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The Invertebrate Collections is one of the University Museum’s large collections of scientific zoological material. “Invertebrates” is a traditional grouping for animals without a backbone. At our museum, like in many other scientific collections, invertebrates is the remaining part of the animal kingdom when vertebrates, insects, spiders and millipedes (entomology) have been accounted for. Invertebrates therefore is a diverse group of very different animals with often spectacular ways of life in many types of environments. We still know very little about many species of invertebrates because they are difficult to study and identify. Many species are also still undiscovered. Scientific collections are fundamental sources of knowledge about our zoological diversity. On these pages we want to inform about the contents of the collections and about past and current activities.

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Door #11 Invertebrately inspired art?

Scientific illustrations today are usually formed within quite strict limits. We use photographs or drawings of small details, and these are all connected to one specific specimen that preferably is to be found in a scientific collection.

But can other approaches also help us? The artist Pippip Ferner has long found her inspiration in nature, and especially the (marine) invertebrates. Maybe her pictures can inspire us to examine other details in our study-animals? Maybe a picture can inspire you to think more about nature, the sea, or invertebrates – their lives and lores? These are not pictures that are meant to be scientifically accurate, but rather fabulations inspired by the wild things that happen when evolution gets to do as it pleases…

Some of Pippis drawings are inspired from scientific drawings, both old and new, some are from animals we have looked at together.

Here are some of Pippips pictures from this year, and the animals that inspired them. These three pictures were chosen to be part of the Evolution and Art section of the international science conference Evolution this summer in Austin, TX.

"Tunicate anatomy" (c) Pippip Ferner

“Tunicate anatomy” (c) Pippip Ferner

Pippip says about this first picture:

“A scientific illustration of a TUNICATE is the inspiration for this work. Tunicates are sort of last stage before vertebrates. Clues for this is found in the larva that has a notochord, comparable to the spine of vertebrates. It has cerebral vesicle equivalent to a vertebrate’s brain, sensory organs that includes an eyespot to detect light and an otolith, which helps the animal orient to the gravity.
Fascinated by the thought of this “slimy blob” having many features similar to humans resulted in this quite complex outcome. The overload of insistent lines has given the tunicate quite a sophisticated system.”

Komodo National Park sea squirt (Polycarpa aurata). Photo: Nick Hobgood (wikipedia)

Komodo National Park sea squirt (Polycarpa aurata). Photo: Nick Hobgood (wikipedia)

On the left is a photo of a live tunicate. This photo is from Indonesia, but tunicates are common to find also in our colder waters. They can be solitary as this one, or colonial – where several tunicates form a colony together by budding, so that one large colony basically has the exact same DNA. Most tunicates are sessile (they sit attached to one place), but some live floating around in the water. The best known of these pelagic tunicates are the salps of the southern oceans.

 

Internal anatomy of a tunicate (Urochordata). Adapted, with permission, from an outline drawing available on BIODIDAC. (Wikipedia)

Internal anatomy of a tunicate (Urochordata). Adapted, with permission, from an outline drawing available on BIODIDAC. (Wikipedia)

A scientific illustration of a tunicate in a Biology textbook will look something like this:

 

 

 

 

 

 

Moving to other invertebrates, Pippip has worked with clams:

"Bivalve anatomy" (c) Pippip Ferner

“Bivalve anatomy” (c) Pippip Ferner

“In this image I question how the clam lives in symbiosis with other species as its shell gets weaker due to climate changes. The drawing might resemble the results of some kind of scientific inquiry with references to the anatomy of a clam (bivalve).
In my work I let my own artistic evolutionary process make the clam into something more abstract.”

