Tag Archives: Mollusca

Door #21: A Norwegian oddity

In 1939 the Swedish malacologist Nils Odhner described the nudibranch Berghia norvegica based on two specimens collected at Frøya and Stjørna in the mouth of the Trondheimsfjord.

After its original description this species has been found very few times, the first of them by Hennig Lemche a Danish malacologist who in 1958 collected a single specimen, today housed at the Natural History Museum of Bergen (ZMBN 62033). The importance of this specimen, until recently the only one apparently available in museum collections, was demonstrated by its use in a systematics review of the genus Berghia recently completed by a team of Spanish and American researchers.

The original description of Berghia norvegica is fairly detailed, but was based on preserved specimens and therefore the colouration of this species remained elusive until very recently. For over half a century nothing was known about the colouration of this beautiful and unique animal and is only in 2011 and subsequent years that Berghia norvegica is finally rediscovered by divers and researchers participating in the NudiSafaris organized at Gulen in Sogn og Fjordane just north of Bergen.

These recent discoveries revealed the extreme beauty of this delicate animal and generated the first live images of this endemic and emblematic species of the Norwegian fauna, which we here illustrate with a photograph taken at Gulen on March, the 15^th of 2014 at 38 m deep and kindly made available by Kåre Telnes author of the website “The Marine Fauna and Flora of Norway”.

The sea slug Berghia norvegica, an endemic species from Norway. Photo: Kåre Telnes.

Suggested reading:

Carmona, L., Pola, M., Gosliner, T. M. & Cervera, J. L. 2014. The Atlantic-Mediterranean genus Berghia Trinchese, 1877 (Nudibranchia: Aeolidiidae): taxonomic review and phylogenetic analysis. Journal of Molluscan Studies, 80: 482–498.

Evertsen, J. & Bakken, T. 2013. Diversity of Norwegian sea slugs (Nudibranchia): new species to Norwegian coastal waters and new data on distribution of rare species. Fauna Norvegica, 32: 45–52.

Odhner, N.H. 1939. Opisthobranchiate Mollusca from the western and northern coasts of Norway. Det Kongelige Norske Videnskabernes Selskabs Skrifter, 1: 1–93.

Door #18: A photosynthetic animal

You may already be confused with the title, but you did read it well! Animals can do photosynthesis and most incredibly some species are more efficient than plants or algae. Yet, this achievement is not for all; you must be special, you must be unique…, you must be a sapsucking slug!

Ercolania sp. feeding inside algae (Photo: M. Malaquias)

This is a process named kleptoplasty (= chloroplast symbiosis; see Door #2 of this calendar series) where the slug while feeding from the plant tissue does not digest the chloroplasts but instead migrate these organelles to specific parts of the body where they remain active producing sugars that become available to the slug.

There are two species of sapsucking slugs with a remarkable life-history. The spectacular and rare tropical species Ercolania endophytophaga and E. kencolesi both only known from Australia do not retain chloroplasts as other species do, but they do feed on algae, however, only on a very special kind – the green grape-algae of the Order Siphonocladales. These are syncytial algae made of massive single cell grape-shaped structures which the animal pierce to move in and leave inside until “green-matter” is available.

detail of Ercolania sp. inside algae (Photo: M. Malaquias)

I was very fortunate to find one of this slugs back in January 2014 in southern Mozambique. Usually one has to collect a large quantity of algae to carefully search through later on in the lab and hope for the best! However, in that afternoon while sampling in a beautiful shallow tidal tropical reef in Paindane sluggishly looking at a facies of a “grape-alga” growing over a boulder I suddenly notice a tiny animal moving gently inside the algae. I grabbed a few bunches of algae into my sampling jar to look at later on…, and voilà… I was rewarded with a few specimens of one of this spectacular and difficult slugs most probably an undescribed species, the first from the Indian Ocean.

Ercolania sp. after removal from algae (Photo: M. Malaquias)

-Manuel

Door #15: Guest researchers: Ivan

Ivan Nekhaev from Murmansk came to the University museum in November for a two week stay where he examined some of our mollusc collection. He kindly agreed to participate in our Advent blog adventure, and here is what he had to say:

The main goal of my work at the University Museum of Bergen was studying of minute snails of the family Rissoidae (and drinking a couple gallons of coffee as well :-)).

