Mathilde Godefroid has just published a new research paper “Higher daily temperature range at depth is linked with higher thermotolerance in antipatharians from the canary islands”, out in the Journal of Thermal Biology.
Sensitivity to ocean warming is generally expected to be lower in populations from more heterogeneous thermal environments, owing to greater phenotypic plasticity and/or genotype selection. While resilience of benthic populations from thermally fluctuating environments has been investigated at a variety of spatial scales, this has received limited attention across depths and has remained unresolved for Antipatharian corals, key habitat- forming species across a wide bathymetric range in all of the world oceans. In this study, we aimed at addressing the thermal sensitivity of Antipatharian corals across depths characterized by different levels of temperature fluctuations. We used an acute ramping experimental approach to compare the thermal sensitivity of colonies of (1) the branched Antipatharian Antipathella wollastoni (Gray, 1857) from two distinct depths (25 and 40 m) in Gran Canaria (Canary Islands, Spain); and of (2) unbranched mesophotic (80 m) Stichopathes species, from Lanzarote (Canary Islands, Spain; S. gracilis (Gray, 1857)), and Stichopathes sp. clade C from Mo’orea, French Polynesia. Results showed that the daily temperature range in Gran Canaria was larger at mesophotic depths (3.9 ◦C vs. 2.8 ◦C at 40 and 25 m, respectively) and this coincided with lower thermal sensitivity in mesophotic colonies of A. wollastoni. Second, S. gracilis from Lanzarote showed a lower thermal sensitivity than the previously studied Stichopathes sp. clade C from Mo’orea (French Polynesia) inhabiting a less variable habitat. These results are in line with the climate variability hypothesis, which states that populations under more variable thermal conditions have a lower sensitivity to warming than those from more stable environments, as they have adapted/acclimated to these higher levels of temperature fluctuations.
We have just released the TANGO1 expedition report. The report will give you an overview of the activities of the TANGO1 team in the West Antarctic Peninsula, onboard RV Australis.
The TANGO1 expedition ventured to accumulate new data on the responses of marine ecosystems to shifts in ice regimes in the West Antarctic Peninsula (WAP), taking full advantage of a nimble sampling platform, the R/V Australis, a steel hulled, fully rigged motor sailor. TANGO1 took place between February and March 2023, sampling two main locations at different spatial scales. Deploying 14 different types of gear (both traditional and modern), the TANGO1 team gathered over 4000 samples that will be brought back to Belgium for further analysis. The team focused on synchronized, transdiciplinary sampling to understand the linkages between realms (atmosphere, sea-ice, watercolumn, seafloor) and there potential responses to changes in climate-changed linked ice regime at various spatial scales. The use of R/V Australis for coastal studies deemed to be extremely efficient, in terms of environmental impact (ca. 40 times less CO2 emissions than a Polar class icebreaker) and reactivity, allowing the team to adapt the sampling efforts in function of the weather or anchoring conditions. Fully devoted to the expedition, the ship allowed the B121 team to sample in shallow areas, not accessible to icebreaker and too far away from research stations, and which have been under sampled.
