Hindlimb and pelvic anatomy of Caiman yacare (Archosauria, Pseudosuchia): Myology and osteological correlates with emphasis on lower leg and autopodial musculature

• Autores: Pereyra, María Eugenia; Cerroni, Mauricio; Lecuona, Agustina; Bona, Paula; Fernández Dumont, Lucila; Otero, Alejandro
• Año de publicación: 2023
• Idioma: inglés
• Tipo de recurso: artículo
• Materia: Ciencias Exactas y Naturales; autopodium; crocodylian; mm; extensores digiti brevis profundus; muscles; Ciencias Exactas y Naturales
• Institución: Universidad Nacional de Río Negro

Fil: Pereyra, María Eugenia. Consejo Nacional de Investigaciones Científicas y Técnicas-CONICET. División Paleontología Vertebrados, Anexo Laboratorios, Facultad de Ciencias Naturales y Museo. Department of Biological Sciences, University of Cape Town. Argentina.
Fil: Cerroni, Mauricio. Consejo Nacional de Investigaciones Científicas y Técnicas-CONICET. Laboratorio de Anatomía Comparada y Evolución de los Vertebrados, Museo Argentino de Ciencias Naturales ‘Bernardino Rivadavia’. Argentina.
Fil: Lecuona, Agustina. Instituto de Investigación en Paleobiología y Geología (IIPG, CONICET-UNRN). Universidad Nacional de Río Negro, Instituto de Investigación en Paleobiología y Geología. Argentina.
Fil: Bona, Paula. Consejo Nacional de Investigaciones Científicas y Técnicas-CONICET. División Paleontología Vertebrados, Anexo Laboratorios, Facultad de Ciencias Naturales y Museo. Argentina.
Fil: Fernández Dumont, Lucila. Consejo Nacional de Investigaciones Científicas y Técnicas-CONICET. Fundación de Historia Natural Félix de Azara, Centro de Ciencias Naturales Ambientales y Antropológicas, Universidad Maimónides. Argentina.
Fil: Otero, Alejandro. Consejo Nacional de Investigaciones Científicas y Técnicas-CONICET. División Paleontología Vertebrados, Anexo Laboratorios, Facultad de Ciencias Naturales y Museo. Argentina.
The anatomy of the archosaurian pelvis and hindlimb has adopted a diversity of successful configurations allowing a wide range of postures during the evolution of the group (e.g., erect, sprawling). For this reason, thorough studies of the structure and function of the pelvic and hindlimb musculature of crocodylians are required and provide the possibility to expand their implications for the evolution of archosaurian locomotion, as well as to identify potential new characters based on muscles and their bony correlates. In this study, we give a detailed description of the pelvic and hindlimb musculature of the South American alligator Caiman yacare, providing comprehensive novel information regarding lower limb and autopodial muscles. Particularly for the pedal muscles, we propose a new classification for the dorsal and ventral muscles of the autopodium based on the organisation of these muscles in successive layers. We have studied the myology in a global background in which we have compared the Caiman yacare musculature with other crocodylians. In this sense, differences in the arrangement of m. flexor tibialis internus 1, m. flexor tibialis externus, m. iliofibularis, mm. puboischiofemorales internii 1 and 2, between Ca. yacare and other crocodylians were found. We also discuss the muscle attachments that have different bony correlates among the crocodylian species and their morphological variation. Most of the correlates did not exhibit great variation among the species compared. The majority of the recognised correlates were identified in the pelvic girdle; additionally, some bony correlates associated with the pedal muscles are highlighted here for the first time. This research provides a wide framework for future studies on comparative anatomy and functional morphology, which could contribute to improving the character definition used in phylogenetic analyses and to understand the patterns of musculoskeletal hindlimb evolution.
The anatomy of the archosaurian pelvis and hindlimb has adopted a diversity of successful configurations allowing a wide range of postures during the evolution of the group (e.g., erect, sprawling). For this reason, thorough studies of the structure and function of the pelvic and hindlimb musculature of crocodylians are required and provide the possibility to expand their implications for the evolution of archosaurian locomotion, as well as to identify potential new characters based on muscles and their bony correlates. In this study, we give a detailed description of the pelvic and hindlimb musculature of the South American alligator Caiman yacare, providing comprehensive novel information regarding lower limb and autopodial muscles. Particularly for the pedal muscles, we propose a new classification for the dorsal and ventral muscles of the autopodium based on the organisation of these muscles in successive layers. We have studied the myology in a global background in which we have compared the Caiman yacare musculature with other crocodylians. In this sense, differences in the arrangement of m. flexor tibialis internus 1, m. flexor tibialis externus, m. iliofibularis, mm. puboischiofemorales internii 1 and 2, between Ca. yacare and other crocodylians were found. We also discuss the muscle attachments that have different bony correlates among the crocodylian species and their morphological variation. Most of the correlates did not exhibit great variation among the species compared. The majority of the recognised correlates were identified in the pelvic girdle; additionally, some bony correlates associated with the pedal muscles are highlighted here for the first time. This research provides a wide framework for future studies on comparative anatomy and functional morphology, which could contribute to improving the character definition used in phylogenetic analyses and to understand the patterns of musculoskeletal hindlimb evolution.