Rissoids, like many gastropod groups, are more diverse in tropical and subtropical waters whereas the number of species reached northern areas in their distribution is remarkably low: within the several hundreds of northern Atlantic rissoid species, slightly more than dozen of species are know from the adjacent part of the Arctic Ocean. Nonetheless, anatomy for the majority of species had never been investigated and hence the taxonomical status and generic position of some Arctic representatives of the family is questionable, while the accurate data on species composition are still absent for many regions of the Eurasian Arctic.

During my work with the collections of the University Museum I investigated morphology of ten Scandinavian and Arctic species. These data will be used in revision of Eurasian Arctic rissoids and provide me with a good material for the further investigations in “southern” rissoidean snails.

-Ivan

Door #14: A world of colour and slime

Welcome to the world of Nudibranchs!

Flabellina rubrolineata (Mozambique) Photo: M. Malaquias

The nudibranchs are among the most beautiful animals in our seas. The palette of colours, shapes, and adaptations depicted by this group of gastropod molluscs has no parallel. Some species have no more than few millimetres where others can reach nearly half a meter. Some have a smooth skin, others are covered with long and delicate appendices.

Chromodoris boucheti (Mozambique) Photo: M. Malaquias

Phillidia ocellata (Mozambique) Photo: M. Malaquias

Most are benthic, but some are pelagic drifting with the oceanic currents. Nudibranchs feed on sponges, bryozoans, crustaceans, and cnidarians and even can incorporate in their tissues nematocysts sequestered from their prey which they use in self-defence. Probably, the most striking feature of these gastropods is the lack of a shell and presence of bright colours. These colours are usually a warning signal indicating the presence of deterrent chemicals some of them with pH values as low as 1 or 2. Some of these chemicals are biologically active and have been investigated for the treatment of several types of cancer diseases.

Flabellina pedata (Norway) Photo: M. Malaquias

Polycera quadrilineata (Norway) Photo: M. Malaquias

-Manuel

Door #11: Just a white blob?

Colobocephalus costellatus repainted from M. Sars (T.R. Oskars)

When researching small, obscure sea slugs you are bound to run into surprises. Partly because it often takes a long time between discovery and identification, and also because a lot of the really interesting stuff is first revealed when new methods become widely available.

In 2011 a team of researchers from the Invertebrates collection were sampling specimens in Aurlandsfjorden for the Invertebrate collections and range data for the Norwegian Biodiversity Information Centre (Artsdatabanken). Among other interesting critters they found a 2 mm long white blob. While not initially impressive this small blob turned out to be the enigmatic cephalaspidean sea slug Colobocephalus costellatus (Cephalaspidea: Heterobranchia) described by Michael Sars from Drøbak in 1870. At the time of its re-discovery it was thought that this species, which is unique for Norway, had not been seen or collected since M. Sars first laid hands on it 145 years ago (more (in Norwegian) here). However, you continuously discover more information in the course of scientific work. During their work on the enigmatic slug Lena Ohnheiser and Manuel Malaquias found in the literature that the species had in fact been discovered a couple of times since 1870, first by Georg Ossian Sars in Haugesund some years after his father, and more recently by Tore Høisæter of Bio UIB in Korsfjorden outside Bergen.

Still, no in-depth analyses have been done on this species since M. Sars until Nils Hjalmar Odhner of the Swedish Natural History Museum drew the animal from the side showing some of the organs of the mantle cavity.

Most authors have had real difficulties to place this slug within the cephalaspids, and M. Sars even thought is possible that the slug might not be an opisthobranch. Some placed it within Diaphanidae based only on the globular shell, a family that has been poorly defined and often used as a “dump taxon” for species that hare hard to place. Yet others thought it might even be the same as the equally enigmatic Colpodaspis pusilla, which has been suggested to be a philinid sea slug (flat slugs digging around in mud and sand).

What was unique about the most recent find was that this was the first time it was collected alive and photographed with high magnification. The material was also so fresh that Lena and Manuel could dissect the animal and study its internal organs. In their 2014 paper “The family Diaphanidae (Gastropoda: Heterobranchia: Cephalaspidea) in Europe, with a redescription of the enigmatic species Colobocephalus costellatus M. Sars, 1870” they tried to resolve the relationships between these globe shelled slugs. What they found was that Diaphanidae was likely not a real grouping of species, containing at least three distinct groups, where one group was Colobocephalus and Colpodaspis, which were closely related to each other, but also quite distinct.

