albertonykus
Well-known member
Jadwiszczak, P., A. Svensson-Marcial, and T. Mörs (2022)
An integrative insight into the synsacral canal of fossil and extant Antarctic penguins
Integrative Zoology (advance online publication)
doi: 10.1111/1749-4877.12689
The lumbosacral-canal system in birds most likely operates as a sense organ involved in the control of balanced walking and perching, but our knowledge of it is superficial. Penguins constitute interesting objects for the study of this system due to their upright walking, but only the Humboldt penguin, Spheniscus humboldti Meyen, 1834, and some incomplete fossil penguin synsacra have been studied in this respect. Here we give an integrative comparative insight into the synsacral canal of extant Emperor penguin, Aptenodytes forsteri G.R. Gray, 1844, Adelie penguin, Pygoscelis adeliae, (Hombron et Jacquinot, 1841), and Eocene giant Anthropornis Wiman, 1905 and/or Palaeeudyptes Huxley, 1859 Antarctic penguins, using computed tomography imaging and associated data-extraction methodologies, complemented by analytical approaches ranging from geometric morphometrics to modularity, curvature and wavelet analyses. We document that the variability in the number of synsacro-lumbar vertebrae is evolutionarily conserved, and all studied synsacra possess osteological correlates of the lumbosacral-canal system. We also found that Eocene and extant Antarctic penguins were separable on the basis of the main direction of the shape-related (size-independent) variability within said system, and A. forsteri was unique in the entire studied set in terms of the relative cranial shift of this compound structure. Moreover, we suggest that the evolutionary processes, shaping both the terrestrial posture and gait, were responsible for the increased, in extant penguins, simplicity and stability of the synsacral canal cross-sectional periodic patterns as well as pave the way for the lumbosacral-canal system modularity characterized by reduced atomization/complexity.
An integrative insight into the synsacral canal of fossil and extant Antarctic penguins
Integrative Zoology (advance online publication)
doi: 10.1111/1749-4877.12689
The lumbosacral-canal system in birds most likely operates as a sense organ involved in the control of balanced walking and perching, but our knowledge of it is superficial. Penguins constitute interesting objects for the study of this system due to their upright walking, but only the Humboldt penguin, Spheniscus humboldti Meyen, 1834, and some incomplete fossil penguin synsacra have been studied in this respect. Here we give an integrative comparative insight into the synsacral canal of extant Emperor penguin, Aptenodytes forsteri G.R. Gray, 1844, Adelie penguin, Pygoscelis adeliae, (Hombron et Jacquinot, 1841), and Eocene giant Anthropornis Wiman, 1905 and/or Palaeeudyptes Huxley, 1859 Antarctic penguins, using computed tomography imaging and associated data-extraction methodologies, complemented by analytical approaches ranging from geometric morphometrics to modularity, curvature and wavelet analyses. We document that the variability in the number of synsacro-lumbar vertebrae is evolutionarily conserved, and all studied synsacra possess osteological correlates of the lumbosacral-canal system. We also found that Eocene and extant Antarctic penguins were separable on the basis of the main direction of the shape-related (size-independent) variability within said system, and A. forsteri was unique in the entire studied set in terms of the relative cranial shift of this compound structure. Moreover, we suggest that the evolutionary processes, shaping both the terrestrial posture and gait, were responsible for the increased, in extant penguins, simplicity and stability of the synsacral canal cross-sectional periodic patterns as well as pave the way for the lumbosacral-canal system modularity characterized by reduced atomization/complexity.
