The ChEss TAWNI funds
PROJECT: Systematics of Nautiliniellidae Miura and Laubier, 1990
(Annelida); symbionts of seep and vent bivalves
Grantee: Maite Aguado
Final report
Communities of benthic animals associated with methane seeps—also
known as cold seeps—are considered among the most interesting habitats
because of their great biodiversity and the complex interrelationship of its biota.
However, it is still a challenge to characterize the biotic diversity of these
methane-derived carbonates, before we identify the interactions among all the
groups involved in the dynamics of these ecosystems. One of the groups involved
in these complex interactions are the nautiliniellids, a small group of polychaetes
who are symbionts of deep-sea bivalve molluscs from hydrothermal vents and
cold seeps. My TAWNI project was focused in the study of the systematics of this
family, because so far this group has been poorly studied and its life-history is
poorly understood.
Through the support of the
TAWNI
ChEss
and
Fondation Total grant I was
able to participate in a
collaborative
research
project focused in the
characterization of the
structure, function and
evolution of methanederived
carbonate
ecosystems. I had the
chance to join Dr. Greg
Figure 1. Pictures are examples of Shinkai longipedata
Rouse from the Scripps
Institution of Oceanography (SIO) and his team and participate in a 10-day
cruise to the Costa Rica margin. We collected numerous samples from cold seeps,
and it was a great and unforgettable experience working on the Atlantis boat
(Woods Whole Institution of Oceanography), while being part of the scientific
crew, while being also able to participate in one of the Alvin underwater
submarine dives. We descended more than 1000m, and the scenario that opened
to my eyes was even more astonishing than what I could have ever expected.
During the field-trip we collected dozens of samples of different bivalves
(Acharax sp., Calyptogena sp. and different species of Bathymodielus mussels)
that hosted a high number of nautiliniellids.
After the cruise I stayed one month and three weeks working at the SIO, in
Dr. Rouse lab. During this time, we stuided the nautiliniellid specimens under
different perspectives. 1) Five different species were identified, one associated
with Acharax sp., two associated with Bathymodielus sp. and two with
Calyptogena sp. Three of these species possibly are new taxa. The possibility to
use several cameras and a camera lucida attached to different optic microscopes
and also the use of the scanning electron microscopy (SEM) at SIO allowed me to
compile invaluable morphological data. This information is perfectly illustrated
in a large collection of high quality pictures (in many cases firstly used to
characterize nautiliniellids species). 2) The morphological features were also
necessary to perform the first morphological matrix of nautiliniellids for
phylogenetic analyses. 3) Other material from different geographical areas was
very kindly loaned from different institutions to be compared with our
specimens. 4) Two nuclear genes, 18S rDNA and Histone 3 (H3), and two
mitochondrial genes 16S rDNA and cytochrome c oxydase subunit I (COI) were
sequenced at SIO. The COI sequences were used to perform a distance analysis
that has confirmed our hypotheses about the new species based on their
morphology. The analyses of the four genes and their combination with the
morphology were preformed through Maximum Parsimony (MP), Maximum
Likelihood (ML) and Bayesian inference (BI). Results are now being studied and
will yield the first phylogenetic hypothesis that explains the evolutionary
relationships of Nautiliniellidae with other families of Phyllodocida (Annelida).
All these results will be reported in two manuscripts that will soon be submitted
to different peer review journals. All the morphological and molecular
information will also be incorporated to web-based international databases (i.e.,
ChEssBase and GenBank).
In addition, several samples are being prepared for a Transmission
Electron Microscopy (TEM) study, to compare the digestive tube in
nautiliniellids with other groups such as the family Syllidae. Additionally, during
the cruise I also had the chance to study other polychaetes such as syllids and
chrysopetalids, and found three possible new species. We are also interested in
understanding the coevolution of nautiliniellids and their molluscs hosts. These
additional results will be finished and published once the nautiliniellid project
has concluded. The grant was used to cover my travel costs to go to San Diego from
Spain, my stay at La Jolla, and part of the SEM photographies.
In summary, I consider that my stay in San Diego, working at SIO with Dr.
Greg Rouse and the cruise to Costa Rica have been very productive, and have
invaluably enriched my personal and scientific backgrounds.