The preliminary (meta)results accumulated during TANGO1 confirm the efficiency of using a nimble research platform to study fine-scale processes in the shallow areas of unchartered regions of the West Antarctic Peninsula. TANGO1 provides a first-hand experience to carry an ambitious TANGO2 expedition. Based upon Open Science approaches, the combination of B121/TANGO1 efficiency in sampling paves the way to testing the transposability of the concept to multiply similar efforts in a coordinated fashion. An overview of initial results is provided below: Fine-scale bathymetry An estimated 30 hours were spent to generate sufficient data to generate bathymetric maps All visited sampling sites were charted. The bathymetric exercise allowed reaching a very high sampling efficiency (for example for selecting preferential areas to deploy the SCUBA divers). As a side benefit, the generation charts allowed to identify and flag dangers to navigation which were immediately communicated to relevant hydrographic authorities. Aerial mapping A total of 16 drone flights were carried out during the TANGO1 expedition, generating large quantities of media fit for different purposes. Deployment of drones was found to be useful in terms of scouting when arriving in new work station, documenting their general setup as well as carrying out more sophisticated works including orthomosaic (2D) and photogrammetry (3D). Combined to other georeferenced layer gathered during the TANGO1 expedition (ROV imagery, bathymetry, etc…) the aerial imagery has a promising potential in terms of geospatial analysis at a scale matching the distribution of the sampling efforts. Oceanography In total, 15 CTD profiles were taken in different locations of Dodman Island and Blaiklock Island. Sediment trap were deployed successfully after coordinated recovery of the sample bottle and release by divers and surface recovery. One sediment trap (ST1) has been deployed at Dodman Island while another deployment (ST2) took place in Blaiklock Island. More particles were recovered at Blaiklock Island compared to Dodman Island, suggesting a significantly higher particle fluxes in Blaiklock Island. Sea-ice works We sampled two drifting ice floes: ICE-1 nearby Dodman Island, and ICE-2 at station 3 of Blaiklock island. Even though the ICE-1 floe was drifting, the overall aspect of it, the fact that we observed remaining landfast ice in person or by remote sensing in areas less than 30km away (Dimitrov Cove and Crates Bay respectivally), suggest it was landfast ice recenty detached. Ice floe ICE-2 was found at site 3 of Blaiklock island and was surrounded by floating glacial ice. The floe was thinner and less homogeneous than floe ICE-1 as the floe grew around a piece of glacial ice and was likely a remnant piece of landfast ice. Salinity of the floe was quite low for a first year sea ice, with an uncommon salinity profile. We hypothesize that the low salinity profile observed in Blaiklock, with salinity down to 0 at the surface, was due to rainfall washing down the ice. Soft sediments biodiversity and biogeochemistry The amount of samples and the storage of the samples generated for the sediment biogeochemistry part are available further in the report., In the next year the preliminary data generated during the incubations will be quality checked and the setup will be discussed with colleagues at the Ghent Marine Biology Laboratory. The samples for both the incubation measurements, the sediment environmental data, and the stable isotope analysis will be carried out. The results from the field samples will inform priorities for the upcoming campaigns and will help deciding on the feasibility of such detailed and time- consuming measurements aboard of a nimble vessel that was not originally designed to host these types of technically complex, detailed and time-consuming measurements. Benthic habitat mapping In Dodman Island, 6 different sites were sampled with a total of 20 recorded squares using a Remotely Operated Vehicle (ROV). When a squared-shaped pattern was not possible, the site was sampled by transects. In Blaiklock Island, our second sampling station, 3 contrasting sites were sampled as well as 3 sub-locations in one of the sites to characterize small scale heterogeneity. In total, 12 squares and 2 transects were sampled. Back in the Laboratory, the images will be used to create photomosaics from which we will calculate biodiversity indices ( and ), evenness/dissimilarity indices (Species Richness, Shannon-Wiener, Simpson) and functional diversity (Functional Dispersion, Rao’s Quadriatic Entropy). Then, to compare our results between sites, we will use multivariable correlative approaches (such as a Canonical Correspondence Analysis and NMDS analyses). For characterizing how benthic communities respond to environmental heterogeneities, we will perform Spatial Point Process Analyses (SPPA). To build predictive models, and investigate the drivers of ecosystem responses to their changing environment, we will use Bayesian Network Inference (BNI) analysis. Macro- and megabenthos diversity All sample collected in the different events of Rauschert Dredge and the Amphipod Trap have been partially sorted on board of