Category Archives: Phylogenetics

Evolutionary history of cave shrimps

Machumvi Ndogo - preparing for a dive in the dark

Machumvi Ndogo – preparing for a dive in the dark

In 2008 UiB colleagues Kenneth Meland and Endre Willassen surveyed karst caves in Zanzibar together with Hajj M. Hajj in search for aquatic crustacea. Many of these localities have so-called anchialine conditions in which marine water penetrates inland and can mix more or less with fresh ground water.


Atyid shrimps were sampled in salt water about 300 m inland from the coast.

Atyid shrimps were sampled in salt water about 300 m inland from the coast.

One of these sites had three species of small shrimps of the family Atyidae. The phylogenetic relationships of these shrimps have now been analysed by an international team of “cave men” based on full mitochondrial genome sequencing performed at the University of the Balears.

Molecular clock estimates date the relationship of the Zanzibarian species to other known species in the Atlantic and Indo-pacific  to the Cretaceous period.

Shrimps from Osine Cave

Shrimps from Osine Cave

The paper is available from this link:

Species divergence history of the study group.

Species divergence history of the study group. Click for details.

Congratulations to our latest PhD!

Freshly minted PhD!  (photo: Kenneth F. Bosch)

Freshly minted PhD!
(photo: Kenneth F. Bosch)

Andrea successfully defended her Ph.D. thesis “Dietary specialization and molecular phylogeny of the family Aglajidae (Cephalaspidea: Gastropoda) with species delimitation analysis and biogeography of two genera from the clade Chelidonura sensu lato” earlier today. She was supervised by Manuel A.E. Malaquias from the Department of Natural History, UM, and Henrik Glenner from the Department of Biology.

You can read more about her work here (in Norwegian)

Congratulations and all the best wishes from us!

Below are photos of some of the species, if you are wondering how they look (pics by Manuel)

Guest researchers: Carlo

Untangling the diversity and evolution of Sea Hares

Aplysia parvula; Føllingen, Norway; Photo by Nils Aukan

Aplysia parvula; Føllingen, Norway; Photo by Nils Aukan

Sampling and freezing at Askøy

Sampling and freezing at Askøy

Dr Carlo M. Cunha from the Metropolitan University of Santos in Brazil (Universidade Metropolitana de Santos), a world expert in the diversity and systematics of Anaspidea heterobranch gastropods, visited the Natural History Museum of Bergen for a month during January/February 2017 to study our scientific collection of these molluscs. The visit was funded by the University of Bergen´s Strategic Programme for International Research and Education (SPIRE).

The Museum holds a large amount of material from the Scandinavian region, but also from the Mediterranean, Macaronesia islands, Caribbean, and western Indian Ocean.

These marine molluscs commonly known by sea hares comprise around 90 currently known species and have long been of major interest to biologists because of their large and easily accessible nervous system, which form the basis of numerous neurophysiological works.

Preserved specimen of Aplysia punctata from norway

Preserved specimen of Aplysia punctata from Norway

Dissected specimen of Aplysia punctata from Norway

Dissected specimen of Aplysia punctata from Norway

However, the taxonomy of these molluscs and their evolution are still poorly understood. Dr Cunha is using a combination of molecular and morphological tools to learn more about the worldwide diversity of anaspideans and their phylogenetic relationships.

Dr Cunha visit to Bergen has already resulted in the revision and update of the taxonomy of our Anaspidea collection. The Norwegian species of anaspids were revised and redescribed in detail using electron microscopy and DNA barcoding performed in collaboration with Louise Lindblom (University Museum / Biodiversity Labs).

SEM-image of jaws of Phyllaplysia sp from Florida, USA

SEM-image of jaws of Phyllaplysia sp from Florida, USA

Additionally several other species from around the world were studied and will be integrated in ongoing taxonomic revisions. Keep tuned!


We’ve also had Lloyd visiting recently, you’ll find a post about that on the Marine Invertebrates of Western Africa blog: click here

Door # 18: MSc completed

Congratulations to Jenni, our (former!) master student, who presented her MSc project last Friday!

She has been working on the phylogenetic systematics and evolution of a genus of small marine gastropods called Phanerophthalmus, and she’s done an impressive amount of work.

