Category Archives: Mollusca

Guest researcher: Sara Castillo

“Opisthobranch” gastropods from West Africa

Dr Sara Castillo has recently finished her PhD (September 2017) with a thesis on the taxonomy and diversity of gastropods and bivalves from North-west Africa (Morocco to Sierra Leone), based on material collected during cruises of the Norwegian and FAO Nansen Programme and other scientific projects.

The Natural History Museum of Bergen has since 2005 collaborated in the benthic sampling of the Nansen Programme, and between 2013–16 the Museum was awarded funding from the American JRS Biodiversity Foundation to aid on the study and DNA barcode of the western African invertebrate benthic fauna. During this period Sara visited Bergen to participate in a workshop on to the taxonomy of western Africa bivalves organised by the Museum. The “opisthobranchs” gastropods (sea slugs and other related lineages) were not covered by Sara Castillo’s research and in Bergen we have so far only studied in depth the philinid snails (fam. Philinidae sensu lato).

Sara is visiting the Museum for 6-weeks (1^st Nov–15^th Dec) to study both ours and the University of Vigo’s collection of opisthobranchs from West Africa. Representatives of all morphotypes will be DNA barcoded and identified to species level. Because of its diversity and difficult taxonomy in western Africa the nudibranch family Arminidae will receive special attention and the barcoding work will be complemented with anatomical characterization of species backed by scanning electron microscopy. Our goals are to produce an inventory of the West Africa “opisthobranchs” collected during the Nansen programme and a taxonomic review of arminid nudibranchs from the region.

DNA-barcoding: update

Yesterday, Endre and I attended an event where the different units of the University of Bergen were invited to “..present ongoing digitalisation projects, tools and methods, and future digital solutions.”

We brought with us a poster titled “Data con carne – sources of new knowledge on biodiversity” (in Norwegian), where we presented how our barcoding efforts on both African and Norwegian material are parts of a global undertaking of building a “library of life”, and how using huge databases such as BOLD can help us gain better understanding of biodiversity – and on where to focus our efforts in unraveling the taxonomy.

There is a very real challenge connected with estimating biodiversity when many of the species are still undescribed, as is the case with many invertebrates, especially the more obscure and diminutive groups. In such cases, barcoding can serve as a tool in screening for biodiversity, and aid the taxonomists in identifying areas where the taxonomic resolution is poor.

There is a global effort underway to establish a library of short, species specific genetic sequences. These standardized genetic sequences (“barcodes”) consists of a segment of approximately 650 base pairs of the mitochondrial gene cytochrome oxidase c subunit 1 (COI). You can read more about DNA barcoding on WIKIPEDIA.

For MIWA, we have submitted over 2700 tissue samples from over 600 morphospecies for DNA barcode sequencing through the BOLD-pipeline, where the lab work is done in Guelph, Canada, and the data is uploaded to the Barcode of Life Data Systems (BOLD Systems) .

Out of these, 1450 sequences have been obtained (54% sequencing success rate), and these cluster into close to 550 BINs (OTUs) – suggesting that the diversity may be (much!) higher than what our preliminary investigations reveal. This is not so surprising, considering how hugely diverse and little studied the invertebrate fauna of the GCLME and the CCLME is.

Below is an interactive map of the submitted samples, you can click on the stations to see the specimens that have been sent from that location, and whether or not they have gotten a barcode. You can also follow this link to find the map

What we find is that it is crucial to be able to go back and reexamine the material post-barcoding, and that is where the “con carne” part of our poster came from;

Our barcoding revealed several examples of mismatching taxonomic identifications amongst researchers in different labs and institutions in different countries. This illustrates a major challenge, as it has been shown that when benthic fauna is used in standardized methods for quality assessment and monitoring, mismatching identifications produced by different identifiers can have strong effects on indexing and valuation of ecological conditions in the same habitat.

For DNA barcoding to be useful, it is absolutely neccessary that the correlation between species name, specimen, and barcode is correct (or at least as close to it as we can get, if the species is undescribed).

