Three sibling species of didemnid ascidians from northern Norway: Didemnum albidum (Verrill, 1871), Didemnum polare (Hartmeyer, 1903), and
Abstract: Recent advances in taxonomy have disclosed the prevalence of cryptic sibling species in marine systems. In didemnid ascidians, morphological variation between species is often slight, and many species may have been overlooked. Species boundaries within this group are often equivocal, and p...
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ftciteseerx:oai:CiteSeerX.psu:10.1.1.486.9685 2023-05-15T16:13:43+02:00 Three sibling species of didemnid ascidians from northern Norway: Didemnum albidum (Verrill, 1871), Didemnum polare (Hartmeyer, 1903), and Jessica A. Marks The Pennsylvania State University CiteSeerX Archives application/pdf http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.486.9685 http://folk.uib.no/nzljm/marks1996.pdf en eng http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.486.9685 http://folk.uib.no/nzljm/marks1996.pdf Metadata may be used without restrictions as long as the oai identifier remains attached to it. http://folk.uib.no/nzljm/marks1996.pdf text ftciteseerx 2016-01-08T08:15:07Z Abstract: Recent advances in taxonomy have disclosed the prevalence of cryptic sibling species in marine systems. In didemnid ascidians, morphological variation between species is often slight, and many species may have been overlooked. Species boundaries within this group are often equivocal, and patterns among taxa are reminiscent of those formed by reticulate evolution in plants. Specimens of the sessile colonial ascidian Didemnum albidum (Verrill, 1871) were examined for life-history and morphological characters and found to constitute at least three sympatric sibling species. One of these, Didemnum romssae, is described here as a new species. Colonies were collected from hard-bottom assemblages in Troms and Finnmark counties in northern Norway. Zooid morphology in D. romssae is similar to that of D. albidum, but varies within each species, even for traits usually considered specific. Didemnum romssae is proposed as a distinct species on the basis of consistent differences in (i) the shape and size of calcium carbonate spicules within the common test; (ii) larval size and the number of lateral ampullae; (iii) timing of reproduction; and (iv) the absence of a seasonal nonfeeding, overwintering stage, which occurs in D. albidum. Examination of specimens from museum collections considered synonymous with D. albidum confirmed the presence of a third species, Didemnum polare (Hartmeyer, 1903), which differed from the other two species in zooid and larval morphology as well as spicule shape. Complexes of sibling species such as these provide a tractable system for studying the consequences of life-history variation among closely related taxa. Text Finnmark Northern Norway Finnmark Troms Unknown Norway |
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Abstract: Recent advances in taxonomy have disclosed the prevalence of cryptic sibling species in marine systems. In didemnid ascidians, morphological variation between species is often slight, and many species may have been overlooked. Species boundaries within this group are often equivocal, and patterns among taxa are reminiscent of those formed by reticulate evolution in plants. Specimens of the sessile colonial ascidian Didemnum albidum (Verrill, 1871) were examined for life-history and morphological characters and found to constitute at least three sympatric sibling species. One of these, Didemnum romssae, is described here as a new species. Colonies were collected from hard-bottom assemblages in Troms and Finnmark counties in northern Norway. Zooid morphology in D. romssae is similar to that of D. albidum, but varies within each species, even for traits usually considered specific. Didemnum romssae is proposed as a distinct species on the basis of consistent differences in (i) the shape and size of calcium carbonate spicules within the common test; (ii) larval size and the number of lateral ampullae; (iii) timing of reproduction; and (iv) the absence of a seasonal nonfeeding, overwintering stage, which occurs in D. albidum. Examination of specimens from museum collections considered synonymous with D. albidum confirmed the presence of a third species, Didemnum polare (Hartmeyer, 1903), which differed from the other two species in zooid and larval morphology as well as spicule shape. Complexes of sibling species such as these provide a tractable system for studying the consequences of life-history variation among closely related taxa. |
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The Pennsylvania State University CiteSeerX Archives |
format |
Text |
author |
Jessica A. Marks |
spellingShingle |
Jessica A. Marks Three sibling species of didemnid ascidians from northern Norway: Didemnum albidum (Verrill, 1871), Didemnum polare (Hartmeyer, 1903), and |
author_facet |
Jessica A. Marks |
author_sort |
Jessica A. Marks |
title |
Three sibling species of didemnid ascidians from northern Norway: Didemnum albidum (Verrill, 1871), Didemnum polare (Hartmeyer, 1903), and |
title_short |
Three sibling species of didemnid ascidians from northern Norway: Didemnum albidum (Verrill, 1871), Didemnum polare (Hartmeyer, 1903), and |
title_full |
Three sibling species of didemnid ascidians from northern Norway: Didemnum albidum (Verrill, 1871), Didemnum polare (Hartmeyer, 1903), and |
title_fullStr |
Three sibling species of didemnid ascidians from northern Norway: Didemnum albidum (Verrill, 1871), Didemnum polare (Hartmeyer, 1903), and |
title_full_unstemmed |
Three sibling species of didemnid ascidians from northern Norway: Didemnum albidum (Verrill, 1871), Didemnum polare (Hartmeyer, 1903), and |
title_sort |
three sibling species of didemnid ascidians from northern norway: didemnum albidum (verrill, 1871), didemnum polare (hartmeyer, 1903), and |
url |
http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.486.9685 http://folk.uib.no/nzljm/marks1996.pdf |
geographic |
Norway |
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Norway |
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Finnmark Northern Norway Finnmark Troms |
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Finnmark Northern Norway Finnmark Troms |
op_source |
http://folk.uib.no/nzljm/marks1996.pdf |
op_relation |
http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.486.9685 http://folk.uib.no/nzljm/marks1996.pdf |
op_rights |
Metadata may be used without restrictions as long as the oai identifier remains attached to it. |
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1765999560436482048 |