Contribution of Morphometrics to the Systematics of the Ordovician GenusNeseuretus(Calymenidae, Trilobita) from the Armorican Massif, France

2013

The genusNeseuretusHicks, 1873 is the most abundant trilobite of the Ordovician siltite succession of the Andouillé and Traveusot Formations in the French Armorican massif. The systematics of some species ofNeseuretusis still unclear. Armorican and Iberian domains formed part of a distinctive paleobiogeographical province in the Ordovician and, while fiveNeseuretusspecies were defined in Iberia that follow each other through time, from the Middle to the Upper Ordovician, only oneNeseuretusspecies,N. tristani, has been identified in the Armorican massif so far. The discovery of new fossil deposits in the Ménez-Belair syncline has led to the identification and re-description of threeNeseuretu…

Reproductive strategy as a piece of the biogeographic puzzle: a case study using Antarctic sea stars (Echinodermata, Asteroidea)

2017

13 pages; International audience; AimTo describe and analyse asteroid biogeographic patterns in the Southern Ocean (SO) and test whether reproductive strategy (brooder versus broadcaster) can explain distribution patterns at the scale of the entire class. We hypothesize that brooding and broadcasting species display different biogeographic patterns.LocationSouthern Ocean, south of 45 °S.MethodsOver 14,000 asteroid occurrences are analysed using bootstrapped spanning network (BSN), non-metrical multidimensional scaling (nMDS) and clustering to uncover the spatial structure of faunal similarities among 25 bioregions.ResultsMain biogeographic patterns are congruent with previous works based on…

Phylogeny and origin of Jurassic irregular echinoids (Echinodermata: Echinoidea).

2006

27 pages; International audience; A phylogenetic analysis of Jurassic irregular echinoids is realized to explore the origin and early evolution of this important subset of echinoids. The phylogeny is based on 39 characters and considers data from apical system architecture, the corona including tuberculation and spines, Aristotle's lantern, and general test shape. Results corroborate the monophyly of Irregularia, and clarify the phylogenetic interrelationships existing between the main groups of irregular echinoids. Specializations of the Aristotle's lantern, spines, tubercles and phyllodes constitute the apomorphies for different taxa, as for the whole of Irregularia. The phylogenetic sign…

Taxonomy 2.0: computer-aided identification tools to assist Antarctic biologists in the field and in the laboratory

2020

Species inventories are essential to the implementation of conservation policies to mitigate biodiversity loss and maintain ecosystem services and their value to the society. This is particularly topical with respect to climate change and direct anthropogenic effects on Antarctic biodiversity, with the identification of the most at-risk taxa and geographical areas becoming a priority. Identification tools are often neglected and considered helpful only for taxonomists. However, the development of new online information technologies and computer-aided identification tools provides an opportunity to promote them to a wider audience, especially considering the emerging generation of scientists…

Understanding processes at the origin of species flocks with a focus on the marine Antarctic fauna

2017

Species flocks (SFs) fascinate evolutionary biologists who wonder whether such striking diversification can be driven by normal evolutionary processes. Multiple definitions of SFs have hindered the study of their origins. Previous studies identified a monophyletic taxon as a SF if it displays high speciosity in an area in which it is endemic (criterion 1), high ecological diversity among species (criterion 2), and if it dominates the habitat in terms of biomass (criterion 3); we used these criteria in our analyses. Our starting hypothesis is that normal evolutionary processes may provide a sufficient explanation for most SFs. We thus clearly separate each criterion and identify which biolog…

Large-scale distribution analysis of Antarctic echinoids using ecological niche modelling.

2012

Understanding the factors that determine the distribution of taxa at various spatial scales is a crucial challenge in the context of global climate change. This holds particularly true for polar marine biota that are composed of both highly adapted and vulnerable faunas. We analysed the distribution of 2 Antarctic echinoid species, Sterechinus antarcticus and S. neumayeri, at the scale of the entire Southern Ocean using 2 niche modelling procedures. The performance of distribution models was tested with regard to the known ecology of the species. The respective contributions of environmental parameters are discussed along with the putative roles played by biotic interactions and biogeograph…

Can we generate robust species distribution models at the scale of the Southern Ocean?

2018

17 pages; International audience; AimSpecies distribution modelling (SDM) represents a valuable alternative to predict species distribution over vast and remote areas of the ocean. We tested whether reliable SDMs can be generated for benthic marine organisms at the scale of the Southern Ocean. We aimed at identifying the main large‐scale factors that determine the distribution of the selected species. The robustness of SDMs was tested with regards to sampling effort, species niche width and biogeography.LocationSouthern Ocean.MethodsThe impact of sampling effort was tested using two sets of data: one set with all presence‐only data available until 2005, and a second set using all data avail…

Recent climate variability around the Kerguelen Islands (Southern Ocean) seen through weather regimes

2021

AbstractDaily weather regimes are defined around the Kerguelen Islands (Southern Ocean) based on daily 500 hPa geopotential height anomalies derived from the ERA5 ensemble reanalysis over the period 1979-2018. Ten regimes are retained as significant. Their occurrences are highly consistent across reanalysis ensemble members. Regimes show weak seasonality and non-significant long-term trends in their occurrences. Their sequences are usually short (1-3 days), with extreme persistence values above 10 days. Seasonal regime frequency is mostly driven by the phase of the Southern Annular Mode over Antarctica, mid-latitude dynamics over the Southern Ocean like the Pacific South American mode, and …

Fossil echinoid (Echinoidea, Echinodermata) diversity of the Early Cretaceous (Hauterivian) in the Paris Basin (France).