Australis during the expedition. Representants of the major taxa present in the catch were isolated and counted whenever time and space were available. As agreed during the preparation of the expedition, all sorted taxa and unsorted subsamples were fixed in ethanol to be processed further thoroughly in the lab by master or PhD thesis students. Top Predators census (TOPP) Species encountered in the Magellanic area, Drake Passage, Dodman Island, Blaiklock Island and along the Antarctic Peninsula are enumerated hereunder with preliminary considerations. Overall, most species expected to be seen were observed during this voyage at the exception of the Antarctic Petrel (Thalassoica antarctica) for which not a single individual was found, which is rather unusual especially in the Bransfield Strait and South Shetland Island. Killer Whale (Orcinus orca s.l.) despite our intensive search remained equally out of sight during this expedition. Sea urchins microbiota A total of 150 urchins was processed onboard during the expedition. Due to their high abundance at all locations, there was no issue with the collection of specimens. Sizes however varied strikingly from one location to another, a variability that will be investigated into more details. Samples preserved dried and in ethanol will be analyzed upon return in Belgium for trophic niche characterization. Sexing (observation of gonad tissues) and genetic (test tissue) analyses will also be performed in Belgium as well as DNA extractions for microbiome characterization. Underwater photography This part of the project was a first approach in documenting the work and illustrating biodiversity during the expedition. Many improvements can be implemented and notably having dedicated dives to illustrate a maximum of the diversity encountered. The creation of a reference library for live specimens coupled with DNA barcoding effort is also considered. Such efforts are important and more and more valuable, especially in studies using metabarcoding/eDNA approaches. Diving A total of 30 logged dives were performed by the team of four divers collecting a total of 828 unique samples consisting of sediment cores, photo and videos and handpicking and transect collection of megafauna specimens and macroalgae. The average dive time was 30 min, the maximum dive time was 51 min. The average depth was 19 m and the maximum depth was 25 m. More details will be provided in the dedicated Scientific Diving Activity Report to be found on the Tango I website.
One member of the BIOMAR Lab (Quentin Jossart, scientific collaborator from Univ. Bourgogne) recently realized a fieldwork in the Falkland Islands to investigate intertidal communities. The project aims at better understanding the diversity of these underexplored communities and at characterizing the biogeographic affinities with other regions of the Southern Ocean… while bringing relevant data for conservation purposes.
The intertidal zone (seashore) is a critical environment at the interface of marine and terrestrial habitats, where inter-linked environmental and anthropogenic stressors occur. This zone is also often seen as a sentinel to preliminary detect the presence of non-native species. In polar regions, especially in the Southern Ocean, biological communities living in the intertidal zone remain largely underexplored both at the large scale (biogeographic patterns) and the local scale (main abiotic and biotic factors structuring these communities).
This Falkland Islands fieldwork occurred in the context of a Marie Skłodowska-Curie Postdoctoral Fellowship “BIORISC” (“Biogeography and Resilience of Intertidal Southern Ocean Communities”) and an international collaboration with Narissa Bax (South Atlantic Environmental Research Institute, SAERI). The Falkland Islands represent an ideal study case, considering its various types of habitats and its geographic situation at the convergence of multiple oceanic currents. The fieldwork mainly consisted in the sampling of marine organisms, combined with in situ abundance measurements. A dozen of samplings took place in contrasted sites from the East Falklands, highlighting an important diversity of invertebrates (e.g., crustaceans, mollusks, sea stars). The specimens will be soon further investigated both morphologically and genetically in order to better shed the light on the composition and structure of these communities. In addition, the results will be shared with the Environment Department of the Falkland Islands Government (FIG) for potential use in local conservation purposes.
This research and fieldwork were featured (short interview) on the local FITV channel :
Three members of the BIOMAR Lab are participating in the ongoing TANGO expedition (taking place from 13 February to 19th March 2023). Lea Katz, Camille Moreau and Bruno Danis are currently in Antarctica, onboard RV Australis to contribute to our understanding of Southern Ocean ecosystem responses to environmental change. The expedition is led by Bruno Danis and Camille Moreau and Lea Katz are part of the scientific diving team, and are working on biodiversity and habitat mapping studies pertaining to the TANGO project, funded by the Belgian Science Policy Office (BELSPO).
