Forelimb anatomy in basal archosaurs: functional implications

Basal archosaurs show profound apendicular transformations when compared to their closest archosauriform outgroup (Euparkeria or proterochampsids). Although, most studies on archosaurian apendicular anatomy were focused on hindlimb morphology. The objective of this contribution was to study morpholo...

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Autor principal: Leardi, J. M
Formato: Objeto de conferencia Resumen
Lenguaje:Inglés
Publicado: 2010
Materias:
Ciencias Naturales
Paleontología
Acceso en línea:http://sedici.unlp.edu.ar/handle/10915/16897
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SEDICI (UNLP) de Universidad Nacional de La Plata
id I19-R120-10915-16897
record_format dspace
spelling I19-R120-10915-168972023-10-11T20:02:25Z http://sedici.unlp.edu.ar/handle/10915/16897 Forelimb anatomy in basal archosaurs: functional implications Leardi, J. M 2010 2010 2011-04-13T03:00:00Z en Ciencias Naturales Paleontología Basal archosaurs show profound apendicular transformations when compared to their closest archosauriform outgroup (Euparkeria or proterochampsids). Although, most studies on archosaurian apendicular anatomy were focused on hindlimb morphology. The objective of this contribution was to study morphological changes in the forelimb of basal archosaurs and to assess their phylogenetical and functional implications. The pectoral girdle shows an anteriorly expanded acromion process on the scapula, expanding the area of origin of part of the glenohumeral stabilizator musculature of the scapula (Mm. deltoideus clavicularis and coracobrachialis brevis dorsalis), and the presence of a postglenoid process on the coracoid, changing the orientation of the retractor musculature (M. costocoracoideus) to the sagittal plane. In the forelimb, an individualized and distally displaced medial tuberosity on the humerus, a condition present in the Crurotarsi but shared with the proterochampsids, and an ossified olecranon process on the ulna can be also observed. These characters can be interpreted as potential adaptations for erect forelimbs, as the olecranon is the insertion of the main forearm extensor (Mm. triceps brachii) and the scapulocoracoid-humerus articulation is further stabilized, allowing the limbs to move mainly on a parasagital plane. These are one of the first results that recover valuable postural information from the forelimb in this important group of diapsids. Therefore, most of these characters are relevant for the phylogeny of this group as most of them can be optimized as unambiguous synapomorphies of Archosauria. Sesiones libres Facultad de Ciencias Naturales y Museo Objeto de conferencia Resumen http://creativecommons.org/licenses/by-nc-sa/4.0/ Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International (CC BY-NC-SA 4.0) application/pdf
institution Universidad Nacional de La Plata
institution_str I-19
repository_str R-120
collection SEDICI (UNLP)
language Inglés
topic Ciencias Naturales
Paleontología
spellingShingle Ciencias Naturales
Paleontología
Leardi, J. M
Forelimb anatomy in basal archosaurs: functional implications
topic_facet Ciencias Naturales
Paleontología
description Basal archosaurs show profound apendicular transformations when compared to their closest archosauriform outgroup (Euparkeria or proterochampsids). Although, most studies on archosaurian apendicular anatomy were focused on hindlimb morphology. The objective of this contribution was to study morphological changes in the forelimb of basal archosaurs and to assess their phylogenetical and functional implications. The pectoral girdle shows an anteriorly expanded acromion process on the scapula, expanding the area of origin of part of the glenohumeral stabilizator musculature of the scapula (Mm. deltoideus clavicularis and coracobrachialis brevis dorsalis), and the presence of a postglenoid process on the coracoid, changing the orientation of the retractor musculature (M. costocoracoideus) to the sagittal plane. In the forelimb, an individualized and distally displaced medial tuberosity on the humerus, a condition present in the Crurotarsi but shared with the proterochampsids, and an ossified olecranon process on the ulna can be also observed. These characters can be interpreted as potential adaptations for erect forelimbs, as the olecranon is the insertion of the main forearm extensor (Mm. triceps brachii) and the scapulocoracoid-humerus articulation is further stabilized, allowing the limbs to move mainly on a parasagital plane. These are one of the first results that recover valuable postural information from the forelimb in this important group of diapsids. Therefore, most of these characters are relevant for the phylogeny of this group as most of them can be optimized as unambiguous synapomorphies of Archosauria.
format Objeto de conferencia
Resumen
author Leardi, J. M
author_facet Leardi, J. M
author_sort Leardi, J. M
title Forelimb anatomy in basal archosaurs: functional implications
title_short Forelimb anatomy in basal archosaurs: functional implications
title_full Forelimb anatomy in basal archosaurs: functional implications
title_fullStr Forelimb anatomy in basal archosaurs: functional implications
title_full_unstemmed Forelimb anatomy in basal archosaurs: functional implications
title_sort forelimb anatomy in basal archosaurs: functional implications
publishDate 2010
url http://sedici.unlp.edu.ar/handle/10915/16897
work_keys_str_mv AT leardijm forelimbanatomyinbasalarchosaursfunctionalimplications
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