2013

11 pages; International audience; This dataset inventories occurrence records of fossil echinoid specimens collected in the Calcaires à Spatangues Formation (CSF) that crops out in the southeast of the Paris Basin (France), and is dated from the Acanthodiscus radiatus chronozone (ca. 132 Ma, early Hauterivian, Early Cretaceous). Fossil richness and abundance of the CSF has attracted the attention of palaeontologists since the middle of the nineteenth century. This dataset compiles occurrence data (referenced by locality names and geographic coordinates with decimal numbers) of fossil echinoids both collated from the literature published over a century and a half, and completed by data from …

Extinction and recolonization of maritime Antarctica in the limpet Nacella concinna (Strebel, 1908) during the last glacial cycle: toward a model of …

2013

Quaternary glaciations in Antarctica drastically modified geographical ranges and population sizes of marine benthic invertebrates and thus affected the amount and distribution of intraspecific genetic variation. Here, we present new genetic information in the Antarctic limpet Nacella concinna, a dominant Antarctic benthic species along shallow ice-free rocky ecosystems. We examined the patterns of genetic diversity and structure in this broadcast spawner along maritime Antarctica and from the peri-Antarctic island of South Georgia. Genetic analyses showed that N. concinna represents a single panmictic unit in maritime Antarctic. Low levels of genetic diversity characterized this population…

Evolution to the extreme: origins of the highly modified apical system in pourtalesiid echinoids

2004

The apical system of the genus Pourtalesia displays a plate architecture that falls so far outside that typical of other echinoids that plate homologies remain problematic. A new approach using the Extraxial–Axial Theory (EAT) that develops homologies for the Echinodermata is proposed. The exploration of apical plate patterns throughout ontogenetic sequences shows that the typical holasteroid pattern found in the youngest specimens undergoes a series of disturbances that result in a multiple disjunction accompanied by isolation or disappearance of certain genital plates. We propose a new interpretation of the apical architecture of the genus that agrees with: (1) the plate addition processe…

Éco-régionalisation et conservation des communautés benthiques de la zone économique exclusive française des îles Kerguelen

2017

The deep-sea benthic ecosystems of the French Kerguelen exclusive economic zone remain poorly understood. To address benthic conservation issues, the authors recently contributed expert knowledge to guide the recent extension of the Marine Reserve of the ‘Terres australes françaises’. In this new study, we propose a benthic ecoregionalisation of the northern Kerguelen Plateau based on a measurable and repeatable methodology that relies on the generalised dissimilarity modelling technique. Data of macro-epibenthic invertebrate species from the POKER 2 (2010) fish stock assessment survey have been used to compute the models. Our results allow us (i) to characterise and map benthic landscape u…

Le genre Nucleolites (Echinoidea, Cassiduloidea) du Bajocien à l'Oxfordien dans le Bassin de Paris : apport des données architecturales à la systémat…

2005

International audience; La classification des espèces du genre Nucleolites de l'intervalle Bajocien­Oxfordien du bassin de Paris est révisée. Une vision classique, jusqu'alors utilisée par les auteurs et fondée principalement sur la morphologie générale du test, est tout d'abord présentée. Elle est ensuite modifiée à partir de nouvelles données architecturales se référant au modèle extraxial­axial concernant la structure de l'appareil apical ainsi que la présence de plaques supplémentaires et de plaques caténales. Ces données architecturales sont considérées comme prioritaire vis-à-vis de la morphologie générale du test. Cette approche conduit à une nouvelle vision de la classification des …

Patterns of genetic diversity and structure in Antarctic and sub-Antarctic Nacella (Patellogastropoda: Nacellidae) species.