The TANGO team sampling an ice floe in the Grandidier Channel (West Antarctic Peninsula). Photo: Camille Moreau
The TANGO team includes:
RV Australis crew: Ben Wallis , Ocean Expeditions (Skipper), Annette Bombosch (First mate), Maria Amenabar (Stewardess)
Scientific Party: Bruno Danis, Université Libre de Bruxelles (Chief Scientist), Henri Robert, Environmental Measurements – Conservation & Consciousness, Camille Moreau, Université Libre de Bruxelles, Lea Katz, Université Libre de Bruxelles, Francesca Pasotti, University of Gent (Lead Diver), Marius Buydens, University of Gent, Bruno Delille, University of Liège, Axelle Brusselman, University of Liège, Martin Dogniez, University of Liège
More information is available from the TANGO website.
You can follow the team’s progress on Facebook, Twitter and Instagram. The map below shows the progress of the expedition on Polarstep.
Three members of the BIOMAR, Lea Katz, Camille Moreau and Bruno Danis are now getting ready for a new expedition to the Southern Ocean, onboard a sailboat, the RV Australis (skipped by Ben Wallis, Ocean Expeditions). The TANGO1 expedition is funded by the Belgian Science Policy Office under the BRAIN-BE umbrella.
, The RV Australis, our research platform during the TANGO1 expedition
Lea Katz will be in charge of the ROV (Remotely Operated Vehicle) flights and is a (BSD-certified) scientific diver, Camille Moreau is also a BSD diver and will be in charge of intertidal and benthic sampling and Bruno Danis is leading the expedition. The team will also include researchers from the University of Gent, and University of Liège.
The Bluerobotics ROV we will be deploying during the expedition
A few days before departure, we are in Ushuaia, Argentina to prepare the vessel for the voyage, which will be a continuation of the Belgica 121 expedition, led by Bruno Danis in 2019. The overall objective of the expedition is to contribute to our understaning of ecosystem responses to rapid environmental change in the West Antarctic Peninsula, while using a research platform with limited environmental impact.
Events as Conferences of Parties (CoP) are as important as they are unknown for most people. Everyone has heard of them but only a few know what it is, how it works and what is clearly discussed EXCEPT of course people that work in the field.
On one hand, I knew how big the opportunity was because of my scientific background and the advice of all the scientists with whom I was talking and working. On the other hand, nor my friends or my family were aware of what it was all about, bringing a lot of skepticism.
At that point I understood the importance of sharing my experience, allowing non-scientific people to understand in what way this event was going to impact their future. Whether we want it or not, those decisions are committing all living beings on this planet: We are linked to every other specie as being a part of the ecosystem that we forget too often about.
Let’s begin by a quick rundown of what the CoP19 was about. Each CoP (Conference of Parties) has a main topic discussed between the Parties (signatory countries). In this case, it was the 19th meeting of Parties regarding the protection of endangered species across the world. This protection has become a real dimension with the CITES international agreement that enables a regulation aspect to species’ worldwide trade throughout its annexes. The scientific framework of the term “endangered species” is given by the IUCN which is collecting data from scientists around the world to define according to many features which specie must be classified as an endangered one and accordingly needs protection.
For two weeks from morning to evening, the main topic of our conversations was the protection of endangered species: what more could I ask for!
As part of my Master’s degree, I had the great opportunity this summer to do a three-months internship in Sri Lanka within an NGO called Blue Resources Trust (https://www.blueresources.org/about).
They focus their work on marine conservation and devote particular efforts towards sharks and rays of South Asia. Within this framework, they are actively implicated in policy matter regarding the subject thus have participated in the sharks’ proposals submitted at this CoP19. Knowing that I had a great interest in marine policy, they proposed that I would join them in attending the CoP19 as one of the NGO’s members, giving me the possibility to be at the forefront of decision making.
