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Changing Names with Changed Address: Integrated Taxonomy and Species Delimitation in the Holarctic Colymbetes paykulli Group (Coleoptera: Dytiscidae).

Drotz MK, Brodin T, Nilsson AN - PLoS ONE (2015)

Bottom Line: Only a few sampled specimens occur from this particular area and they are mostly found in museum and private collections.However, significant difference in size and reticulation patterns from the two regions is shown.The combined conclusion is that the C. dahuricus complex needs a more thorough investigation to fully disentangle its taxonomic status.

View Article: PubMed Central - PubMed

Affiliation: Lake Vänern Museum of Natural and Cultural History, Lidköping, Västra Götaland, Sweden.

ABSTRACT
Species delimitation of geographically isolated forms is a long-standing problem in less studied insect groups. Often taxonomic decisions are based directly on morphologic variation, and lack a discussion regarding sample size and the efficiency of migration barriers or dispersal/migration capacity of the studied species. These problems are here exemplified in a water beetle complex from the Bering Sea region that separates North America from Eurasia. Only a few sampled specimens occur from this particular area and they are mostly found in museum and private collections. Here we utilize the theory of integrated taxonomy to discuss the speciation of the Holarctic Colymbetes paykulli water beetle complex, which historically has included up to five species of which today only two are recognized. Three delimitation methods are used; landmark based morphometry of body shape, variation in reticulation patterns of the pronotum exo-skeleton and sequence variation of the partial mitochondrial gene Cyt b. Our conclusion is that the Palearctic and Nearctic populations of C. paykulli are given the status of separate species, based on the fact that all methods showed significant separation between populations. As a consequence the name of the Palearctic species is C. paykulli Erichson and the Nearctic species should be known as C. longulus LeConte. There is no clear support for delineation between Palearctic and Nearctic populations of C. dahuricus based on mtDNA. However, significant difference in size and reticulation patterns from the two regions is shown. The combined conclusion is that the C. dahuricus complex needs a more thorough investigation to fully disentangle its taxonomic status. Therefore it is here still regarded as a Holarctic species. This study highlights the importance to study several diagnosable characters that has the potential to discriminate evolutionary lineage during speciation.

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Distribution map of reported observations of the Holarctic (Δ) Colymbetes dahuricus, the Palearctic (●) C. paykulli and the Nearctic (■) C. paykulli.The latter is within this study accepted as a valid species. This means that the name of the Palearctic species is C. paykulli Erichson and the Nearctic species should be known as C. longulus LeConte.
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pone.0143577.g001: Distribution map of reported observations of the Holarctic (Δ) Colymbetes dahuricus, the Palearctic (●) C. paykulli and the Nearctic (■) C. paykulli.The latter is within this study accepted as a valid species. This means that the name of the Palearctic species is C. paykulli Erichson and the Nearctic species should be known as C. longulus LeConte.

Mentions: The dahuricus-complex: Penis apex rounded and pronotum dark rufous with transverse black discal spot. Geographical variation is seen in penis length, with Palearctic males having longer penis with apex relatively smaller [42] and in the secondary sculpture on pronotum with meshes more transversely stretched in Nearctic specimens [17]. This complex is distributed trans-continentally in North America from Alaska to Labrador with most records from western Canada. It is considered absent from the rest of the USA [17]. In the Palearctic region it occurs mainly east of the Yenisey River with the westernmost records in Altai (Fig 1).


Changing Names with Changed Address: Integrated Taxonomy and Species Delimitation in the Holarctic Colymbetes paykulli Group (Coleoptera: Dytiscidae).

Drotz MK, Brodin T, Nilsson AN - PLoS ONE (2015)

Distribution map of reported observations of the Holarctic (Δ) Colymbetes dahuricus, the Palearctic (●) C. paykulli and the Nearctic (■) C. paykulli.The latter is within this study accepted as a valid species. This means that the name of the Palearctic species is C. paykulli Erichson and the Nearctic species should be known as C. longulus LeConte.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4664258&req=5

pone.0143577.g001: Distribution map of reported observations of the Holarctic (Δ) Colymbetes dahuricus, the Palearctic (●) C. paykulli and the Nearctic (■) C. paykulli.The latter is within this study accepted as a valid species. This means that the name of the Palearctic species is C. paykulli Erichson and the Nearctic species should be known as C. longulus LeConte.
Mentions: The dahuricus-complex: Penis apex rounded and pronotum dark rufous with transverse black discal spot. Geographical variation is seen in penis length, with Palearctic males having longer penis with apex relatively smaller [42] and in the secondary sculpture on pronotum with meshes more transversely stretched in Nearctic specimens [17]. This complex is distributed trans-continentally in North America from Alaska to Labrador with most records from western Canada. It is considered absent from the rest of the USA [17]. In the Palearctic region it occurs mainly east of the Yenisey River with the westernmost records in Altai (Fig 1).

Bottom Line: Only a few sampled specimens occur from this particular area and they are mostly found in museum and private collections.However, significant difference in size and reticulation patterns from the two regions is shown.The combined conclusion is that the C. dahuricus complex needs a more thorough investigation to fully disentangle its taxonomic status.

View Article: PubMed Central - PubMed

Affiliation: Lake Vänern Museum of Natural and Cultural History, Lidköping, Västra Götaland, Sweden.

ABSTRACT
Species delimitation of geographically isolated forms is a long-standing problem in less studied insect groups. Often taxonomic decisions are based directly on morphologic variation, and lack a discussion regarding sample size and the efficiency of migration barriers or dispersal/migration capacity of the studied species. These problems are here exemplified in a water beetle complex from the Bering Sea region that separates North America from Eurasia. Only a few sampled specimens occur from this particular area and they are mostly found in museum and private collections. Here we utilize the theory of integrated taxonomy to discuss the speciation of the Holarctic Colymbetes paykulli water beetle complex, which historically has included up to five species of which today only two are recognized. Three delimitation methods are used; landmark based morphometry of body shape, variation in reticulation patterns of the pronotum exo-skeleton and sequence variation of the partial mitochondrial gene Cyt b. Our conclusion is that the Palearctic and Nearctic populations of C. paykulli are given the status of separate species, based on the fact that all methods showed significant separation between populations. As a consequence the name of the Palearctic species is C. paykulli Erichson and the Nearctic species should be known as C. longulus LeConte. There is no clear support for delineation between Palearctic and Nearctic populations of C. dahuricus based on mtDNA. However, significant difference in size and reticulation patterns from the two regions is shown. The combined conclusion is that the C. dahuricus complex needs a more thorough investigation to fully disentangle its taxonomic status. Therefore it is here still regarded as a Holarctic species. This study highlights the importance to study several diagnosable characters that has the potential to discriminate evolutionary lineage during speciation.

Show MeSH
Related in: MedlinePlus