We must first build this reference library before barcoding can be reliably used for identification of unknown organisms. Hence it is imperative that the voucher specimens that correspond to the genetic barcodes are deposited in a museum where it will be preserved and made available for research.

-Endre & Katrine

#InvertebrateCalendar

We are running a calendar count down from the 1st to the 24th of December on our collections blog, and MIWA is frequently featured!

Some of the topics covered in the first half – ranging from sea spiders to sciart!

Click to have a look

Mapping our barcoding efforts

Here is a interactive map of all the samples (2175 as we speak!) that we have submitted to the BOLD-database for genetic barcoding.

You can also follow this link to find it.

All the stations from which we have submitted specimens for barcoding

By clicking around on the map you can see how many specimens we have submitted from each station, as well as photos of the animals and wether or not the sequencing was successful and resulted in a genetic barcode.

By clicking on a station, you get the information about which animals have been sequenced – here two brittle stars that were both successfully barcoded

The samples we have submitted (so far – there are still plans to do more!) include several animal main taxa; Crustaceans, Echinoderms, Molluscs and Polychaetes. These animals have been sorted out and identified by employees at the invertebrate collections, and by visiting guest researchers who have come here to work in the material – so it is very much a combined effort behind this.

# of submitted specimens (animals) from each phylum

Not all our material is suited for genetic analyses; fixation in formaldehyde gives well preserved specimens that are well suited for morphological examinations – which is the backbone of taxonomy – but it distorts the DNA so that the samples are not eligible for molecular work.
Provided that the material has been fixated in a DNA-friendly way (i.e. in ethanol), there is a lot of work to be done before we are left with identified specimens. We wrote a bit about the sorting of samples her: “biodiversity in a dish”.

We are still working actively with this material and with the results we are getting – some of it has already been published – se our list of publications here – and more is on the way.

New species of West African snails

Our studies of mollusks have revealed new species of philinid snails. They are described in a paper that was published today in the Zoological Journal of the Linnean Society with open access: http://onlinelibrary.wiley.com/doi/10.1111/zoj.12478/full

We used both morphological techniques and DNA-based species discrimination methods in this study and DNA-barcodes have been uploaded to the BOLD-database. Laona nanseni was named as a tribute to the Nansen programme and Philine schrammi in honour of J. R. Schramm, who founded JRS Biodiversity Foundation, an important sponsor of our work.

Laona nanseni new species

Philine schrammi new species

Mysterious limpet

Management of species requires information about their habitat, ecology, population size, geographical range, exploitation and environmental threats. It usually should go without saying that confident species identification is a key factor in the acquisition of such knowledge. DNA barcoding may help to establish a relative objective identity tag on taxa and to place local and regional populations in a global context with their closest relatives.

We recently published a paper about a species of Cellana that is closely related to C. toreuma in the Indo-Pacific. More research is needed to assess if the Gulph of Guinea population is a separate species or a population with relatively recent connections to the Indian Ocean.

The paper and Additional file are Open Access here:

http://mbr.biomedcentral.com/articles/10.1186/s41200-016-0059-9

Cellana species near torreuma from Nigeria

Cellana species near toreuma from Nigeria

Available DNA barcodes to gastropods

Our joint efforts in producing DNA barcodes for West African gastropods have been moderately successful with sequences generated for about 55 % of the species.

Data for successful as well as failed specimens are available on this page.

A pop-up window is displayed by clicking on the blue markers. In this example, there is a BARCODED specimen of Nassarius atlantideus. Notice the processID, MIWAM050-13, which can be used to access the specimen in the BOLD database.

Open BOLD in your web browser. Select “Databases from the top menu. Type the processID in the search field and it will bring you to the species information page,

Unravelling the diversity of Bivalve Molluscs of Western Africa

Tellina (Oudardia) compressa

Venus verrucosa

The study of the marine invertebrates of West Africa collected during the “Nansen Project” goes on and this year a second workshop was organized with a focus on the taxonomy of bivalves. Nine days of seclusion in our marine station at Espegrend on the surroundings of the city of Bergen allowed for the necessary tranquility to concentrate in the laborious work of sorting through and identifying thousands of specimens collected between Morocco and Angola by the Norwegian research vessel Dr. Fridtjof Nansen.