No great surprise, as soon as I arrived there, I had a strong impostor syndrome hovering over my head. It was even stronger realizing that very few junior participants were attending (which I was quite disappointed about) and that I was surrounded by people that I someday aspire to become, not to mention the fact that I was totally lost in all this new world bringing a lot of information.
As the days passed, the syndrome went away and my admiration for those same people was growing bigger and bigger. Let me tell you why and that goes by explaining how things work during CoPs.
Every day for two weeks, I attended the so-called “Plenary” sessions during which many proposals are discussed. Those sessions are designed to help Parties make official statements about each proposal and debate before the official vote which also happens in Plenary. From an outsider’s perspective, only politicians and delegates of signatory countries seemed to be involved in the matter. But of course, it is the tiny part of the iceberg that you can actually see.
It might seem obvious for some people, but most of politicians’ statement are entirely written by NGO’s. As a biology student, it felt great to see how much scientists are actually involved in decision-making. Not only are they in the field collecting samples and data, analysing them but also, they are involved in policy processes. They stand by politicians, giving them the data and the scientific context, explaining them why species need protection and how this protection can be implemented.
To give a concrete example, Blue Resources Trust along with several other NGO’s worked over years to come up with the requiem of sharks at Cop19 and managed to make it pass by convincing politicians on the matter. A huge part of their work is represented by the implementation tools that they created to enable stakeholders to regulate shark trade in their countries (https://citessharks.org/resources).
Those implementation tools consist of rapid DNA identification kit, identification guides (based on fins or whole-body carcass) and Non-Detrimental Findings (NDF) software that enables officials to know if the trade of a specie is sustainable in their country. To summarize, they made everything possible. It might not be directly their voice making political statements, representing countries at CoPs and other important gatherings but their work behind the scenes is massive. In this particular case, it led to the protection of over 60 shark species!
I do think this last part is as important as the other ones of being a scientist. At the end, data are relevant only if we do positively change by making use of it and often, to change things you have to step into the policy world. This unavoidably involves a lobbying strategy. That is also something that I learnt there at the CoP19: lobby is not necessarily a bad thing. Scientists trying to convince politicians about environmental/species matter is also a way of lobbying.
Scientists are very often categorized as people working in a lab, working out data and writing specialized articles. As future scientists, it’s important to know that we, students, can have an impact and a voice to change things later. For this to be understood by our young generation, we need to be more involved in this kind of political events. It connects us to the active world by meeting people working elsewhere than in our universities and therefore opens us other doors and opportunities for our career.
But most important thing: the sooner we are involved, the sooner we will be efficient in tackling future challenges.
A PhD is full of surprises and one of the firsts for me was to travel to the other side of the world, to French Polynesia, and more specifically to Tetiaroa, Marlon Brando’s atoll, located 60 km North to Tahiti. There, the reefs on the outer slope can be both with a high (~ 40%) and low (~ 5%) coral cover. This is precisely what was interesting for me since I aim to understand how habitat loss influences invertebrate communities inhabiting reefs and how their associated trophic network is subsequently modified.
We left the CRIOBE station (Moorea) early in the morning, caught the first ferry, disembarked in Papeete and after a choppy 2 hours trip on a small motor boat, we finally saw Tetiaroa looming on the horizon. As we got closer, we caught a first glimpse of the atoll : a bright bluewater surrounded by several motus, sometimes separated with small ‘hoa’ and inhabited mainly by palm trees, coconut trees, and ‘aito’, the iron wood.
The atoll is naturally closed, the only way in and out is a small artificial pass in front of Onetahi, the motu on which we were to spend the next two weeks. Once landed, we were welcomed by Loulou and Antonin from the Tetiaroa Society, the island’s small scientific field station. They showed us our rooms, the lab and brought us on a small tour of the motu.