Colobocephalus costellatus M. Sars, 1870. Photo: Lena Ohnheiser, CC-BY-SA. Also featured on http://www.artsdatabanken.no/File/1292

Another new development with the sampling in Aurlandsfjorden was that the slugs were preserved in alcohol rather than formalin. Formalin is good for preserving the morphology of animals, but it destroys DNA. On the other hand, alcohol is perfect for preserving DNA. This lead to C. costellatus to be included in a 2015 DNA based phylogenetic analysis of cephalaspidean sea slugs.

Modified Tree from Oskars et al. (2015)

This resulted in that the slug was found to be indeed an Opisthobranchia, and as Lena and Manuel thought, Colobocephalus and Colpodaspis were placed in their own family, Colpodaspididae. Whereas the traditional “Diaphanidae” was split apart. Even weirder was the sea slugs that were shown to be the closest relatives of Colpodaspididae, which were neither the philinids or the diaphanids. The closest relatives turned out to be slugs that are equally as weird and unique as Colpodaspididae, namely the swimming and brightly colored Gastropteridae (sometimes called Flapping dingbats) and the Philinoglossidae, which are tiny wormlike slugs that live in between sand grains.

*Cousin Meeting*
– “You sure we are related?”
– “Well, the scientists seem to think so. I see no reason to waste a good party!”

So it took 145 years from its discovery before Colobocephalus became properly studied and its family ties revealed, but it is still mysterious as we do not know much about their ecology or diet.

Suggested reading:

Colobocephalus costellatus: http://www.biodiversity.no/Pages/149747

Colpodaspis pusilla: http://www.biodiversity.no/Pages/149766

Philinoglossa helgolandica: http://www.biodiversity.no/Pages/149915

Høisæter, T. (2009). Distribution of marine, benthic, shell bearing gastropods along the Norwegian coast. Fauna norvegica, 28.

Gosliner, T. M. (1989). Revision of the Gastropteridae (Opisthobranchia: Cephalaspidea) with descriptions of a new genus and six new species. The Veliger, 32(4), 333-381.

Odhner, N.H. (1939) Opisthobranchiate Mollusca from the western and northern coasts of Norway. Kongelige Norske Videnskabers Selskabs Skrifter, 1939, 1–92.

Ohnheiser, L. T., & Malaquias, M. A. E. (2014). The family Diaphanidae (Gastropoda: Heterobranchia: Cephalaspidea) in Europe, with a redescription of the enigmatic species Colobocephalus costellatus M. Sars, 1870. Zootaxa, 3774(6), 501-522.

Oskars, T. R., Bouchet, P., & Malaquias, M. A. E. (2015). A new phylogeny of the Cephalaspidea (Gastropoda: Heterobranchia) based on expanded taxon sampling and gene markers. Molecular phylogenetics and evolution, 89, 130-150.

Sars, M. (1870) Bidrag til Kundskab om Christianiafjordens fauna. II. Nyt Magazin for Naturvidenkaberne, 172–225.

-Trond

Sampling for sea slugs in northern Mozambique (East Africa)

The “tree house”, headquarters of the Conservation and Research project of Vamizi Island

An undescribed species of an aeolid. Vamizi Island.

The tropical waters of the Indian Ocean are part of the world’s richest biogeographical region – the Indo-West Pacific (IWP), where diversity picks its high in the “Coral Triangle” an area confined by the Philippines, Indonesia, and Papua New Guinea.

Within this vast realm, the east coast of Africa is probably the least studied area and Moçambique with one of the largest coastlines in the region and pristine mangrove, seagrass, and coral habitats hides a high and still largely unknown diversity of opisthobranch gastropods (sea slugs).

Phyllidia ocellata. Vamizi Island

During January–February of 2014 I had the opportunity to sample in southern Moçambique together with local colleagues from the Zavora Marine Lab. The results have been so promising that we decided to organize a new fieldtrip but, this time to explore the fauna in the northern tropical latitudes of the country. In collaboration with the University Lúrio in Pemba and the Vamizi Conservation and Research Station managed by the International Union for Conservation of Nature (IUCN), we setup during May 2015 a two weeks fieldtrip to Vamizi Island, a remote pristine sanctuary located in the northern range of the Quirimbas archipelago. The goals were to continue the inventory of the sea slug fauna of Mozambique and Indian Ocean but also to collect specific material for several ongoing projects at the University Museum of Bergen (Natural History) related to the systematics, biogeography, and speciation of these molluscs.

