Biopapua / Off Bougainville Island
13 October 2010
We begin October 12 by working far from the coast, on a seamount that we spotted on our marine charts.
We find four specimens of this beautiful Pleurotomariidae gastropod. At first glance, it looks like Petrochocus boucheti , a species known from New Caledonia, but the taxonomist specializing on this group tells us that this specimen belongs to the genus Bayerotrochus .
These hard substrates provide us with many live mollusks, which will feed the "Barcode of Life" (BoL) collection that we have been assembling since 2004. BoL is an international program that aims at advancing the tools used for taxonomic identification.
The idea is to use the information from a fragment of DNA to assign specimens to known species. This involves documenting the variability of this target DNA fragment (the DNA barcode) for specimens examined by specialists and assigned to nominal species.
Specimens serve as references, and are kept in collections (in museums of natural history, mainly). Data (photographs, locality, etc...) associated with specimens, along with their DNA barcodes populate a database that is accessible on the internet ( www.barcodinglife.org).
One of the applications of this tool is the identification of highly damaged or fragmented specimens (such as, for example, the identification of the piece of sashimi in your plate), or eggs and larvae (illustrated in Puillandre et al. 2009 in Molecular Ecology Resources).
Our research teams are involved in this project, particularly for the marine crustaceans and mollusks. Aboard, this involvement requires:
- Taking photos of the crustaceans, as they rapidly loose their colors once submerged in ethanol;
- Separating mollusks from their shells. Individuals retracting within their shell may be poorly preserved, as the ethanol cannot penetrate and fix tissues.
Little is known on the biodiversity of marine organisms, including the ones we collect. One of premise of the “Barcode of Life” project is that the accumulation of genetic data will facilitate the discovery of new species. Indeed, some of the DNA sequences retrieved from our recently-collected specimens may not match anything in our barcode database.
Mere genetic data, however, are not enough to describe new species.
“Integrative” taxonomy is now flourishing. Modern approaches to taxonomy take into account characters that are classically included in taxonomic descriptions (morphological and anatomical characters), and also genetic characters. These approaches also use all the analytical tools available (phylogenetic reconstruction, population genetics, morphometry, etc...). For an illustration of this type of work, see for example Puillandre et al. 2010, in the Journal of Molluscan Studies.
We continue our work off Bougainville on October 13. Unfortunately, the area we chose turns out to be difficult to work on; currents are too strong and substrates are predominantly hard. Once more, the crew is busy with mending the trawl net.
Next stop: the Feni Islands.