(If you wait until door # 22, there might be a story that relates to bivalves that live with others…)

This is a Ctenophore, a comb jelly:

"Comb jelly anatomy" (c) Pippip Ferner

“Comb jelly anatomy” (c) Pippip Ferner

“The starting point of this work was a detailed illustration from biologist Ernst Haeckel’s (Artforms in Nature) of a comb jelly/ctenophorae. The comb jelly differs from other jellyfish with more sophisticated nervous system with both synapses and individual muscle cells.
The outcome of this drawing is a tribute to the beauty of the structure of this organism.”

Jelly fishes anf Comb jelly fishes. Illustration: Ernst Haeckel, Kunstformen der Natur 1904, plate 27

Jelly fishes anf Comb jelly fishes. Illustration: Ernst Haeckel, Kunstformen der Natur 1904, plate 27

Ctenophores are predatory planktonic jellies. The special thing about them, according to our Jelly-specialist Aino, is that they have a rotational symmetry. The diagnostic feature of comb jellies are their comb-rows that they use for swimming. The photos above represent the three groups of comb jellies – all of them are present in Norway.

 

To the right is the Haeckel-picture she started from, and here is a film of Comb jellies from the Chicago Shedd Aquarium.

 

 

 

Pippip, Anne Helene and Aino

 

 

Door #10: Siphonophores

Today, I thought I’d introduce to you to a cool group of animals that is ubiquitous in the oceans (including the Norwegian seas), but unfamiliar to most people. Siphonophores (“kolonimaneter” in Norwegian) belong to cnidarians, a group that includes corals, anemones, hydroids and jellyfish, and is characterized by the presence of stinging cells used in prey capture. All siphonophores are predatory, and use their stinging tentacles to catch small crustaceans or, in the case of some species, even small fish.

The most (or only) familiar siphonophore for the majority of people is probably the highly venomous Portuguese Man O’War (Physalia physalis), which can be spotted floating on the surface of the ocean or stranded on beaches. However, it is not really representative of the group as a whole, as most siphonophores live in the water column of the open ocean rather than its surface. There are around 200 described species of siphonophores.

The most fascinating feature of siphonophores is their peculiar body plan. While siphonophores may appear to be a single animal, they are in fact a colony of physiologically connected and genetically identical but morphologically diverse individuals called zooids that have specialized to carry out different tasks for the colony. Siphonophores belong to the class Hydrozoa (“polyppdyr” in Norwegian), which covers two basic body plans: the polyp/hydroid and the medusa.

Schematic of a physonect siphonophore. From http://www.siphonophores.org (CC-by-nc-sa)

Schematic of a physonect siphonophore. From http://www.siphonophores.org (CC-by-nc-sa)

The various zooids comprising a siphonophore colony can also be divided into these main groups. For example, the zooids used for swimming, called nectophores, are medusoid, while the feeding zooids, or gastrozooids, are polyp-like. The siphonophore colony can also include specialized defensive, protective and reproductive zooids. All the zooids forming a colony arise by budding from a single fertilized egg. The different zooids are specialized to the degree that they cannot function as individual animals any more, and are only able to perform their specific tasks as parts of the siphonophore colony.

Anterior nectophore, posterior nectophore and eudoxid of the calycophoran siphonophore Dimophyes arctica – a common species in Norwegian waters. Photos by Aino Hosia (cc-by-sa)

Anterior nectophore, posterior nectophore and eudoxid of the calycophoran siphonophore Dimophyes arctica – a common species in Norwegian waters. Photos by Aino Hosia (cc-by-sa)

The zooids, for example the swimming nectophores, vary in appearance between species, and can be used for species identification. In addition, the various types of zooids in the colony are arranged in a strict species specific pattern, providing the intact colonies of each species with their particular appearance. While the individual zooids are generally small, millimeters to centimeters in size, some siphonophore species, like Praya dubia, may have colonies that reach 40 m in length! Siphonophore colonies generally have a zone of one or more (up to several dozen) swimming nectophores at the front, used to pull the colony through water. Behind this nectosome is the siphosome, which contains the feeding, reproductive and other zooids in a repeating pattern, each iteration of which is called a cormidium. In some species (suborder Calycophorae), these cormidia are released as small free-living reproductive colonies called eudoxids. Unfortunately, siphonophore colonies are extremely fragile and tend to fall apart during standard plankton sampling with nets, leaving behind a bewildering array of small bits and pieces – part of the reason they are relatively poorly known to most people.

