Understanding the Biogeography of Marine Worms using Genetic Markers

Project start date: September 2001 - Project end date: September 2002
Project number: 2001-05
Beneficiary: Smithsonian Institution

Final Results

Dr. Anja Schulze completed the travel to Micronesia in November 2001 where she had a very successful collecting trip. She has subsequently been working on the materials collected and has complete a manuscript detailing the phylogeography of the Palolas based on the material collected during the grant. This paper demonstrates that the situation is rather more complicated than anticipated:

* First, what Dr. Schultze thought was a single cohesive taxon, Palolo, turns out not to be as cohesive as she had hoped. She had included members of related genera, but must now attempt to place the different subunits of Palolo's in relation to a larger selection of members of the family Eunicidae.
* Second, despite that apparent set-back, what she can show is that there are indeed more than one taxon of palolo's present in the Micronesian waters.
* Perhaps most surprising is that the most common of the Micronesian clades appears to be an undescribed species; it can be separated from the rest not only on molecular grounds, but also morphologically and will be described as a new species. So the true Palolo, originally named from Fiji Islands appears to be rare elsewhere.

Up to this point in time, most authors have considered the palolo's from around the world to belong to a single species, either named Palolo siciliensis (obviously originally from the Mediterranean Sea) or Palolo viridis, as mentioned above originally from Fiji. These two "taxa" do come out in the same clade, so it is possible that the group in fact contains one extremely widespread species and another species limited to the western Pacific Ocean.
In addition, there are certain areas, Las Perlas in Panama and Ant Atoll in Micronesia appears to contain only a single taxon. This may indicate that either that palolo has recently invaded the area and has not become differentiated, or alternatively that only a single taxon has been available for invasion into these areas.
Parenthetically, in traditional biogeography, Las Perlas would be considered part of the Caribbean Sea, despite its location in the eastern Pacific Ocean. This has been claimed to be due to the very wide open waters between the easternmost islands in the Pacific and the American coastline. However, the distribution of the CO1 haplotype demonstrates that as usual, worms are not very good at following theory!
To paraphrase the old saw: Dr. Schultze has certainly opened a nasty can of worms in this study and have set up a situation in which the added information is likely not only to yield answers, but also very interesting new questions. Without the material collected through the NPF grant, she would not have been in this situation. Creating questions are often a better strategy than yielding final answers.

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