Phanerophthalmus crawling on seagrass. Photo: M. Malaquias

Phanerophthalmus crawling on seagrass. Photo: M. Malaquias


The project was titled
Systematics, biogeography, and trophic ecology of the genus
Phanerophthalmus A. Adams, 1850 (Mollusca, Cephalaspidea, Haminoeidae) in
the Indo-West Pacific, and was supervised by Manuel Malaquias.

Celebrating our freshly minted MSC with coffee, cakes and bubbles

Celebrating our freshly minted MSC (second from the left in top photo) with coffee, cake and bubbles!

We wish you all the best, Jenni!

Door #17: New master student



Polina Borisova, a first year master student from the Zoological Department of the Moscow State University (Russia), is coming to the Invertebrate Collections of the University Museum of Bergen with a 1-month research visit in January 2017.

Polina is going to work on the bristle worms from the family Lumbrineridae studying the collection from West Africa and Norway. Her project is jointly supervised by Dr. Nataliya Budaeva from the University Museum of Bergen and Dr. Alexander Tzetlin from the Moscow University.

Various Lumbrineridae from West Africa, scale 1 mm (Photos from BOLD).

Various Lumbrineridae from West Africa, scale 1 mm (Photos from BOLD).

Lumbrineridae are the worms with relatively poor external morphology but complex jaw apparatus. The structure of jaws has been traditionally used in the systematics of the family in the generic diagnoses. Polina is utilizing the methods of microCT to study the jaws of lumbrinerids in 3D.

Jaws of Scoletoma fragilis from the White Sea scanned using microCT showing ventral solid mandibles, forceps-like maxillae I and denticulate maxillae II and II, carriers of maxillae are omitted (Photo: P. Borisova)

Jaws of Scoletoma fragilis from the White Sea scanned using microCT showing ventral solid mandibles, forceps-like maxillae I and denticulate maxillae II and II, carriers of maxillae are omitted (Photo: P. Borisova)

Polina is also going to sequence several genetic markers to reconstruct the first molecular phylogeny of the family. This will allow testing the current hypothesis on the intergeneric relationships within Lumbrineridae and will aid in tracing the evolution of jaws within the family.

-Nataliya & Polina

A week of worms in Wales!

Does that not sound appealing?
It was actually a lovely event!

The IPC2016 logo © National Museum Wales

The IPC2016 logo © National Museum Wales

The 12th International Polychaete Conference took place in Cardiff, Wales during the first week of August. These events have been taking place every third year since 1981, and the previous one was in Sydney, Australia in 2013.



Polychaetologists assembled on the steps of the National Museum Cardiff (c) IPC2016

Polychaetologists anno 2016 assembled on the steps of the National Museum Cardiff © National Museum Wales

During an intensive week of presentations and posters spanning topics within Systematics, Phylogeny, Ecology, Methodologies, Biodiversity, Biodiversity and Ecology, Morphology, Reproduction & Larval Ecology, Development, and Polychaete studies, people had the chance to showcase their work, and learn more about what others are working on. The local organising committee invited us to “Have a happy conference, re-connecting with those already known, meeting correspondents for the first time, ans making new connections and new friends” – and I think we can safely say that the mission was accomplished!

Cardiff – and the National Museum Wales – was an excellent venue for “polychaetologists” from all over the globe.

Snapshots of Cardiff

Snapshots of Cardiff (photos: K.Kongshavn)

In all we were 190 attendees from about 30 countries present – including a sizeable Norwegian group! Some of us (below) gave talks, and most were also involved in posters. Results and material from large projects and surveys such as PolyNor (Polychaete diversity in Nordic Seas), MAREANO (Marine AREA database for NOrwegian waters),  NorBOL (The Norwegian Barcode of Life), and MIWA (Marine Invertebrates of West Africa) were all well incorporated in the Norwegian contributions.

There were in fact a lot of contributions involving one or more collaborators from a Norwegian institution (UM, NTNU, NIVA, The SARS center, NHM Oslo, Akvaplan-NIVA ++) being presented during the conference. It is really nice to see that the community is growing through recruitment of both students and international researchers.

