Open-ocean environments provide few obvious barriers to the dispersal of marine organisms. Major currents and/or environmental gradients potentially impede gene flow. One system hypothesized to form an open-ocean dispersal barrier is the Antarctic Polar Front, an area characterized by marked temperature change, deep water, and the high-flow Antarctic Circumpolar current. Despite these potential isolating factors, several invertebrate species occur in both regions, including the broadcast-spawning nemertean worm Parborlasia corrugatus. To empirically test for the presence of an open-ocean dispersal barrier, we sampled P. corrugatus and other nemerteans from southern South America, Antarctica, and the sub-Antarctic islands. Diversity was assessed by analyzing mitochondrial 16S rRNA and cytochrome c oxidase subunit I sequence data with Bayesian inference and TCS haplotype network analysis. Appropriate neutrality tests were also employed. Although our results indicate a single well-mixed lineage in Antarctica and the sub-Antarctic, no evidence for recent gene flow was detected between this population and South American P. corrugatus. Thus, even though P. corrugatus can disperse over large geographical distances, physical oceanographic barriers (i.e. Antarctic Polar Front and Antarctic Circumpolar Current) between continents have likely restricted dispersal over evolutionary time. Genetic distances and haplotype network analysis between South American and Antarctic/ sub-Antarctic P. corrugatus suggest that these two populations are possibly two cryptic species.
The data in this occurrence resource has been published as a Darwin Core Archive (DwC-A), which is a standardized format for sharing biodiversity data as a set of one or more data tables. The core data table contains 106 records.
This IPT archives the data and thus serves as the data repository. The data and resource metadata are available for download in the downloads section. The versions table lists other versions of the resource that have been made publicly available and allows tracking changes made to the resource over time.
The table below shows only published versions of the resource that are publicly accessible.
How to cite
Researchers should cite this work as follows:
Thornhill et al . 2008. Mol. Ecol. 17 (23), 5104-5117
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The publisher and rights holder of this work is SCAR - AntOBIS. This work is licensed under a Creative Commons Attribution (CC-BY 4.0) License.
This resource has been registered with GBIF, and assigned the following GBIF UUID: 7b967e82-f762-11e1-a439-00145eb45e9a. SCAR - AntOBIS publishes this resource, and is itself registered in GBIF as a data publisher endorsed by Ocean Biodiversity Information System.
The resource data is also available in other formats
|Online dataset||http://www.iobis.org/mapper/?dataset=1979 US-ASCII Plain Text|
|Metadata||http://www.vliz.be/imis/imis.php?module=dataset&dasid=2503 UTF-8 XML|
|Bounding Coordinates||South West [-70, -75], North East [-50, -50]|
|Phylum||Nemertea [ribbon worms]|
marine, harvested by iOBIS