Colony of physonect siphonophore Physophora hydrostatica, aka hula skirt siphonophore. Photo by Aino Hosia (cc-by-sa)

Colony of physonect siphonophore Physophora hydrostatica, aka hula skirt siphonophore. Photo by Aino Hosia (cc-by-sa)

Intact siphonophore colonies are beautiful, but often utterly alien in appearance. It is interesting to consider where to draw the line between an individual and a colony. While we as individuals have specialized organs to carry out our various bodily functions, siphonophore colonies are made up of specialized interdependent individuals or zooids similarly carrying out their specific tasks.

As part of project HYPNO we are charting the diversity of pelagic hydrozoans, including siphonophores, in Norway. There are ~15 species observed in Norwegian waters, and some, particularly Dimophyes arctica, Lensia conoidea and Nanomia sp. are extremely common components of marine plankton. However, siphonophores are primarily noticed when they become a nuisance: For example, mass occurrences of Muggiaea atlantica and Apolemia uvaria have in the past killed large numbers of farmed fish in Norway, with resulting losses to aquaculture companies.

– Aino (HYPNO)

Intrigued by siphonophores? For more information, visit e.g. http://www.siphonophores.org/  by Casey Dunn.

Door #9: Research stay of Juan Moles

Juan working at the Museum

Juan working at the Museum

During my stay at the University Museum of Bergen I have been working on the diversity and systematics of Antarctic philine snails. Most of the samples were collected during different cruises on board of the RV Polarstern in the Eastern Weddell Sea, Bouvet Island, and South Shetland Islands (West Antarctica). I photographed all specimens and then clipped them for the DNA analysis (see pictures).

 

 

 

 

 

I was able to work at the DNA lab with excellent resources for DNA extraction, amplification, purification, and sequencing.

I am indebted to Louise Lindblom who helped me at the beginning of my crusade there. After a first barcoding of all the material we identified six clades, from which we selected a maximum of three specimens to further sequence the ribosomal genes 16S and 28S and the nuclear gene codifying for the Histone 3.

The first phylogenetic tree with all partitions resulted in the finding of novel clades that now deserve further investigation.

Prof. Manuel António E. Malaquias and his PhD Student Trond Oskars helped me dissecting the material for anatomical analyses. Important taxonomical characters were those related to the male reproductive system, the digestive tract as well, and the shell. After the dissections and drawings of the main parts I prepared the hard structures such as the radula, the shell, and the gizzard plates for Scanning Electron Microscopy (SEM) as well as some soft structures after critical point drying. I could photograph all these material at the same facilities of the museum being helped by Irene and Katrine. After the two months of work, I ended up having huge amount of anatomical and molecular data that deserves further processing. See a picture of the radula and a gizzard plate:

Moreover, I was able to join the student diving club and make several dives to get to know the local flora and fauna. I could even collect some other heterobranch slugs for the barcoding project of the museum. See a couple of pictures of the nudibranch Limacia clavigera and Onchidoris muricata.

Overall, Bergen is a nice city to visit surrounded by nice mountains, good (but not cheap) beers, beautiful fjords, and nice people. I hope I can come back with a postdoctoral position to further enjoy the country and meet more Viking descendants.

-Juan

Door #8: the ups and downs of a marine werewolf?

When we think about what drives the ecosystems, much of the initial responsibility is put on the sunlight. This is mainly because of the photosynthesis, and thus the basic pieces of almost all food-webs, but light is also important for the animals. Many animals use visual cues to find food, and whether you search for food or do not want to become food, the presence (or absence) of light will help you.

