Assessment of the extirpated Maritimes walrus using morphological and ancient DNA analysis
Publisher's Version/PDF Species biogeography is a result of complex events and factors associated with climate change, ecological interactions, anthropogenic impacts, physical geography, and evolution. To understand the contemporary biogeography of a species, it is necessary to understand its h...
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ftstmarysunivca:oai:library2:01/27365 2023-05-15T15:14:49+02:00 Assessment of the extirpated Maritimes walrus using morphological and ancient DNA analysis McLeod, Brenna A. Frasier, Timothy, 1976- Lucas, Zoe 2014-06-12 application/pdf http://library2.smu.ca/handle/01/27365 en eng Public Library of Science 1932-6203 http://library2.smu.ca/handle/01/27365 Creative Commons Attribution License 4.0 CC-BY Walrus -- Maritime Provinces Extinct mammals -- Maritime Provinces Biogeography -- Climatic factors -- Maritime Provinces Walrus -- Morphology Walrus -- Genetics Text 2014 ftstmarysunivca 2022-05-13T05:45:14Z Publisher's Version/PDF Species biogeography is a result of complex events and factors associated with climate change, ecological interactions, anthropogenic impacts, physical geography, and evolution. To understand the contemporary biogeography of a species, it is necessary to understand its history. Specimens from areas of localized extinction are important, as extirpation of species from these areas may represent the loss of unique adaptations and a distinctive evolutionary trajectory. The walrus (Odobenus rosmarus) has a discontinuous circumpolar distribution in the arctic and subarctic that once included the southeastern Canadian Maritimes region. However, exploitation of the Maritimes population during the 16th-18th centuries led to extirpation, and the species has not inhabited areas south of 55°N for ∼250 years. We examined genetic and morphological characteristics of specimens from the Maritimes, Atlantic (O. r. rosmarus) and Pacific (O. r. divergens) populations to test the hypothesis that the first group was distinctive. Analysis of Atlantic and Maritimes specimens indicated that most skull and mandibular measurements were significantly different between the Maritimes and Atlantic groups and discriminant analysis of principal components confirmed them as distinctive groups, with complete isolation of skull features. The Maritimes walrus appear to have been larger animals, with larger and more robust tusks, skulls and mandibles. The mtDNA control region haplotypes identified in Maritimes specimens were unique to the region and a greater average number of nucleotide differences were found between the regions (Atlantic and Maritimes) than within either group. Levels of diversity (h and π) were lower in the Maritimes, consistent with other studies of species at range margins. Our data suggest that the Maritimes walrus was a morphologically and genetically distinctive group that was on a different evolutionary path from other walrus found in the north Atlantic. Text Arctic Climate change North Atlantic Odobenus rosmarus Subarctic walrus* Saint Mary's University, Halifax: Institutional Repository Arctic Pacific |
institution |
Open Polar |
collection |
Saint Mary's University, Halifax: Institutional Repository |
op_collection_id |
ftstmarysunivca |
language |
English |
topic |
Walrus -- Maritime Provinces Extinct mammals -- Maritime Provinces Biogeography -- Climatic factors -- Maritime Provinces Walrus -- Morphology Walrus -- Genetics |
spellingShingle |
Walrus -- Maritime Provinces Extinct mammals -- Maritime Provinces Biogeography -- Climatic factors -- Maritime Provinces Walrus -- Morphology Walrus -- Genetics McLeod, Brenna A. Frasier, Timothy, 1976- Lucas, Zoe Assessment of the extirpated Maritimes walrus using morphological and ancient DNA analysis |
topic_facet |
Walrus -- Maritime Provinces Extinct mammals -- Maritime Provinces Biogeography -- Climatic factors -- Maritime Provinces Walrus -- Morphology Walrus -- Genetics |
description |
Publisher's Version/PDF Species biogeography is a result of complex events and factors associated with climate change, ecological interactions, anthropogenic impacts, physical geography, and evolution. To understand the contemporary biogeography of a species, it is necessary to understand its history. Specimens from areas of localized extinction are important, as extirpation of species from these areas may represent the loss of unique adaptations and a distinctive evolutionary trajectory. The walrus (Odobenus rosmarus) has a discontinuous circumpolar distribution in the arctic and subarctic that once included the southeastern Canadian Maritimes region. However, exploitation of the Maritimes population during the 16th-18th centuries led to extirpation, and the species has not inhabited areas south of 55°N for ∼250 years. We examined genetic and morphological characteristics of specimens from the Maritimes, Atlantic (O. r. rosmarus) and Pacific (O. r. divergens) populations to test the hypothesis that the first group was distinctive. Analysis of Atlantic and Maritimes specimens indicated that most skull and mandibular measurements were significantly different between the Maritimes and Atlantic groups and discriminant analysis of principal components confirmed them as distinctive groups, with complete isolation of skull features. The Maritimes walrus appear to have been larger animals, with larger and more robust tusks, skulls and mandibles. The mtDNA control region haplotypes identified in Maritimes specimens were unique to the region and a greater average number of nucleotide differences were found between the regions (Atlantic and Maritimes) than within either group. Levels of diversity (h and π) were lower in the Maritimes, consistent with other studies of species at range margins. Our data suggest that the Maritimes walrus was a morphologically and genetically distinctive group that was on a different evolutionary path from other walrus found in the north Atlantic. |
format |
Text |
author |
McLeod, Brenna A. Frasier, Timothy, 1976- Lucas, Zoe |
author_facet |
McLeod, Brenna A. Frasier, Timothy, 1976- Lucas, Zoe |
author_sort |
McLeod, Brenna A. |
title |
Assessment of the extirpated Maritimes walrus using morphological and ancient DNA analysis |
title_short |
Assessment of the extirpated Maritimes walrus using morphological and ancient DNA analysis |
title_full |
Assessment of the extirpated Maritimes walrus using morphological and ancient DNA analysis |
title_fullStr |
Assessment of the extirpated Maritimes walrus using morphological and ancient DNA analysis |
title_full_unstemmed |
Assessment of the extirpated Maritimes walrus using morphological and ancient DNA analysis |
title_sort |
assessment of the extirpated maritimes walrus using morphological and ancient dna analysis |
publisher |
Public Library of Science |
publishDate |
2014 |
url |
http://library2.smu.ca/handle/01/27365 |
geographic |
Arctic Pacific |
geographic_facet |
Arctic Pacific |
genre |
Arctic Climate change North Atlantic Odobenus rosmarus Subarctic walrus* |
genre_facet |
Arctic Climate change North Atlantic Odobenus rosmarus Subarctic walrus* |
op_relation |
1932-6203 http://library2.smu.ca/handle/01/27365 |
op_rights |
Creative Commons Attribution License 4.0 |
op_rightsnorm |
CC-BY |
_version_ |
1766345219895197696 |