The next day, Alexandre from the CRIOBE joined our team to support us on the field. The first step was to define my sampling sites. I needed both high and low coral cover as a reflect of the reef’s health; hence we went on a manta tow tour from Oroatera to Reiono, via the west side of the atoll. We selected two sites, ~ 2 km apart from each other but both on the North side of the island, respectively in front of Tiara unu and Oroatera.
Once the sites were defined, the real work started. The daily routine was to wake up at 5 am, get the sampling and diving equipments ready to leave around 6:30 and be on the site thirty minutes later. We used to do one or two dives and then to go back at the Tetiaroa field station around 11 am. The rest of the day was dedicated to the samples treatment in the lab.
Underwater, I retrieved Pocillopora colonies, according to their state : alive, dead and dead with algae. I took a picture of each sampled colony in a 1 m2 quadrat and then wrapped the head in a ziplock to prevent inverts from escaping while it was being chiseled, and eventually secured with a serflex. At last, I did a 20 m2 photogrammetry around the colony to assess its close environment.
Of course, this routine was every once in a while interrupted by unexpected encounters …
Back in the lab, colonies were treated separately. Each one was soaked in a basket of fresh water : the inverts obviously weren’t fond of the change and tried to swim away from the colony, which made them easy to collect. They were then sorted according to their size thanks to several sieves, in four different categories (S, M, L and XL). Pictures of each invert samples were taken, the biomass was measured and a photogrammetry of the coral head as well, to assess its structure.
After 11 days, 42 coral colonies and 218 invert samples, the mission was over and left us very tired but overall very happy. I headed back to Moorea and stored my samples at -80°C, where they now wait to be extracted and sequenced !
For the last field mission of my PhD thesis (Year 4, serious things to come!), I was lucky enough to travel to Gran Canaria to join a great team led by Dr Francisco Otero-Ferrer from the Parque Cientifico y Tecnologico Marino de Taliarte (ECOAQUA lab, Universidad Las Palmas de Gran Canaria, https://ecoaqua.ulpgc.es/). Gran Canaria is one of the seven islands composing the Spanish volcanic archipelago of the Canary Islands. It is located in the Atlantic Ocean and became famous as “the Land of endless spring” for its warm weather all year round. I landed on the island on the 29th of September … perfect time to skip some of our most rainy months here in Belgium (lucky me!)
No joke, we decided to work on this project in October-November as sea surface temperatures around the Island are maximal during these months, which is better for our experiment. Our aim is to assess the effects of increasing temperatures on antipatharians (black corals) from the Canary Islands. For this purpose, I was delighted to be working with Adriana Gouveia from Madeira (Portugal) who is doing her master thesis on the subject. Working in pairs is a real plus, allowing us to take turns in the daily tasks (tank cleaning, coral feeding, daily inspection, etc.) but also to be twice more efficient and gaining time. It was also an opportunity for me to train her in the techniques I’ve learned throughout all my fieldwork. Plus, there is always more in two brains than in one and I have no doubt experimentalists know how helpful this can become when work piles up!
We went diving to collect black coral fragments from different colonies at 25m depth. We quickly found several big colonies of unbranched antipatharians. Fran was cutting the fragments and I was taking care of the ziplocks to make sure that we would not lose track of the origin of each fragment. We had some current which made the conditions to collect more challenging but at the end, I think we were amongst the lucky divers as we latter found out that the waves made life harder for those waiting for us on the surface. The story goes that medicine for seasickness were not enough…
Once back to the lab, we directly prepared the nubbin and placed them in aquaria to left them recover from the stress of collection. Later on, we were able to collect new fragments at 40m (Gran Canaria) and 80m depth (Lanzarote). This was possible owing to the collaboration with the ongoing project B-CHARMED (https://b-charmed.eu/en/), which aims at exploring underwater forests of black corals from Macaronesia, using the island of Lanzarote as a case study. All the fragments were used to evaluate the effects of heat stress on antipatharians, by comparing the response of populations from distinct depths.
