Machine-learning strategies for testing patterns of morphological variation in small samples: sexual dimorphism in gray wolf (Canis lupus) crania
Abstract Background Studies of mammalian sexual dimorphism have traditionally involved the measurement of selected dimensions of particular skeletal elements and use of single data-analysis procedures. Consequently, such studies have been limited by a variety of both practical and conceptual constra...
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ftdoajarticles:oai:doaj.org/article:f688bdd434744394891b125502a69fed 2023-05-15T15:50:05+02:00 Machine-learning strategies for testing patterns of morphological variation in small samples: sexual dimorphism in gray wolf (Canis lupus) crania Norman MacLeod Liora Kolska Horwitz 2020-09-01T00:00:00Z https://doi.org/10.1186/s12915-020-00832-1 https://doaj.org/article/f688bdd434744394891b125502a69fed EN eng BMC http://link.springer.com/article/10.1186/s12915-020-00832-1 https://doaj.org/toc/1741-7007 doi:10.1186/s12915-020-00832-1 1741-7007 https://doaj.org/article/f688bdd434744394891b125502a69fed BMC Biology, Vol 18, Iss 1, Pp 1-26 (2020) Carnivores Morphometrics Machine learning Automated identification Convolution neural networks Ecomorphology Biology (General) QH301-705.5 article 2020 ftdoajarticles https://doi.org/10.1186/s12915-020-00832-1 2022-12-31T14:57:01Z Abstract Background Studies of mammalian sexual dimorphism have traditionally involved the measurement of selected dimensions of particular skeletal elements and use of single data-analysis procedures. Consequently, such studies have been limited by a variety of both practical and conceptual constraints. To compare and contrast what might be gained from a more exploratory, multifactorial approach to the quantitative assessment of form-variation, images of a small sample of modern Israeli gray wolf (Canis lupus) crania were analyzed via elliptical Fourier analysis of cranial outlines, a Naïve Bayes machine-learning approach to the analysis of these same outline data, and a deep-learning analysis of whole images in which all aspects of these cranial morphologies were represented. The statistical significance and stability of each discriminant result were tested using bootstrap and jackknife procedures. Results Our results reveal no evidence for statistically significant sexual size dimorphism, but significant sex-mediated shape dimorphism. These are consistent with the findings of prior wolf sexual dimorphism studies and extend these studies by identifying new aspects of dimorphic variation. Additionally, our results suggest that shape-based sexual dimorphism in the C. lupus cranial complex may be more widespread morphologically than had been appreciated by previous researchers. Conclusion Our results suggest that size and shape dimorphism can be detected in small samples and may be dissociated in mammalian morphologies. This result is particularly noteworthy in that it implies there may be a need to refine allometric hypothesis tests that seek to account for phenotypic sexual dimorphism. The methods we employed in this investigation are fully generalizable and can be applied to a wide range of biological materials and could facilitate the rapid evaluation of a diverse array of morphological/phenomic hypotheses. Article in Journal/Newspaper Canis lupus gray wolf Directory of Open Access Journals: DOAJ Articles BMC Biology 18 1 |
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Open Polar |
collection |
Directory of Open Access Journals: DOAJ Articles |
op_collection_id |
ftdoajarticles |
language |
English |
topic |
Carnivores Morphometrics Machine learning Automated identification Convolution neural networks Ecomorphology Biology (General) QH301-705.5 |
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Carnivores Morphometrics Machine learning Automated identification Convolution neural networks Ecomorphology Biology (General) QH301-705.5 Norman MacLeod Liora Kolska Horwitz Machine-learning strategies for testing patterns of morphological variation in small samples: sexual dimorphism in gray wolf (Canis lupus) crania |
topic_facet |
Carnivores Morphometrics Machine learning Automated identification Convolution neural networks Ecomorphology Biology (General) QH301-705.5 |
description |
Abstract Background Studies of mammalian sexual dimorphism have traditionally involved the measurement of selected dimensions of particular skeletal elements and use of single data-analysis procedures. Consequently, such studies have been limited by a variety of both practical and conceptual constraints. To compare and contrast what might be gained from a more exploratory, multifactorial approach to the quantitative assessment of form-variation, images of a small sample of modern Israeli gray wolf (Canis lupus) crania were analyzed via elliptical Fourier analysis of cranial outlines, a Naïve Bayes machine-learning approach to the analysis of these same outline data, and a deep-learning analysis of whole images in which all aspects of these cranial morphologies were represented. The statistical significance and stability of each discriminant result were tested using bootstrap and jackknife procedures. Results Our results reveal no evidence for statistically significant sexual size dimorphism, but significant sex-mediated shape dimorphism. These are consistent with the findings of prior wolf sexual dimorphism studies and extend these studies by identifying new aspects of dimorphic variation. Additionally, our results suggest that shape-based sexual dimorphism in the C. lupus cranial complex may be more widespread morphologically than had been appreciated by previous researchers. Conclusion Our results suggest that size and shape dimorphism can be detected in small samples and may be dissociated in mammalian morphologies. This result is particularly noteworthy in that it implies there may be a need to refine allometric hypothesis tests that seek to account for phenotypic sexual dimorphism. The methods we employed in this investigation are fully generalizable and can be applied to a wide range of biological materials and could facilitate the rapid evaluation of a diverse array of morphological/phenomic hypotheses. |
format |
Article in Journal/Newspaper |
author |
Norman MacLeod Liora Kolska Horwitz |
author_facet |
Norman MacLeod Liora Kolska Horwitz |
author_sort |
Norman MacLeod |
title |
Machine-learning strategies for testing patterns of morphological variation in small samples: sexual dimorphism in gray wolf (Canis lupus) crania |
title_short |
Machine-learning strategies for testing patterns of morphological variation in small samples: sexual dimorphism in gray wolf (Canis lupus) crania |
title_full |
Machine-learning strategies for testing patterns of morphological variation in small samples: sexual dimorphism in gray wolf (Canis lupus) crania |
title_fullStr |
Machine-learning strategies for testing patterns of morphological variation in small samples: sexual dimorphism in gray wolf (Canis lupus) crania |
title_full_unstemmed |
Machine-learning strategies for testing patterns of morphological variation in small samples: sexual dimorphism in gray wolf (Canis lupus) crania |
title_sort |
machine-learning strategies for testing patterns of morphological variation in small samples: sexual dimorphism in gray wolf (canis lupus) crania |
publisher |
BMC |
publishDate |
2020 |
url |
https://doi.org/10.1186/s12915-020-00832-1 https://doaj.org/article/f688bdd434744394891b125502a69fed |
genre |
Canis lupus gray wolf |
genre_facet |
Canis lupus gray wolf |
op_source |
BMC Biology, Vol 18, Iss 1, Pp 1-26 (2020) |
op_relation |
http://link.springer.com/article/10.1186/s12915-020-00832-1 https://doaj.org/toc/1741-7007 doi:10.1186/s12915-020-00832-1 1741-7007 https://doaj.org/article/f688bdd434744394891b125502a69fed |
op_doi |
https://doi.org/10.1186/s12915-020-00832-1 |
container_title |
BMC Biology |
container_volume |
18 |
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1 |
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1766385074287149056 |