Themisto sp swims up into the dark night. Photo: Geir Johnsen, NTNU

Themisto sp swims up into the dark night. Photo: Geir Johnsen, NTNU

Seawater is a pretty good stopper of light. We don’t need to dive far down before we are in what we consider a dark place, and less and less light finds its way the deeper we come. We tend to call the depths between 200 and 1000 m “the twilight zone”: most light stops way before 200m and the last straggling lumens give up at 1000m.

Most places on earth has a daily division between a dark and a light period: night and day. This is the ultimate reason for what is often called “the largest motion on earth”: Millions of zooplankton hide out in the darker parts of the water column during the day, and then move up to feed on the plants living in the light-affected parts of the water during the night (when predators will have a hard time seeing them). This daily commute up and down is called Diel Vertical Migration (DVM).

Themisto sp among the many smaller particles. (The light in this picture is from a flash). Photo: Geir Johnsen, NTNU

Themisto sp among the many smaller particles. (The light in this picture is from a flash). Photo: Geir Johnsen, NTNU

But what about the waters north of the polar circle? These areas will for some time during the winter have days when the sun stays under the horizon the entire day – this is “the Dark time” (Mørketid). At higher latitudes, there will be several days, or even weeks or months when the sun is so far below the horizon that not even the slightest sunset-glow is visible at any time. In this region, we have long thought that the Dark time must be a dead or dormant time.

 

The acoustic signals that gave the first indications of LVM. Figure 2 from Last et al 2016.

The acoustic signals that gave the first indications of LVM. Figure 2 from Last et al 2016.

We could not have been more wrong! It turns out that during the polar night, the DVM moves from being on a 24 hr cycle (sunlight-induced), to a 24.8 hour cycle! What is now the driver? The moon !(The lunar day is 24.8 hrs). Another thing that shows us that the moon must give strong enough light that predators can hunt by it, is that every 29.5 days most of the zooplankton sinks down to a depth of 50m: this falls together with the moon being full. Researchers have started to call this LVM (Lunar-day Vertical Migration) to show the difference to the “normal” DVM. There are of course lots of complicated details such as the moons altitude above the horizon and its phase that influences the LVM, but in general we can say that during the polar night (the Very Dark time), the “day” as decided by light has become slightly longer than normal.

The full moon, photographed by the Apollo 11 crew after their visit. Photo: NASA, 1969

The full moon, photographed by the Apollo 11 crew after their visit. Photo: NASA, 1969

Themisto - the werewolf. Note that the whole head is dominated by eyes - this is a visual hunter! Photo: Geir Johnsen, NTNU

Themisto – the werewolf. Note that the whole head is dominated by eyes – this is a visual hunter! Photo: Geir Johnsen, NTNU

Some of the larger animals taking part in the LVM are the amphipods Themisto abyssorum and Themisto libellula. They are hunters – so their reason to migrate up in the water column is not the plants, but the animals eating the plants; their favourite food are copepods of the genus Calanus. These are nice and quite energy-rich small crustaceans that eat the microscopic plants in the upper water column. We have sampled both Themisto-species in the middle of the winter (january), and their guts were filled to the brim with Calanus, so we know that they continue hunting by moon-light. They are such voracious hunters that some researchers have started to call them marine werewolves: the moonlight transforms them from sedate crustaceans to scary killers…

 

But, if they are the hunters, why do they spend so much time in the deep and dark during the lighter parts of the day? The hunters are of course also hunted. Fish such as polar cod (Boreogadus saida),  birds such as little auk (Alle alle) and various seals like to have their fill of the Themisto species. So – life has its ups and downs, and the dance of hunter and hunted continues into the dark polar night…

Anne Helene


Literature:

Berge J, Cottier F, Last KS et al (2009) Diel vertical migration of Arctic zooplankton during the polar night. Biology Letters 5, 69-72.

