological differentiations within Ankylosauria. Sci Rep 2022; 12:144. [PMID: 34996895 PMCID: PMC8741922 DOI: 10.1038/s41598-021-03599-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2021] [Accepted: 12/06/2021] [Indexed: 11/09/2022] Open
Abstract
Nodosauridae is a group of thyreophoran dinosaurs characterized by a collar of prominent osteoderms. In comparison to its sister group, the often club-tailed ankylosaurids, a different lifestyle of nodosaurids could be assumed based on their neuroanatomy and weaponry, e.g., regarding applied defensive strategies. The holotype of the nodosaurid Struthiosaurus austriacus consists of a single partial braincase from the Late Cretaceous of Austria. Since neuroanatomy is considered to be associated with ecological tendencies, we created digital models of the braincase based on micro-CT data. The cranial endocast of S. austriacus generally resembles those of its relatives. A network of vascular canals surrounding the brain cavity further supports special thermoregulatory adaptations within Ankylosauria. The horizontal orientation of the lateral semicircular canal independently confirms previous appraisals of head posture for S. austriacus and, hence, strengthens the usage of the LSC as proxy for habitual head posture in fossil tetrapods. The short anterior and angular lateral semicircular canals, combined with the relatively shortest dinosaurian cochlear duct known so far and the lack of a floccular recess suggest a rather inert lifestyle without the necessity of sophisticated senses for equilibrium and hearing in S. austriacus. These observations agree with an animal that adapted to a comparatively inactive lifestyle with limited social interactions.
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Affiliation(s)
- Marco Schade
- Institute of Geography and Geology, Palaeontology and Historical Geology, University of Greifswald, 17489, Greifswald, Germany. .,Zoological Institute and Museum, Cytology and Evolutionary Biology, University of Greifswald, 17489, Greifswald, Germany. .,Department of Earth and Environmental Sciences, Palaeontology and Geobiology, Ludwig-Maximilians-Universität, 80333, Munich, Germany.
| | - Sebastian Stumpf
- Department of Palaeontology, Faculty of Earth Sciences, Geography and Astronomy, University of Vienna, 1090, Vienna, Austria
| | - Jürgen Kriwet
- Department of Palaeontology, Faculty of Earth Sciences, Geography and Astronomy, University of Vienna, 1090, Vienna, Austria
| | - Christoph Kettler
- Department of Geology, Faculty of Earth Sciences, Geography and Astronomy, University of Vienna, 1090, Vienna, Austria
| | - Cathrin Pfaff
- Department of Palaeontology, Faculty of Earth Sciences, Geography and Astronomy, University of Vienna, 1090, Vienna, Austria.
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