Norwegian delegates lining up in the City Hall before the start of the banquet

Norwegian delegates lining up in the City Hall before the start of the banquet

As Torkild said in his excellent blog post (in Norwegian, translation by me):

Pins marking where participants come from - this was not quite completed when the photo was taken, but none the less - we beat Sweden!

Pins marking where participants come from – this was not quite completed when the photo was taken, but none the less..well represented!

With so many active participants in the field, a lot of exciting research is being carried out in Norway. Not only do we have many projects – large and small – running at our institutions involving our “regular” Norwegian collaborators; there is also a significant proportion of international participation in these projects.

Furthermore, our activities enable researchers from all over the world to visit or loan from our scientific collections, and study the substantial (new) material that the projects are generating. It is nice to see that our efforts are being recognized in the international community! The recent flurry of activities has been well aided by the Norwegian Species Initiative (Artsprosjektet) (and the MIWA-project at UM).

The majority of our research is based on, or incorporates, museum material from our collections. The collections have been built over years, decades and even centuries, and continue to increase in scientific value as new science is added.

It is gratifying to see the material being used, and we hope it will gain even more attention in the aftermath of the conference.

From the poster session - these are some (!) of the posters we were involved in

From the poster session – these are some (!) of the posters we were involved in (photos: K.Kongshavn)

The University Museum was well represented, both in attendance, and in contributions. Below is a list of what we (co-)authored, presenting author is in bold, and University Museum people are in italics. We plan on posting some of the posters here, so stay tuned for that!


  • Giants vs pygmies: two strategies in the evolution of deep-sea quill worms (Onuphidae, Annelida)
    Nataliya Budaeva, Hannelore Paxton, Pedro Ribeiro, Pilar Haye, Dmitry Schepetov, Javier Sellanes, Endre Willassen
  • DNA barcoding contributing to new knowledge on diversity and distribution of Polychaeta (Annelida) in Norwegian and adjacent waters
    Torkild Bakken, Jon A. Kongsrud, Katrine Kongshavn, Eivind Oug, Tom Alvestad, Nataliya Budaeva, Arne Nygren, Endre Willassen
  • Diversity and phylogeny of Diopatra bristle worms (Onuphidae, Annelida) from West Africa
    Martin Hektoen, Nataliya Budaeva
  • Experiences after three years of automated DNA barcoding of Polychaeta
    Katrine Kongshavn, Jon Anders Kongsrud, Torkild Bakken, Tom Alvestad, Eivind Oug, Arne Nygren, Nataliya Budaeva, Endre Willassen


  • Diversity and species distributions of Glyceriformia in shelf areas off western Africa
    Lloyd Allotey, Akanbi Bamikole Williams, Jon Anders Kongsrud, Tom Alvestad, Katrine Kongshavn, Endre Willassen
  • Eclysippe Eliason, 1955 (Annelida, Ampharetidae) from the North Atlantic with the description of a new species from Norwegian waters
    Tom Alvestad, Jon Anders Kongsrud, Katrine Kongshavn
  • Phylogeny of Ampharetidae
    Mari Heggernes Eilertsen, Tom Alvestad, Hans Tore Rapp, Jon Anders Kongsrud
  • Ophelina (Polychaeta, Opheliidae) in Norwegian waters and adjacent areas – taxonomy, identification and species distributions
    Jon Anders Kongsrud, Eivind Oug, Torkild Bakken, Arne Nygren, Katrine Kongshavn
  • Pista Malmgren, 1866 (Terebellidae) from Norway and adjacent areas
    Mario H. Londoño-Mesa, Arne Nygren, Jon Anders Kongsrud
  • Lumbrineridae (Annelida, Polychaeta) from Norwegian and adjacent waters with the description of a new deep-water species of Abyssoninoe
    Eivind Oug, Katrine Kongshavn, Jon Anders Kongsrud
  • Nephtyidae (Polychaeta, Phyllodocida) of West African shelf areas
    Ascensão Ravara, Jon Anders Kongsrud, Tom Alvestad
  • Phylogeny of the family Maldanidae based on molecular data
    Morten Stokkan, Jon Anders Kongsrud, Endre Willassen

We had a mid-week excursion where we got to see a bit more of our hosting country; namely the impressive Caerphilly Castle constructed in the 13th century and still looking magnificent today, and a lovely lunch at the Llanerch wineyard with time for informal mingling and catching up.


