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Astragalar Morphology of Selected Giraffidae.

Solounias N, Danowitz M - PLoS ONE (2016)

Bottom Line: The giraffid astragalar morphologies reinforce previously established phylogenetic relationships.The sivatheres and the okapi share a reduced notch on the lateral edge of the astragalus.We find that Samotherium is more primitive in astragalar morphologies than Palaeotragus, which is reinforced by tooth characteristics and ossicone position.

View Article: PubMed Central - PubMed

Affiliation: Department of Anatomy, New York Institute of Technology College of Osteopathic Medicine, Old Westbury, NY, United States of America.

ABSTRACT
The artiodactyl astragalus has been modified to exhibit two trochleae, creating a double pullied structure allowing for significant dorso-plantar motion, and limited mediolateral motion. The astragalus structure is partly influenced by environmental substrates, and correspondingly, morphometric studies can yield paleohabitat information. The present study establishes terminology and describes detailed morphological features on giraffid astragali. Each giraffid astragalus exhibits a unique combination of anatomical characteristics. The giraffid astragalar morphologies reinforce previously established phylogenetic relationships. We find that the enlargement of the navicular head is a feature shared by all giraffids, and that the primitive giraffids possess exceptionally tall astragalar heads in relation to the total astragalar height. The sivatheres and the okapi share a reduced notch on the lateral edge of the astragalus. We find that Samotherium is more primitive in astragalar morphologies than Palaeotragus, which is reinforced by tooth characteristics and ossicone position. Diagnostic anatomical characters on the astragalus allow for giraffid species identifications and a better understanding of Giraffidae.

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Astragalar terminology.(A) Photograph of a Samotherium major (GMM 2002) astragalus in dorsal view, with representative terminology. (B) Samotherium major (GMM 2002) astragalus in ventral view, with representative terminology. The scale bar represents 50 mm.
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pone.0151310.g001: Astragalar terminology.(A) Photograph of a Samotherium major (GMM 2002) astragalus in dorsal view, with representative terminology. (B) Samotherium major (GMM 2002) astragalus in ventral view, with representative terminology. The scale bar represents 50 mm.

Mentions: We identify the astragali of 12 giraffid species and Prodremotherium (Table 1). Identifications were based on known species identifications at each locality, as well as size differences between the taxa. We establish terminology (Fig 1), and describe the detailed morphological features of the astragalus of Samotherium major, because it is a representative giraffid species that exhibits a mosaic of primitive and specialized features. Subsequently, we compare each taxon against S. major. The astragalar specimens utilized for the descriptions were chosen from the type locality where each species was named. We measure the medial length, lateral length, and distal width using standard calipers in millimeters (Table 2). The astragali utilized for morphological descriptions and measurements are housed in the American Museum of Natural History, New York (AMNH), Geomuseum of the WWU, Münster (GMM), Geological Museum of Lausanne (MGL), Muséum National d’Histoire Naturelle, Paris (MNHN), Natural History Museum, Bern (NHM Be), Natural History Museum, London (NHM UK), Pakistan Natural History Museum, Islamabad (PMNH), Palaeontological Institute of Uppsala (PIU), University of Bristol (UB), University of California, Berkeley (UCB). All specimens were collected legally and have been housed in established natural history museums. All specimens are accessible to visiting scientists with permission from the curators.


Astragalar Morphology of Selected Giraffidae.

Solounias N, Danowitz M - PLoS ONE (2016)

Astragalar terminology.(A) Photograph of a Samotherium major (GMM 2002) astragalus in dorsal view, with representative terminology. (B) Samotherium major (GMM 2002) astragalus in ventral view, with representative terminology. The scale bar represents 50 mm.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4814102&req=5

pone.0151310.g001: Astragalar terminology.(A) Photograph of a Samotherium major (GMM 2002) astragalus in dorsal view, with representative terminology. (B) Samotherium major (GMM 2002) astragalus in ventral view, with representative terminology. The scale bar represents 50 mm.
Mentions: We identify the astragali of 12 giraffid species and Prodremotherium (Table 1). Identifications were based on known species identifications at each locality, as well as size differences between the taxa. We establish terminology (Fig 1), and describe the detailed morphological features of the astragalus of Samotherium major, because it is a representative giraffid species that exhibits a mosaic of primitive and specialized features. Subsequently, we compare each taxon against S. major. The astragalar specimens utilized for the descriptions were chosen from the type locality where each species was named. We measure the medial length, lateral length, and distal width using standard calipers in millimeters (Table 2). The astragali utilized for morphological descriptions and measurements are housed in the American Museum of Natural History, New York (AMNH), Geomuseum of the WWU, Münster (GMM), Geological Museum of Lausanne (MGL), Muséum National d’Histoire Naturelle, Paris (MNHN), Natural History Museum, Bern (NHM Be), Natural History Museum, London (NHM UK), Pakistan Natural History Museum, Islamabad (PMNH), Palaeontological Institute of Uppsala (PIU), University of Bristol (UB), University of California, Berkeley (UCB). All specimens were collected legally and have been housed in established natural history museums. All specimens are accessible to visiting scientists with permission from the curators.

Bottom Line: The giraffid astragalar morphologies reinforce previously established phylogenetic relationships.The sivatheres and the okapi share a reduced notch on the lateral edge of the astragalus.We find that Samotherium is more primitive in astragalar morphologies than Palaeotragus, which is reinforced by tooth characteristics and ossicone position.

View Article: PubMed Central - PubMed

Affiliation: Department of Anatomy, New York Institute of Technology College of Osteopathic Medicine, Old Westbury, NY, United States of America.

ABSTRACT
The artiodactyl astragalus has been modified to exhibit two trochleae, creating a double pullied structure allowing for significant dorso-plantar motion, and limited mediolateral motion. The astragalus structure is partly influenced by environmental substrates, and correspondingly, morphometric studies can yield paleohabitat information. The present study establishes terminology and describes detailed morphological features on giraffid astragali. Each giraffid astragalus exhibits a unique combination of anatomical characteristics. The giraffid astragalar morphologies reinforce previously established phylogenetic relationships. We find that the enlargement of the navicular head is a feature shared by all giraffids, and that the primitive giraffids possess exceptionally tall astragalar heads in relation to the total astragalar height. The sivatheres and the okapi share a reduced notch on the lateral edge of the astragalus. We find that Samotherium is more primitive in astragalar morphologies than Palaeotragus, which is reinforced by tooth characteristics and ossicone position. Diagnostic anatomical characters on the astragalus allow for giraffid species identifications and a better understanding of Giraffidae.

Show MeSH
Related in: MedlinePlus