Berge J, Renaud PE, Darnis G et al (2015) In the dark: A review of ecosystem processes during the Arctic polar night. Progress in Oceanography 139, 258-271.

Kintisch E (2016)  Voyage into darkness. Science 351, 1254-1257

Kraft A, Berge J, Varpe Ø, Falk-Petersen S (2013) Feeding in Arctic darkness: mid-winter diet of the pelagic amphipods Themisto abyssorum and T. libellula. Marine Biology 160, 241-248.

Last KS, Hobbs L, Berge J, Brierley AS, Cottier F (2016) Moonlight Drives Ocean-Scale Mass Vertical Migration of Zooplankton during the Arctic Winter. Current Biology 26, 244-251.

Door # 7: Always on my mind…?

Today is #WormWednesday on Twitter, and we figured that it was a good day to introduce you to this rather unlucky fellow and his sidekick…

The orange (coloured in Photoshop) is the parasite. The two long sacks are filled with eggs.

The orange part (coloured in Photoshop) is the parasite. The two long sacks are filled with eggs.

They were collected during our field work in Sletvik in October. The worm is a polychaete in the genus Terebellides, whilst the parasite is a Copepod. This species rich group of small crustaceans have many modes of life, but parasitism is a common one, with about half of the ~13 000 species being parasites.

headache2_zerene HEADACHE3

Door # 6: Stuffed Syllid

Todays calendar critter is a Trypanosyllis sp. – a undescribed species from the genera Trypanosyllis in the family Syllidae. It most closely resembles a species described from the Mediterranean Sea. The Norwegian species is common in coral rubble, and has been assumed to be the same species as the one described from the Mediterranean. Genetic work reveals that these two are in fact separate species, and thus the Norwegian one is a new species awaiting formal description and naming. (If you read Norwegian, you can learn more about how species are described and named here: Slik gir vi navn til nye arter).

A new species of Trypanosyllis, collected in Sletvik, Norway. Photo by Arne Nygren. CC-by-sa

A new species of Trypanosyllis, collected in Sletvik, Norway. Photo by Arne Nygren. CC-by-sa

This specimen was collected, identified and photographed by Arne Nygren during our field work in Sletvik as part of his work on cryptic polychate species in Norway.

Syllids have opted for a rather fascinating way of ensuring high fertilization rates; something called epitoky: they asexually produce a special individual – the epitokous individual – from their bodies, and release this to go swimming in search of a mate. In the photo you can see that the female reproductive body (epitoke) is filled with orange eggs and has its own set of eyes, close to the middle of the animal. This section will break away from the mother animal and swim away in search of a male reproductive body to reproduce with. The mother animal will then grow a new female reproductive body.

-Arne & Katrine

Door #5: A visit from Mario

The collections have many guest researchers come here to work on our material, and one of our most frequent guests of lately has been Mario, who makes the long trip from Colombia to study both the West African material that we have from the MIWA-project, and to work on Nordic material. We asked him to make a contribution to the blog, and got the folllowing:

Mario in the Lab

Mario in the lab

For October – November visit.

For my third time in the Museum, I have found, as always, very good company from my colleagues in the lab: Katrine, Nataliya, Jon and Tom. Deep morphology and molecular method discussions over very good coffee were the “breaks” between periods of hard work at the microscope.

This time, I take to my home two papers close to completion; one about species of the genus Pista (Terebellidae) with additional information to what I found during my last visit in January. The second paper is about species in the subfamily Polycirrinae (Terebellide) from the West coast of Africa.

The idea is combine drawings, digital photos of specimens with methyl-green staining pattern and SEM pictures, as well as molecular information that will hopefully help us separate species and make better estimates of the region’s biodiversity.

Field work - somewhat cold and windy

Field work – somewhat cold and windy

 

The visit – which was without snow and with only a few showers of rain in Bergen (!), though with some very cold and windy moments at the Marine Station of the University of Trondheim – and sharing time with recognized polychaetologist as Fred Pleijel, Torkild Bakken, Eivind Oug, and Arne Nygren, was as spectacular as to know the Aurora Borealis.