Caerphilly Castle (photo: K.Kongshavn)

Note the red dragon in the Castle wall; this is the dragon of the Welsh flag. The story goes something like this (according to Wikipedia, at least!): From the Historia Brittonum,[2] written around 830 a text describes a struggle between two serpents deep underground, which prevents King Vortigern from building a stronghold. This story was later adapted into a prophecy made by the wizard Myrddin (or Merlin) of a long fight between a red dragon and a white dragon. According to the prophecy, the white dragon, representing the Saxons, would at first dominate but eventually the red dragon, symbolising the Britons, would be victorious.

Being museum people (er..? People employed at a museum, I mean!) ourselves, we made sure to visit the exhibitions as well, and especially the new “Wriggle!” exhibition, which is all about..worms! Lots of fun, and a*a lot* of information packed in. Make sure to visit it, if you get the chance!

Visiting the "Wriggle!" exhibition during the Ice Breaker event

Visiting the “Wriggle!” exhibition during the Ice Breaker event

The attendants have also been busy on Twitter, visit @IPC2016 or check #IPC12Cardiff for loads of photos and on-the-spot-commentaries

Finally, we would like to extend our heartfelt thanks to the arranging committeeDIOLCH!

Cheers, Katrine

ps: Dw i’n hoffi mwydod!

Travelogue from Jenni’s field-trip to California Academy of Sciences, San Francisco

Sea slugs and San Francisco

Phanerophthalmus sp. from Mozambique. Photo: Manuel A. E. Malaquias

Phanerophthalmus sp. from Mozambique. Photo: Manuel A. E. Malaquias

I am three months into the second year of my masters in marine biology, and was lucky enough to start off this semester with a three week trip to San Francisco in order to collect material for my project.

I am writing my master thesis for the University museum of Bergen on the phylogenetic systematics and evolution of a small marine gastropod.

The title of my project is “Patterns of speciation in the Indo-West Pacific, with a systematic review of the genus Phanerophthalmus (Cephalaspidea, Haminoeidae).

I will be using an integrative taxonomic approach combining fine-scale anatomical dissections and molecular phylogenetics to revise the taxonomy and be able to better understand the relationships of the species. The group is restricted to the shallow waters of the Indo-West Pacific and may therefore be used as a good model to study speciation and the historical biogeography of other organisms in this region.

In order to obtain specimens for this project loans have been made from various museums and academic institutions around the world. In total I have 60 specimens on loan from these various institutions, however they still only represent part of the diversity of the genus with limited geographical coverage. The California Academy of Sciences (CAS) in San Francisco holds the largest collection of sea slugs in the World, including specimens of the genus Phanerophthalmus, with over 100 specimens. So, it was arranged for me to visit this large collection and assess what was important for my project. Travelling to CAS also meant I was able to work alongside Dr. Terry Gosliner, a leading expert in the field of malacology.

Phanerophthalmus crawling on seagrass

Phanerophthalmus crawling on seagrass

Pier 39 and California sea lions

Pier 39 and California sea lions

So, on January 16th I got on a 10 hour flight to San Francisco. I stayed at a guest house in the Richmond district of San Francisco, about 40 min walk or 30 min bus from CAS.

Waking up on Sunday morning I was a bit jetlagged, but super excited to be in San Francisco. As it was Martin Luther King Jr. day tomorrow (Monday), I had two days to recover from the flight and adjust to the time difference (9 hours behind Bergen!).

I decided to go and explore the city so I took a bus to downtown San Francisco and went to Fisherman’s Wharf, to Pier 39 where the Aquarium of the bay is and also the California sea lions.

On Monday I went to see where I was going to be spending the next three weeks: at the California Academy of Sciences. Situated in Golden Gate park, the surroundings were beautiful.

Golden Gate park

Golden Gate park

Golden Gate Bridge

Golden Gate Bridge


After visiting the grounds of CAS I wandered over to the Golden Gate Bridge. There was rain in the air and the fog was coming down but the view of the bridge was spectacular.