Results are currently being analysed… updates in the coming months!
Once more, many thanks for the financial support provided by the FNRS and the RBZS institutes in Belgium, as well as to all participants involved in the project: Fran, Adriana, Philippe. Thanks to the precious technical divers: Fran (ULPGC), Fernando Tuya (ULPGC), Fernando Espino (ULPGC), Lorenzo Bramanti (OOB, France), Lucas Terrana (UMons, Belgium). Special thanks to Martial, Sandra, Francesca, Doreen.
Zoologist Péron and artist Lesueur, both members of the scientific staff of the Baudin expedition to the Southern Lands (September 1800-March 1804), collected during their voyage 36 different species of asteroids. This is what wrote Lamarck in a report made in June 1804. This number was clearly reduced by Lamarck himself who, in his 1816 publication, listed only 15 species from the South Seas in the Paris Museum collection. However, the different asteroids collected during the expedition were drawn by Lesueur (water colours and pencil drawings) who thus realised a real pictorial register. Lesu- eur’s drawings are housed in the Le Havre Museum. Due to their realism and precision, the drawings make it easy to identify the species. Confrontation of Lamarck’s report (1804) and publication (1816) with Lesueur’s drawings (done between 1802 and 1804) gives a new, more precise idea of the impor- tance of the collection of South Seas asteroids brought back to France and allows to reliably count the number of new species that it contained. Also, this makes it possible to complete the often too brief descriptions of some Lamarckian species and to clarify their status. Eleven taxonomic changes are thus proposed here: Asterias calcar var. quinqueangula is synonymized with Parvulastra exigua (Lamarck, 1816), Asterias calcitrapa var. 1 with Bollonaster pectinatus (Sladen, 1883), Asterias calcitrapa var. 2 withAstropecten vappa Müller & Troschel, 1843, Asterias nodosa var. 3 with Protoreaster lincki (Blainville, 1830), Asterias pentagonula with Tosia australis Gray, 1840, Asterias pleyadella with Protoreaster sp., Asterias punctata with Asteropsis carinifera (Lamarck, 1816), Asterias rosacea var. lobis senis with Anse- ropoda sp., Asteriscus setaceus with Paranepanthia grandis (H. L. Clark, 1928), Astrogonium lamarckii Müller & Troschel, 1842 with Goniaster tessellatus (Lamarck, 1816) and Asterias cuspidata is moved to the genus Mediaster Stimpson, 1857 as Mediaster cuspidatus (Lamarck, 1816) n. comb.
A new article by Quentin Jossart et al. has just been published in the Zoological Journal of the Linnean Society. Our paper uses an integrative approach in discriminating species, for taxa characterized by the difficulty to identify species based on morphological characters. In this study, we combine genetics and morphology to assess the diversity of Pterasteridae, a sea star family diversified in deep-sea and polar environments. Because of their derived anatomy and the frequent loss of characters during preservation, Pterasteridae are a suitable case for an integrative study. The molecular identification of 191 specimens (mostly from the Southern Ocean) suggests 26–33 species in three genera (Diplopteraster, Hymenaster and Pteraster), which match the morphological identification in 54–62% of cases. The mismatches are either different molecular units that are morphologically indistinguishable (e.g. Pteraster stellifer units 2 and 4) or, conversely, nominal species that are genetically identical (e.g. Hymenaster coccinatus/ densus/praecoquis). Several species are shared between the Northern and Southern Hemispheres (e.g. Pteraster jordani/affinis). In conclusion, the taxonomic status of some groups is confirmed, but for others we find the need to re-evaluate the taxonomy at both genus and species levels. This work significantly increases the DNA barcode library of the Southern Ocean species and merges taxonomic information into an identification key that could become a baseline for future studies (pterasteridae-so.identificationkey.org).