Abra alba

This year the “Molluscan” team was strengthen with two extra players; Sara Castillo, a PhD student from Spain enrolled at the University of Vigo and working on the marine fauna of Mauritania and Rudo von Cosel from the Paris Museum of Natural History a recognized authority on the taxonomy of bivalve molluscs.

Aequipecten flabellum

Atrina chautardi

Corbula cadenati

During last year workshop we have implemented a successful “conveyor-belt operation” where each of us was responsible for a specific task (identification, labelling, databasing, imaging, barcoding, etc.). The samples were first organized by morphotypes and then passed into the hands and eyes of our taxonomic experts; a new label with a museum voucher number, species name, locality, etc., was added, and the samples were then databased, photographed, and some selected for DNA barcoding. In parallel several invited participants received training in the various technical and scientific aspects of this operation.

Cuspidaria cuspidata

Falsolucinoma leloeuffi

This year we have again implemented the same successful strategy; Lena Ohnheiser (University Museum of Bergen) was responsible for the database, labelling, and “in between” automontage imaging, Rudo von Cosel, José Pedro Borges (Portuguese Institute of Malacology), Kouakou Kouadio (University of Nangui Abrogoua, Côte d’Ivoire), Sidi Moctar (Institut Mauritanien de Recherches Océanographiques et des Pêches), and Sara Castillo for the taxonomic identification, and the author of these lines was the responsible for general imaging of the specimens and overall coordination of the team-work. In parallel Trond Oskars (a PhD student at the University Museum of Bergen) and Endre Willassen (PI of the Marine Invertebrates of Western Africa project) have worked on the preparation of 95 samples for DNA barcoding.

Gari fervensis

Laevicardium senegalensis

Noetiella congoensis

Our colleague Rudo von Cosel has been working for more than 10 years on a comprehensive book about the bivalves from tropical western Africa.

Rudo brought the proofs of his book to the workshop and we can proudly claim to have been the first ones to have ever seen his book assembled! The species illustrations and descriptions were bind together by families and used as identification tools during the workshop. At the end of the week we have databased over 800 lots and identified approximately 125 species. It was very rewarding to realize that our joint effort rendered many new geographical records contributing to better understand the distribution of species and biogeographic processes along the coast of West Africa.

We are very thankful to all participants in the workshop; to all those mentioned along these lines and those who were not but were nonetheless crucial for the success of this very productive week helping with various technical and logistic aspects, contributing to the good atmosphere, and very important keeping everybody “bellies” happy with great demonstrations of cuisine masterskills!

Sinupharus bernardi

-Manuel

Participant snapshots – Sara

Name: Sara Castillo Oñate

Home institution: University of Vigo (Spain) and Spanish Institute of Oceanography

What do you work with at home?

I’m preparing a paper about composition and distribution of macrobenthos from Mauritanian deepwaters, based on samples collected with Agassiz trawl between 150 and 1600m.

I’m also working on mollusc identification (except cephalopods) from CCLME region.

Sara and Lena on board the “Aurelia”

What are you working on here?

I am part of the “Team Mollusca” helping the expert on bivalves Rudo von Cosel and learning a lot about the identification of this group. I’m also separating the mixed mollusc samples to morpho-specie level. This is my first workshop and I’m really happy for the experience.

Participant snapshot – Sidi

Name: Sidi M. Moctar

Home institution: Institut Mauritanien de Recherches Océanographiques et des Pêches (IMROP)Laboratoire d’Ecologie et Biologie des organismes Aquatiques/ Mauritanian Institute of Oceanographic Research and fishing

What do you work with at home?

I am responsible for the studies of ecology, biodiversity and systematics of macrobenthos

What are you working on here?

I am part of the group working on identifying the bivalves that have been collected in the CCLME and GCLME regions.