Category Archives: Norwegian Taxonomy Initiative

Guest Researcher: Joan

Dr Joan Soto from the University of Valencia (Spain), visited us at the museum during August/September 2017 to collaborate with HYPNO on the mysterious issue of linking hydroids and their medusae. We asked him about his experience, and got the following:

Joan, ready to go jelly-hunting under the blue sky!

Joan, ready to go jelly-hunting under the blue sky!

Imagine a caterpillar and its butterfly described as different species by the scientific community. Now think on how confusing it would be if everybody kept calling them with different names over centuries. Well, this is the case of many hydroids and their corresponding medusae!

Hydrozoans, together with other well-known animals such as corals, anemones and jellyfishes, are included within the Phylum Cnidaria. Most hydrozoans are metagenetic, which means that they alternate between asexual (the polyp, usually benthic) and sexual (medusae, usually pelagic) stages in their life. Since the early works by Linnaeus in the mid-18th century, the very first scientists who showed interest in hydrozoans specialized primarily in a single stage of their life cycle, often neglecting the other, and even those courageous scientists who accepted the challenge of studying both groups were unable to discover the correspondence between such different animals as the polyp and the medusa.

Nowadays, in the era of molecular tools, new techniques are revealing that things are not what they seem, neither do they look like what they really are. Thanks to project HYPNO, several links between polyps and medusae have been found, with the subsequent adjustment in their ID (a.k.a. their scientific name), but that is not all! New evidences are bringing to light that some hydrozoans, even if they are morphologically identical to each other, in reality belong to different species, a fact known as “cryptic species”.

Both of these phenomena may be involved in the taxonomic confusion surrounding the hydroid Stegopoma plicatile and the medusa Ptychogena crocea, the former a worldwide reported species, the latter a Norwegian endemism. How can a medusa be so restricted in distribution while its hydroid lives everywhere? Perhaps now we know the answer thanks to molecular tools: Stegopoma plicatile may represent a complex of species, hiding a misunderstood diversity, and similar S. plicatile hydroids may produce different Ptychogena medusae. In other words, perhaps the polyp does not have such a wide distribution, and records from other parts of the world should be re-examined in detail, paying special attention to the tiniest and easily overlooked details of its morphology. But of course this is a job only for very patient detectives…

Hydroids of Stegopoma plicatile (like this one) from all over the world look very similar to each other, but may produce very different medusae.

Hydroids of Stegopoma plicatile (like this one) from all over the world look very similar to each other, but may produce very different medusae.

These beautiful medusae of Ptychogena crocea collected in Korsfjord were sexually mature. You can see the four gonads as folded masses of yellow tissue in each jellyfish.

These beautiful medusae of Ptychogena crocea collected in Korsfjord were sexually mature. You can see the four gonads as folded masses of yellow tissue in each jellyfish.

Thus, this was the objective of my recent visit to the Bergen University Museum. An outstanding month surrounded by enthusiastic scientists, amazing landscapes, restricted doses of sun, and upcoming challenges: we trust that current and future analyses combining both molecular and morphological taxonomy will lead to settle the correspondence of Stegopoma hydroids with other Ptychogena-like medusae from all over the globe, or even to the description of new species to science!

Deploying the net with help of the crew from RV "Hans Brattstrøm"

Deploying the net with help of the crew from RV “Hans Brattstrøm”

Team-work during the sampling makes everything a lot easier!

Team-work during the sampling makes everything a lot easier!

The amazing crane of the RV "Hans Brattstrøm" allowed us to efficiently hunt for jellyfish at the fjords.

The amazing crane of the RV “Hans Brattstrøm” allowed us to efficiently hunt for jellyfish at the fjords.

This is what our samples look like when we finally get to look at them on board

This is what our samples look like when we finally get to look at them on board

-Joan

Getting back in business

The blog has been quiet over summer – but we’ve been busy!