California Academy of Sciences

California Academy of Sciences

Tuesday morning I arrived at CAS eager to dive into the collections. Terry met me at the staff entrance and after a chat and a coffee we got to work. The CAS database contained more than 100 specimens of Phanerophthalmus. The first few days were spent examining labels and matching live photos with specimens. The amount of material was a bit overwhelming and even though I would have liked to look at it all, this would not be possible during my short three week visit. So with guidance from my supervisor, Manuel Malaquias, I was able to focus on the most important specimens. As I am looking at the phylogeny of Phanerophthalmus it is important for me to have specimens which I can extract DNA from. It is also useful to know what these animals looked like live in order to maybe use the external morphology as a character for determining species.

The three weeks flew by so quickly. I spent my days with the collections, dissecting specimens and also got the opportunity to try the academy’s brand new scanning electron microscope. Terry was an amazing host and kept me busy. A huge thank you to him for dedicating so much time towards helping me out. Also, a huge thank you to everyone else at the academy for being so nice and welcoming. After my three weeks at CAS I had a few days to be a tourist in the city. My last weekend in the city happened to be Super Bowl 50 weekend and the city was buzzing with people and events. All in all I had a great visit, and now I have lots of material to carry on working with back in Bergen.

The collections (top), my dissection station (bottom left) and the male reproductive of Phanerophthalmus

The collections (top), my dissection station (bottom left) and the male reproductive of Phanerophthalmus

Scanning electron microscope session with Terry

Scanning electron microscope session with Terry



The amazing redwood trees at Muir Woods just outside the city

The amazing redwood trees at Muir Woods just outside the city

Keep calm and focus on sea slugs

Keep calm and focus on sea slugs


Door #16: First molecular-based phylogeny of onuphid bristle worms

Onuphidae are marine bristle worms with very rich external morphology and outstanding diversity of life styles within a single polychaete family. Onuphids can be very abundant in some marine biotopes, modifying the environment by their complex ornamented tubes and influencing the structure of benthic communities. They are very widely spread in the ocean inhabiting various biotopes from the intertidal zone down to hadal depths. Onuphids are widely harvested as bait sustaining local fisheries in southeastern Australia, Mediterranean and Portuguese coasts and are even commercially farmed with the full reproductive cycle from fertilization till fully-grown worms (up to 30 cm in length) in aquaculture facility.

Nothria otsuchiensis - a bristle worm from NSW, Australia (author N. Budaeva)

Nothria otsuchiensis – a bristle worm from NSW, Australia (author N. Budaeva)

The system of Onuphidae with 23 genera grouped into two subfamilies has been suggested by Hannelore Paxton (1986) and has been widely accepted since then. The first phylogeny based on the analysis of the combination of 16S rDNA and 18S rDNA genes has been recently published in Molecular Phylogenetics and Evolution. None of the subfamilies or tested genera appeared to be para- or polyphyletic showing a strong congruence between the traditional morphology-based systematics of the family and the newly obtained molecular-based phylogenetic reconstruction. However the previously suggested hypotheses on intrageneraic relationships within onuphidae were largely rejected.

Phylogenetic tree of a bristle worm family Onuphidae (Budaeva et al., 2016)

Phylogenetic tree of a bristle worm family Onuphidae (Budaeva et al., 2016)

Suggested reading:

Budaeva N., Schepetov D., Zanol J., Neretina T., Willassen E. 2016. When molecules support morphology: Phylogenetic reconstruction of the family Onuphidae (Eunicida, Annelida) based on 16S rDNA and 18S rDNA. Molecular Phylogenetics and Evolution 94(B): 791–801.

Paxton, H., 1986. Generic revision and relationships of the family Onuphidae (Annelida: Polychaeta). Records of the Australian Museum 38, 1–74.

Aquabait Marine Worm Aquaculture:

Nataliya Budaeva’s web page:


Door #13: Time for rejuvenation

Some of the fundamental existential impacts of the solar cycle were certainly understood by the Neolithic people who built Newgrange and were able to align the gigantic construction with the position of the sun rise at winter solstice. It was a point of return in “the wheel of time”, the annual cycle of “ageing, rebirth, and rejuvenation of Nature”. But how living individuals reproduce and come into being was a mystery right up to modern times. The Roman writer in natural history, Pliny (ca 70 AD), for instance stated that: “…after six months’ duration , frogs melt away into slime, though no one ever sees how it is done; after which they come to life again in the water during the spring, just as they were before. This is affected by some occult operation of Nature, and happens regularly every year. Mussels, also, and scallops are produced in the sand by the spontaneous operations of nature.”

