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“Forms” of water mites (Acari: Hydrachnidia): intraspecific variation or valid species?

In many groups of organisms, especially in the older literature, it has been common practice to recognize sympatrically occurring phenotypic variants of a species as “forms”. However, what these forms really represent often remains unclear, especially in poorly studied groups. With new algorithms fo...

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Autores principales: Stålstedt, Jeanette, Bergsten, Johannes, Ronquist, Fredrik
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Blackwell Publishing Ltd 2013
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3797488/
https://www.ncbi.nlm.nih.gov/pubmed/24223279
http://dx.doi.org/10.1002/ece3.704
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author Stålstedt, Jeanette
Bergsten, Johannes
Ronquist, Fredrik
author_facet Stålstedt, Jeanette
Bergsten, Johannes
Ronquist, Fredrik
author_sort Stålstedt, Jeanette
collection PubMed
description In many groups of organisms, especially in the older literature, it has been common practice to recognize sympatrically occurring phenotypic variants of a species as “forms”. However, what these forms really represent often remains unclear, especially in poorly studied groups. With new algorithms for DNA-based species delimitation, the status of forms can be explicitly tested with molecular data. In this study, we test a number of what is now recognized as valid species of water mites (Hydrachnidia), but have in the past been treated as forms sympatrically occurring with their nominate species. We also test a form without prior taxonomical status, using DNA and morphometrics. The barcoding fragment of COI, nuclear 28S and quantitative analyses of morphological data were used to test whether these taxa merit species status, as suggested by several taxonomists. Our results confirm valid species. Genetic distances between the form and nominate species (Piona dispersa and Piona variabilis, COI 11%), as well as likelihood ratio tests under the general mixed-Yule coalescent model, supported that these are separately evolving lineages as defined by the unified species concept. In addition, they can be diagnosed with morphological characters. The study also reveals that some taxa genetically represent more than one species. We propose that P. dispersa are recognized as valid taxa at the species level. Unionicola minor (which may consist of several species), Piona stjordalensis, P. imminuta s. lat., and P. rotundoides are confirmed as species using this model. The results also imply that future studies of other water mite species complexes are likely to reveal many more genetically and morphologically distinct species.
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spelling pubmed-37974882013-11-12 “Forms” of water mites (Acari: Hydrachnidia): intraspecific variation or valid species? Stålstedt, Jeanette Bergsten, Johannes Ronquist, Fredrik Ecol Evol Original Research In many groups of organisms, especially in the older literature, it has been common practice to recognize sympatrically occurring phenotypic variants of a species as “forms”. However, what these forms really represent often remains unclear, especially in poorly studied groups. With new algorithms for DNA-based species delimitation, the status of forms can be explicitly tested with molecular data. In this study, we test a number of what is now recognized as valid species of water mites (Hydrachnidia), but have in the past been treated as forms sympatrically occurring with their nominate species. We also test a form without prior taxonomical status, using DNA and morphometrics. The barcoding fragment of COI, nuclear 28S and quantitative analyses of morphological data were used to test whether these taxa merit species status, as suggested by several taxonomists. Our results confirm valid species. Genetic distances between the form and nominate species (Piona dispersa and Piona variabilis, COI 11%), as well as likelihood ratio tests under the general mixed-Yule coalescent model, supported that these are separately evolving lineages as defined by the unified species concept. In addition, they can be diagnosed with morphological characters. The study also reveals that some taxa genetically represent more than one species. We propose that P. dispersa are recognized as valid taxa at the species level. Unionicola minor (which may consist of several species), Piona stjordalensis, P. imminuta s. lat., and P. rotundoides are confirmed as species using this model. The results also imply that future studies of other water mite species complexes are likely to reveal many more genetically and morphologically distinct species. Blackwell Publishing Ltd 2013-09 2013-08-28 /pmc/articles/PMC3797488/ /pubmed/24223279 http://dx.doi.org/10.1002/ece3.704 Text en © 2013 Published by John Wiley & Sons Ltd http://creativecommons.org/licenses/by/2.5/ Re-use of this article is permitted in accordance with the Creative Commons Deed, Attribution 2.5, which does not permit commercial exploitation.
spellingShingle Original Research
Stålstedt, Jeanette
Bergsten, Johannes
Ronquist, Fredrik
“Forms” of water mites (Acari: Hydrachnidia): intraspecific variation or valid species?
title “Forms” of water mites (Acari: Hydrachnidia): intraspecific variation or valid species?
title_full “Forms” of water mites (Acari: Hydrachnidia): intraspecific variation or valid species?
title_fullStr “Forms” of water mites (Acari: Hydrachnidia): intraspecific variation or valid species?
title_full_unstemmed “Forms” of water mites (Acari: Hydrachnidia): intraspecific variation or valid species?
title_short “Forms” of water mites (Acari: Hydrachnidia): intraspecific variation or valid species?
title_sort “forms” of water mites (acari: hydrachnidia): intraspecific variation or valid species?
topic Original Research
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3797488/
https://www.ncbi.nlm.nih.gov/pubmed/24223279
http://dx.doi.org/10.1002/ece3.704
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