The #AnnelidaCourse2017 came to an end, and happy participants went back to their home institutions with a lot of new knowledge, a increased contact network, and many new friends.

a)Students working in the lab; b) Picking interesting animals from the samples onboard R/V Hans Brattström; c) Animals to be studied; d) Group photo of most of the participants; e) Detailed study and drawing of a specimen; f) Field work onboard R/V Aurelia Fotos: K.Kongshavn (a,b,e), G. Kolbasova (c), G.Jolly (d), S. Rosli (f)

a) Students working in the lab; b) Picking interesting animals from the samples onboard R/V Hans Brattström;
c) Animals to be studied; d) Group photo of most of the participants; e) Detailed study and drawing of a specimen; f) Field work onboard R/V Aurelia Fotos: K.Kongshavn (a,b,e), G. Kolbasova (c), G.Jolly (d), S. Rosli (f)

Heaps (HEAPS!) of samples have been cataloged and labeled, DNA-sequencing has completed on the shipment we sent in June and we’re working on analyzing the results, and samples from the cruises we particpated on have and are being sorted.

The next shipment of animals to be barcoded through NorBOL is being assembled – of marine invertebrates from our collections, one plate of polychaetes and one plate of isopods have been prepared, and we plan on completing a few more plates before shipping in October.

Isopods for barcoding - these have all been collected and identified by the MAREANO project. Photo: K.Kongshavn

Isopods for barcoding – these have all been collected and identified by the MAREANO project. Photo: K.Kongshavn

We will also get contributions from several of the Norwegian Taxonomy Initiative projects (Artsprosjekt) that are running, and a plate with insect samples made by the students of BIO233 (I was down there today giving them an introduction to barcoding, NorBOL and the BOLD database) – hopefully we’ll get good results on all of it.

-Katrine

Meeting a famous gelatinous neighbour: Bathykorus bouilloni

Every now and then, a hydrozoan species will make the headlines because of the problems it creates for humans in a particular location. Hydrozoan jellyfish may bloom unexpectedly, transforming the water into a gelatinous soup, stinging people and fish in the process, while some hydroids have a tendency togrow  massively in places where they are not wanted. There are others that end up in the news because they produce some unusual protein, or have a peculiar life cycle that could lead to important findings in the fields of medicine or ecology.

Then there is Bathykorus bouilloni, a hydrozoan jelly that has gotten some media attention due to its resemblance to an extremely famous movie character.

This is the original photograph by of a live specimen included in the description of the species, next to a pic of its look-alike. Photo of the jelly: Kevin Raskoff

This is the original photograph of a live specimen included in the description of the species, next to a pic of its look-alike. Photo of the jelly: Kevin Raskoff

This jellyfish was described in 2010 by Dr. Kevin Raskoff, who gave it its appropriate name. Bathykorus is a combination of Bathy (from bathus, meaning depth or deep in Greek) and korus (also from Greek, meaning helmet), and it refers to the deep-sea habitat of the species, as well as to the helmet-like shape of the bell (like that of an intergalactic villain). The word bouilloni in the name of this critter is a tribute to Dr. Jean Bouillon (1926-2009), one of the most prolific authors in Hydrozoan biology in the 20th century.

The species has been known to science only for some years, and indeed very few people may have seen it alive, but this does not necessarily mean that it is an uncommon animal: in fact, it may be extremely abundant in some places and is perhaps one of the most common species living at certain depths in the Central Arctic Ocean.

Caption: the peach-coloured spots in this medusa are most likely the remnants of its last meal. Photo: Aino Hosia

The peach-coloured spots in this medusa are most likely the remnants of its last meal. Photo: Aino Hosia

The wide circular mouth of this animal (a characteristic shared with many other jellyfish in the Order Narcomedusae) is best seen from above. Photo: Aino Hosia

The wide circular mouth of this animal (a characteristic shared with many other jellyfish in the Order Narcomedusae) is best seen from above. Photo: Aino Hosia

We at the HYPNO project are happy to have found this charismatic species off Svalbard, and even more so when it was possible to barcode it through NorBOL!

-Luis


References

Antsulevich, A. E. (2015). Biogeographic and faunistic division of the Eurasian Polar Ocean based on distributions of Hydrozoa (Cnidaria). Journal of the Marine Biological Association of the United Kingdom 95(08): 1533-1539.

Raskoff, K. A. (2010). Bathykorus bouilloni: a new genus and species of deep-sea jellyfish from the Arctic Ocean (Hydrozoa, Narcomedusae, Aeginidae). Zootaxa 2361(1): 57-67.