Aurora borealis and a hooded tropical visitor. Photo: K.Kongshavn

Aurora borealis and a (hooded) tropical visitor. Photo: K.Kongshavn

 

Door #4: A spindly Sunday

One of the cool things with the NorBOL-project is that it allows us spotlight animal groups that we don’t normally get to do much with. One such group is the sea spiders, or Pycnogonida. These spider-like critters wander around on the seafloor looking for other invertebrates to snack on (some also live on detritus and algae), and (presumably) for love. I certainly find a lot of them carrying egg sacks and young ones, so they must succeed every now and then! In the Pycnogonida, it is the males who care for the laid eggs and the young, rolling the eggs into one or several balls that he carries around on his ovigers.

The ones I photographed ranged from tiny to over 30 cm:

Colossendeis angusta, collected by MAREANO - this is bigger than a handful

Colossendeis angusta, collected by MAREANO – this is bigger than a handful

Ammothea echinata from the day when we joined the local student dive club - the animal is only a few mm

Ammothea echinata from the day when we joined the local student dive club – the animal is only a few mm

Anatomy of a pycnogonid: A: head; B: thorax; C: abdomen 1: proboscis; 2: chelifores; 3: palps; 4: ovigers; 5: egg sacs; 6a–6d: four pairs of legs Sars, G. O. (1895). An account of the Crustacea of Norway, with short descriptions and figures of all the species. Christiania, Copenhagen, A. Cammermeyer. L. Fdez (LP) – digitization and colouration. - Own work External anatomy of Nymphon sea spider. After G. O. Sars (1895).

Anatomy of a pycnogonid: A: head; B: thorax; C: abdomen 1: proboscis; 2: chelifores; 3: palps; 4: ovigers; 5: egg sacs; 6a–6d: four pairs of legs  L. Fdez (LP) – digitization and colouration. – Own work based on External anatomy of Nymphon sea spider. After G. O. Sars (1895).

At first glance they look a lot like the spiders we find on land, but they are really a very different class of animals (literally!); The sea spiders are found within  Checked: verified by a taxonomic editorAnimalia (Kingdom) > Checked: verified by a taxonomic editorArthropoda (Phylum) > Checked: verified by a taxonomic editorChelicerata (Subphylum) > Checked: verified by a taxonomic editorPycnogonida (Class) (from WoRMS), whilst “land spiders” are found within the order Aranea in the class Arachnida.

Extant memebers of the Pycnogonidae are found within the order Pantopoda, which translates into “all legs”, which describes them quite well! They have even moved most of their internal organs (of which they have rather few; respiration is done across the body surface, so no gills) into the legs.

The more I look at them, the funnier they look – but that may be in the eye of the beholder, as a few arachnophobes passing by the camera have declared loudly that there is nothing charming to find here – I beg to disagree!

Goofy looking Nymphon stroemi (note the cheliphores/claws)

Goofy looking Nymphon stroemi (note the chelipores/claws) and the eyes on a tubercle on the head – they have eyes facing both forwards and backwards

Pycnogonum litorale

Pycnogonum litorale

Some species, like this Nymphon gracile, can also swim: "...the swimming motions are the same as those used in walking, but more vigorously executed" King 1974

Some species, like this Nymphon gracile, can also swim: “…the swimming motions are the same as those used in walking, but more vigorously executed” King 1974

Nymphon hirtipes with hitchikers

Nymphon hirtipes with hitchikers

ZMBN_104970

Pseudopallene circularis from Spitsbergen

They are usually slow movers: Hover over the image to see a pycnogonid walking on the sea floor

To fill a plate with tissue samples from 95 specimens (1 animal = 1 specimen) of pycnogonida doesn’t sound too complicated, does it? Well, it turned out to be a bit of an adventure to gather enough animals that had been preserved in such a way that we could get DNA out of them (older material is usually fixated in Formaldehyde, which makes it unsuited for genetic work), and that was identified (had a name to them). Since we are in the process of building up the national (and international) reference library (the BOLD database) that the short DNA-segments (the “barcodes”) are to be matched up to later when someone wants to know which species “Animal X” belongs to, we need to know which species we are submitting for sequencing.

