Morphometric analysis of equid cheek teeth using a digital image processor: a case study of the Pleistocene Cedazo local fauna equids, Mexico
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| Format: | Artículo científico |
| Sprache: | en |
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Universidad Nacional Autónoma de México
2008
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| _version_ | 1876462544915267584 |
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| author | Christian Raúl Barrón-Ortiz |
| author_facet | Christian Raúl Barrón-Ortiz |
| contents | Morphometric analysis of equid cheek teeth using a digital image processor: a case study of the Pleistocene Cedazo local fauna equids, Mexico Christian Raúl Barrón-Ortiz Gilfredo de la Riva-Hernández Raúl Barrón-Corvera Ciencias de la Tierra equids Mexico Pleistocene Morphometrics Cedazo local fauna The occlusal pattern of the cheek teeth has traditionally been one of the most widely used features to determinate equid species. Nevertheless, its large ontogenetic variation and subjective assessment of characters has diminished its reliability. For this reason, many workers have reduced emphasis on the cheek teeth in identifying equid species and have turned their attention to other skeletal elements. We re-emphasize the analysis of the oclusal pattern to determine the number of equid species present in the Cedazo local fauna, Aguascalientes, Mexico. In contrast to previous studies, we only analyzed cheek teeth with an equivalent stage of wear and developed a computer program that integrates a digital image processor to analyze the occlusal pattern and also to take measurements of different features of the occlusal surface. Selecting teeth with an equivalent stage of wear reduced the usable sample size signi fi cantly. For this reason, the analysis concentrated on the third upper premolars (P 3 ), because they represent the largest sample size. Specimens of Equus caballus, E. asinus and hybrids were also included to serve as controls. Principal Components and Canonical Discriminant Functions analyses were performed. The extant species were positively discriminated. Moreover, these analyses suggest the presence of two distinct P 3 morphotypes for the fossil sample studied, which indicate the possible occurrence of at least two separate equid species for the Cedazo local fauna. However, it is prudent to collect more material and evaluate these results with a larger sample size and using the remaining tooth positions. The computer program developed in this study serves as a useful tool for analyzing the occlusal pattern of equid cheek teeth. 2008 artículo científico 1026-8774 https://www.redalyc.org/articulo.oa?id=57230346010 en http://www.redalyc.org/revista.oa?id=572 Revista Mexicana de Ciencias Geológicas application/pdf Universidad Nacional Autónoma de México Revista Mexicana de Ciencias Geológicas (México) Num.2 Vol.25 |
| format | Artículo científico |
| id | redalyc_57230346010 |
| institution | Redalyc |
| language | en |
| publishDate | 2008 |
| publisher | Universidad Nacional Autónoma de México |
| spellingShingle | Morphometric analysis of equid cheek teeth using a digital image processor: a case study of the Pleistocene Cedazo local fauna equids, Mexico Christian Raúl Barrón-Ortiz Ciencias de la Tierra equids Mexico Pleistocene Morphometrics Cedazo local fauna Morphometric analysis of equid cheek teeth using a digital image processor: a case study of the Pleistocene Cedazo local fauna equids, Mexico Christian Raúl Barrón-Ortiz Gilfredo de la Riva-Hernández Raúl Barrón-Corvera Ciencias de la Tierra equids Mexico Pleistocene Morphometrics Cedazo local fauna The occlusal pattern of the cheek teeth has traditionally been one of the most widely used features to determinate equid species. Nevertheless, its large ontogenetic variation and subjective assessment of characters has diminished its reliability. For this reason, many workers have reduced emphasis on the cheek teeth in identifying equid species and have turned their attention to other skeletal elements. We re-emphasize the analysis of the oclusal pattern to determine the number of equid species present in the Cedazo local fauna, Aguascalientes, Mexico. In contrast to previous studies, we only analyzed cheek teeth with an equivalent stage of wear and developed a computer program that integrates a digital image processor to analyze the occlusal pattern and also to take measurements of different features of the occlusal surface. Selecting teeth with an equivalent stage of wear reduced the usable sample size signi fi cantly. For this reason, the analysis concentrated on the third upper premolars (P 3 ), because they represent the largest sample size. Specimens of Equus caballus, E. asinus and hybrids were also included to serve as controls. Principal Components and Canonical Discriminant Functions analyses were performed. The extant species were positively discriminated. Moreover, these analyses suggest the presence of two distinct P 3 morphotypes for the fossil sample studied, which indicate the possible occurrence of at least two separate equid species for the Cedazo local fauna. However, it is prudent to collect more material and evaluate these results with a larger sample size and using the remaining tooth positions. The computer program developed in this study serves as a useful tool for analyzing the occlusal pattern of equid cheek teeth. 2008 artículo científico 1026-8774 https://www.redalyc.org/articulo.oa?id=57230346010 en http://www.redalyc.org/revista.oa?id=572 Revista Mexicana de Ciencias Geológicas application/pdf Universidad Nacional Autónoma de México Revista Mexicana de Ciencias Geológicas (México) Num.2 Vol.25 |
| title | Morphometric analysis of equid cheek teeth using a digital image processor: a case study of the Pleistocene Cedazo local fauna equids, Mexico |
| topic | Ciencias de la Tierra equids Mexico Pleistocene Morphometrics Cedazo local fauna |
| url | https://www.redalyc.org/articulo.oa?id=57230346010 |