Cerberilla ambonensis. Vamizi island

The first challenge was to reach Vamizi! Four flights, a five hours 4-wheels drive, and at last a boat trip – all of it during four days! But, the sight over the turquoise, calm, and warm waters of Vamizi was breathtaking and well worth the effort! We were very well welcomed by the team of the Conservation and Research Project of Vamizi and the management of Vamizi Island, which have provided all the necessary conditions for a successful and pleasant work.

The white sandy beaches and turquoise waters of Vamizi Island

The pristine coastline of Palma in northern Mozambique.

As the following days would unravel the pristine coral reefs, seagrass meadows and mangroves would not disappoint with their incredible diversity of sea slugs and all kinds of colourful marine live. Yet, and contrary to the experience of the previous year where we have collected in several southern sub-tropical areas of Moçambique (Vilankulo, Barra, Paindane, Zavora), this time was not so easy to find sea slugs and often each of us would not collect more than 4 to 10 specimens per dive; but steadily over the 2-weeks of fieldwork we reached the exciting number of about 85 species, with approximately 60 new records for Mozambique and around 14 new to Science. This seems to be a pattern on many pristine tropical areas; low abundances but high diversity of sea slugs.

Photographing the daily catch

The “crew”. Left to right: Erwan Sola (University of KwaZulu-Natal), Isabel Silva (University Lúrio, Pemba / Vamizi Conservation and Research Project), Yara Tibiriçá (Zavora Marine Lab), Manuel Malaquias (University Museum of Bergen), and Joana Trindade (Vamizi Conservation and Research Project)

Transferring specimens to ethanol at Palma beach (Palma village not far from the border with Tanzania), under the puzzled eyes of a group of locals.

University Lurio. Newly graduated students with supervisors and opponents.

The farewell to Vamizi was not easy; the beauty, warm, and peaceful atmosphere of Vamizi together with its incredible underwater diversity and colours will last surely forever in our memories. Yet, the journey was not over! We headed to the town of Pemba for the last three nights where some formalities were still on the agenda.

Professor Isabel Silva from the University Lúrio in Pemba and member of the Vamizi Island Conservation and Research Project and a join-organizer of our expedition, have invited each member of the team to give a seminar at the university and to act as opponents on the defence of several theses of “licenciatura”. While my colleagues have talked about the sea slugs of Moçambique and the coral reefs of Vamizi Island, I decided to get a away from my field of research (but not of interest!) and discourse about “wired animals” such as loriciferans, xenoturbellids, kinorhynchs, and others… Biological diversity is definitely much more than turtles, sharks, whales, and manta-rays…, even goes beyond colourful sea slugs!

Melibe sp. Vamizi Island.

Is this a slug? Yes it is! Marionia arborescens. Vamizi Island.

Chromodoris cf. quadricolor. Vamizi Island.

Chromodoris boucheti. Vamizi Island

Chelidonura punctata. Vamizi Island.

Chelidonura mandroroa. Vamizi Island.

Chelidonura electra. Vamizi Island.

Phyllodesmium cf. magnum. Vamizi Island.

Cadlinella ornatissima. Vamizi island.

Baby green turtles recovered from a damaged nest, with a rare case of albinism in this group of reptiles.

Conservation “on the move”; Release of green baby turtles on the beach at Vamizi Island.

Philinopsis pilsbryi. Vamizi Island.

Coconut crab. Extinct to nearly extinct in many islands of the Indo-Pacific. Vamizi Island.

Another resident of Vamizi Island locally named "jibóia".

A “slimy” resident of Vamizi Island locally named “jibóia”.

A kingfisher bird. Vamizi Island.

An uninvited guest in my bedroom.

A weaver bird. Vamizi Island.

-Manuel

Uncovering the origin of species in the Caribbean region – fieldwork in the Florida Keys

The lab building at Mote (summerland Key)

The tropical western Atlantic and in particular the Caribbean is the second most diverse marine region in the World only outnumbered in species by the Indo-West Pacific. The processes that lead to this richness are not fully understood, but the diversity of habitats, the network of islands and cays, the uplift of the Isthmus of Panama, and the various periods of transient allopatry caused by sea level changes during the Plio-Pleistocene epochs have most likely played a role.

The canal just off the Mote Lab

Anne’s beach (Islamorada); a sandy flat with patches of seagrass and coral

A mooring area with lined by mangroves with the bottom covered by seagrass and algae (Key Largo)

Mangroves at Summerland Key

A Key deer (Odocoileus virginianus clavium). An endemic subspecies of the American white-tailed deer

The iguana is an exotic species very common in the Keys

Pelicans, a daily presence in the Keys

At the Section for Natural History at the University Museum of Bergen we are investigating the causes and timing of marine diversification in the Caribbean using as model a cryptic species complex of a gastropod (the Bulla occidentalis species-complex). This project led us previously to sample in places like Brazil, Venezuela, Guadeloupe, Panama, the Bahamas, and Bermuda and benefited from samples from many other places collected and kindly provided by several colleagues.