Our collection of barcode-compatible identified pycnogonids received a welcome boost when the shipment of processed material (identified, and measured for biomass) from MAREANO‘s beamtrals collected in 2013 arrived, as these had been fixated in ethanol – and identified by researchers who have worked extensively with the group.

Even so, I couldn’t fill a whole plate with only those specimens. Thankfully, I have skilled collegues that were able to put species names to almost all of the critters I could hunt down in our collections, and so now we have 95 animals ready from 26 different species! We also have some bona fide mysteries that we hope the BOLD-database will help us solve as well; animals that does not comply with any of the identification keys…!

Fingers crossed for a very successful sequence run and a lot of new information about  the Pycnogonida of Norway!

Pseudopallene longicollis, collected by MAREANO

Pseudopallene longicollis, collected by MAREANO

Info:
King, P.E. 1974: British Sea Spiders, synopses of the British Fauna (New Series) No. 5

Door #3: a week in the field

We spent a lovely week in October collecting animals at the field station of NTNU in Agdenes in central Norway.

About 15 researchers and collection curators were gathered for a week of sampling with gear ranging from grabs and trawls deployed from the research vessel Gunnerus to buckets and shovels on the beach. As you may be able to tell, a good time was had by all!

Sletvik_collage

The field work was arranged by the our colleagues at NTNU University Museum, and served multiple purposes:

  • We collected ultra-fresh material for barcoding through the norwegian Barcode of Live project (NorBOL) – several plates were initiated during the week and then brought back to Bergen where we will continue filling them with material from our collections – each plate needs to be filled with 95 samples that can be run with the same primer, so we need to select our material carefully.
  • The marine collections of NTNU got a substantial boost
  • Fresh material was collected for teaching faunistics
  • Photodocumenting live specimens (we have some fantastic polychaete photos from this coming up later in our calendar)
  • Four Norwegian Species Initiative funded projects were participating, collecting material for their projects – as were people from the EU-project SponGES.
  • We at UM also relished the chance to sample in the littoral zone, which is a undersampled habitat in our collections

We are working on the material now, and some of it is scheduled to make an apperance on the blog over the next couple of weeks – so stay tuned!

Door #2: The head of the Medusa

Medusa_by_Carvaggio

Medusa by Carvaggio (Wikimedia)

Today we go mythological, and visit the Greek pantheon.

Medusa was one of three Gorgon sisters who all had snakes for hair according to the mythology – and one can certainly understand how the British zoologist Leach (1791-1836) came to think of the name when he formally described the genus Gorgonocephalus (Literally ” Gorgon’s head”) in 1815. They are found within the echinoderm class of Ophiuroidea (brittle stars).

In English they are known as basket stars, whilst Norwegians know them as “Medusahode” – head of the Medusa.

The English name refers to how they feed: basket stars are predators, and raise their bifurcated arms covered with tiny hooks, spines and grooves up into the current forming a basket to sift and entrap plankton and other small critters from the water as it streams past – then they use their arm branches (possibly aided by the tube feet) to guide the trapped food to their mouths, which is on the underside (like in starfish).

Gorgonocephalus lamarcki, photo by K.Kongshavn

Gorgonocephalus lamarcki, photo by K.Kongshavn

kart

This specimen was collected in Svalbard in 2009 (way up at 80ºN) during a student course at UNIS, and has been barcoded through the Norwegian Barcode of Life (NorBOL) project.

 

Hover your cursor over the image below to see a basket star move

-Katrine