Although the famous experiments by Francesco Redi had refuted some ideas about “spontaneous generation” in the mid 16-hundreds, the concept was still an important part of Lamarck’s theory of evolution that was opposed by his colleague Cuvier. Birth, of course, has also been a subject of discussions when pondering the mysteries of the Mary cult: was it really a case of parthenogenesis? What is really going on in the making of a body – the “process of incarnation”?


Botryllus schlosseri (photo: K. Kongshavn)

Botryllus schlosseri, the “golden star tunicate”, is a common species on Atlantic coasts and recently has expanded its distributions to other seas as a result of human marine travelling. Researchers at the University of Bergen (Delsuc et al 2006) found that the tunicates belong to an evolutionary lineage that is the closest to vertebrates (including humans). B. schlosseri is relatively easy to keep in aquaria and has taught us a lot about reproduction and life cycles.

The similarity between the tunicates and the vertebrates are only apparent in the early stages of tunicate life. The larvae have a body with a tail containing the “chorda”, and a dorsal nerve tube, – both unique characteristic features of the Chordate animals (see figure 1A in in Voskoboynik el al. 2013). But these similarities disappear within a few hours when the free swimming larva has settled on some surface substrate and started the metamorphosis into the sack like body of an adult tunicate with a filter feeding gut. The larva was the result of sexual reproduction, the merged genetic material from sperm and egg. However, the metamorphosed individual will soon begin to reproduce asexually by budding off a copy of itself in a neighbouring position. The results of such multiplications are clusters of two to 12 genetically identical individuals in a star like pattern. These individuals, called zooids, are active for relatively short time, about a week at 19 oC, until they become inactive and gradually are reabsorbed by other cells in the colony while being replaced by new zooids. This sort of programmed cell death is called apoptosis and researches believe that studies of B. schlosseri can reveal some of what is going on with ageing and death of cells. It has been estimated that in an adult human body there is apoptosis of about 50 to 70 billion cells per day. Fortunately there is also renewal of cells, like in the growing colony of Botryllus. Very interesting things may happen if the zooids from different larvae are meeting up at the margins of two colonies with the so-called ampullae. Botryllus has a self-recognition system that is controlled by just one gene, but the gene occurs in many variants (alleles). If the alleles from two colonies are compatible, the blood vessel systems of the two colonies may grow together so that one colony is actually formed by zooids with different genetics. This is somewhat analogous to what happens between mother and child in the mammalian placenta. If the compatibility of two colonies is bad, they will “fight” each other in an inflammatory immune reaction. Such processes have special interest with respect to understanding immune systems and the outcome of organ transplantation.

It takes about 3-4 weeks for a colony to become sexually mature so that egg and sperm may be released in turn, avoiding self-fertilization. The duration of a colony is believed to be about 12 to 18 months in Norwegian waters (Moen & Svendsen 2008).

The reproduction system of B. schlosseri is just one of many different reproduction systems of animals. Where does individuality begin and stop? Would a zooid greet its neighbour with “Merry Christmas, I!”?

Suggested reading:

Delsuc et al. (2006). Tunicates and not cephalochordates are the closest living relatives of vertebrates. Nature: 439:965-968.

Manni et al (2007). Botryllus schlosseri: A model ascidian for the study of asexual reproduction. Developmental Dynamics 236(2): 335-352.

Moen & Svendsen (2008) Dyreliv i havet. KOM Forlag.

Tiozzo et al. (2006). Programmed cell death in vegetative development: Apoptosis during the colonial life cycle of the ascidian Botryllus schlosseri. Tissue and Cell 38 (3): 193-201

Voskoboynik et al. (2013) The genome sequence of the colonial chordate, Botryllus schlosseri Elife. DOI: 10.7554/eLife.00569.001


Door #11: Just a white blob?

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

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

Colobocephalus costellatus M. Sars, 1870. Photo: Lena Ohnheiser, CC-BY-SA. Also featured on

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)

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!"

*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:

Colpodaspis pusilla:

Philinoglossa helgolandica:

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.

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