The Most Wanted! Bulla occidentalis (Key Largo)

At night sorting through the daily catch

A preliminary molecular phylogenetic analysis of the data have yielded intriguing results with specimens from the Florida Keys depicting an unexpected level of isolation hardly sharing any haplotypes with “conspecifics” from close by neighboring areas like the Florida Peninsula and Cuba. Nevertheless, the reduced number of specimens that we had available from the Florida Keys hampered any sound testing of this trend. Therefore, a fieldtrip to the Keys was organized between the 7–16 January 2015 in order to collect additional specimens from the local representative of the Bulla occidentalis species-complex.

Spurilla braziliana (Key Largo)

Phylaplysia engeli blending with its preferred habitat – seagrass leaves

Hermaea cruciata (Key Largo)

Haminoea sp. (Key Largo)

The Florida Keys are an arc-shaped coral archipelago located off the southern coast of Florida, dividing the Atlantic Ocean to the east from the Gulf of Mexico to the west. The Keys form the southernmost portion of the continental United States; they begin at the southeastern coast of the Florida peninsula, about 24 km south of Miami, and extend in a arc to Key West, the southernmost of the inhabited islands, and on to the uninhabited Dry Tortugas, just 140 km from Cuba.

The base for the all operation was set at Mote Marine Tropical Laboratory in Summerland Key near the southern tip of the Keys. Pleasant accommodation with sea views, a lab equipped with microscopes and seawater on the tap, plus my little red Mazda rented at the Miami airport (by the way… for a week it became the smallest car to ride the roads of the Keys!) were the ingredients to what turn into a very successful fieldtrip.

The Keys stretch over 150 km and a great amount of time was spent finding and exploring good sampling sites. Those varied from mangrove areas with seagrass beds, sandy beaches with patches of seagrass and clumps of coral, to areas densely vegetated by mangroves, algae and seagrass. At the end two populations of Bulla occidentalis were found plus many other spectacular sea slugs. This material is now housed in our systematic collections and will help unraveling the “entrails” that underlie marine speciation and biogeography in the tropical western Atlantic.

Haminoea antillarum (Key Largo)

Elysia subornata (Key Largo)

Elysia papillosa (Key Largo)

Elysia crispata (Key Largo)

Elysia cornigera (Key Largo)

Dondice occidentalis (Key Largo)

Cratena cf. piuatensis (Key Largo)

Costasiella ocellifera (Key Largo)

Chelidonura berolina (Key Largo)

A red form of ?Dondice occidentalis (Key Largo)

World Congress of Malacology, Azores, July 2013

By Manuel Malaquias

The World Congress of Malacology is the major scientific international meeting in the field of malacology (the study of molluscs) and takes place every third year.

Five of six delegates from the University Museum of Bergen. From left to right: Trond Oskars, Andrea Zamora, Christiane Todt, Manuel Malaquias, Lena Ohnheiser

This year the event was hosted by the University of the Azores in the island of São Miguel between the 21 and 28 of July. Over 400 enthusiastic scientists from all over the World gathered in the middle of the Atlantic Ocean to discuss during five days the latest advances in this science covering various aspects of phylogenetics, biodiversity, ecology, palaeontology, conservation, pest management, adaptations to extreme environments, biogeography, speciation, etc.

Trond Oskars (master student) presenting part of his master thesis on the systematics of cephalaspidean gastropods at the Opisthobranchs Symposium

A delegation from the University Museum comprised by six scientists and students have participated in the event, namely Christiane Todt (post-doctoral researcher), Lena Ohnheiser (research assistant), Andrea Zamora (PhD candidate), Nina Mikkelsen (PhD candidate), Trond Oskars (MSc. student), and Manuel Malaquias (assistant professor). In total, members of the University Museum were co-authors in 14 scientific contributions: four posters and 10 talks presented at the Aculifera and Opisthobranchs symposiums.

The next congress will take place in Penang, Malaysia in 2016 and we look forward for it!

The spectacular volcanic “Lagoa do Fogo” in São Miguel Island, Azores

The Invertebrate Collections

The University Museum of Bergen