Assessment of the extirpated Maritimes walrus using morphological and ancient DNA analysis.

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...

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Autores principales:	Brenna A McLeod, Timothy R Frasier, Zoe Lucas
Formato:	article
Lenguaje:	EN
Publicado:	Public Library of Science (PLoS) 2014
Materias:	Medicine R Science Q
Acceso en línea:	https://doaj.org/article/24eb7b6575ac4c99b49a682e6e0d180b
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spelling	oai:doaj.org-article:24eb7b6575ac4c99b49a682e6e0d180b2021-11-18T08:15:51ZAssessment of the extirpated Maritimes walrus using morphological and ancient DNA analysis.1932-620310.1371/journal.pone.0099569https://doaj.org/article/24eb7b6575ac4c99b49a682e6e0d180b2014-01-01T00:00:00Zhttps://www.ncbi.nlm.nih.gov/pmc/articles/pmid/24924490/?tool=EBIhttps://doaj.org/toc/1932-6203Species 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.Brenna A McLeodTimothy R FrasierZoe LucasPublic Library of Science (PLoS)articleMedicineRScienceQENPLoS ONE, Vol 9, Iss 6, p e99569 (2014)
institution	DOAJ
collection	DOAJ
language	EN
topic	Medicine R Science Q
spellingShingle	Medicine R Science Q Brenna A McLeod Timothy R Frasier Zoe Lucas Assessment of the extirpated Maritimes walrus using morphological and ancient DNA analysis.
description	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	article
author	Brenna A McLeod Timothy R Frasier Zoe Lucas
author_facet	Brenna A McLeod Timothy R Frasier Zoe Lucas
author_sort	Brenna A McLeod
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 (PLoS)
publishDate	2014
url	https://doaj.org/article/24eb7b6575ac4c99b49a682e6e0d180b
work_keys_str_mv	AT brennaamcleod assessmentoftheextirpatedmaritimeswalrususingmorphologicalandancientdnaanalysis AT timothyrfrasier assessmentoftheextirpatedmaritimeswalrususingmorphologicalandancientdnaanalysis AT zoelucas assessmentoftheextirpatedmaritimeswalrususingmorphologicalandancientdnaanalysis
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Assessment of the extirpated Maritimes walrus using morphological and ancient DNA analysis.

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