2016

10 pages; International audience; The biogeography of the Southern Ocean reflects complex interactions between major macro-evolutionary forces and biotic elements. Major gateway openings, the establishment of the Antarctic Circumpolar Current and climate cooling are deeply connected to the composition, abundance and distribution of the Southern Ocean marine benthic fauna. Glacial episodes of the Quaternary heavily impacted the distribution of the genetic variation of the Southern Ocean biota. The genus Nacella includes 12 nominal species in different provinces of the Southern Ocean. In this study, we compared patterns of mitochondrial DNA diversity in three Nacella species from Antarctic Pe…

Ectosymbiosis associated with cidaroids (Echinodermata: Echinoidea) promotes benthic colonization of the seafloor in the Larsen Embayments, Western A…

2011

7 pages; International audience; Ice-shelf collapses in the Larsen A and B embayments along the Weddell side of the Antarctic Peninsula resulted in new open-water areas that are likely reorganizing benthic communities. It is a natural laboratory to assess colonization of the sea bottom under new conditions. We tested the hypothesis that the epibionts associated to cidaroid echinoids could promote or enhance the colonization of hard surfaces. In fact, being vagile, cidaroids might improve dispersal capabilities of the sessile animals that are attached to their spines, e.g., promoting the colonization of areas where the fauna has been eradicated by iceberg scouring. If this hypothesis is corr…

The morphology, ontogeny, and inferred behaviour of the deep-sea echinoid Calymne relicta (Holasteroida).

2009

The deep-sea holasteroid Calymne relicta was first described from a few fragments discovered by the HMS ‘Challenger’ in the Bermuda abyssal plain more than a century ago. In addition to re-examining the type material, we describe herein new specimens from unpublished material collected between 3720 and 4860 m during three scientific expeditions that took place on both sides of the North Atlantic between 1966 and 1991. The new material includes juvenile and adult specimens in sufficiently good preservational state to allow a full redescription, including all types of appendages, some of which have never been described. These new observations confirm the atypical characteristics of C. relicta…

The phylogenetic position and taxonomic status of Sterechinus bernasconiae Larrain, 1975 (Echinodermata, Echinoidea), an enigmatic Chilean sea urchin

2015

15 pages; International audience; Sterechinus is a very common echinoid genus in benthic communities of the Southern Ocean. It is widely distributed across the Antarctic and South Atlantic Oceans and has been the most frequently collected and intensively studied Antarctic echinoid. Despite the abundant literature devoted to Sterechinus, few studies have questioned the systematics of the genus. Sterechinus bernasconiae is the only species of Sterechinus reported from the Pacific Ocean and is only known from the few specimens of the original material. Based on new material collected during the oceanographic cruise INSPIRE on board the R/V Melville, the taxonomy and phylogenetic position of th…

Environmental and ontogenetic constraints on developmental stability in the spatangoid sea urchin Echinocardium (Echinoidea)

2006

Biogeosciences, UMR-CNRS 5561, Universite de Bourgogne, 6 bd Gabriel, 21000 Dijon, FranceReceived 25 June 2004; accepted for publication 25 July 2005Spatangoid irregular sea urchins are detritivorous benthic organisms particularly prone to variations of environ-ment, and their mode of growth and plate morphology make them an appropriate model to assess the effects of envi-ronmental variations. Two populations of Echinocardium flavescens were sampled in two sites of the Norwegiancoast characterized by contrasted environmental conditions. Different morphological descriptors (plate areas, inter-landmarks distances, overall size, and shape of the posterior ambulacra) were used to appraise interi…

Empirical and theoretical study of atelostomate (Echinoidea, Echinodermata) plate architecture: using graph analysis to reveal structural constraints.

2015

AbstractDescribing patterns of connectivity among organs is essential for identifying anatomical homologies among taxa. It is also critical for revealing morphogenetic processes and the associated constraints that control the morphological diversification of clades. This is particularly relevant for studies of organisms with skeletons made of discrete elements such as arthropods, vertebrates, and echinoderms. Nonetheless, relatively few studies devoted to morphological disparity have considered connectivity patterns as a level of morphological organization or developed comparative frameworks with proper tools. Here, we analyze connectivity patterns among apical plates in Atelostomata, the m…

A revision of the rare genusCyclolampas(Echinoidea) using morphometrics with description of a new species from the upper Callovian of Burgundy (Franc…

2013

The discovery of a new species,Cyclolampas altusnew species in the upper Callovian of Burgundy (France) leads to the systematic revision of the rare echinoid genusCyclolampasPomel, 1883. Two morphometric approaches are used jointly to describe and quantify variations in test shape: the analysis of linear measurements and the Elliptic Fourier shape analysis. Both analyses yield congruent results that highlight the amplitude of within-species variations and quantify the part due to allometry. Along with the description ofC. altus, the systematic position of species formerly assigned to the generaPygorhytisPomel, 1883 andCyclolampasis amended. Previously attributed to the genusPygorhytis,Cyclo…

Antarctic, Sub-Antarctic and cold temperate echinoid database

2012

6 pages; International audience; This database includes spatial data of Antarctic, Sub-Antarctic and cold temperate echinoid distribution (Echinodermata: Echinoidea) collected during many oceanographic campaigns led in the Southern Hemisphere from 1872 to 2010. The dataset lists occurrence data of echinoid distribution south of 35°S latitude, together with information on taxonomy (from species to genus level), sampling sources (cruise ID, sampling dates, ship names) and sampling sites (geographic coordinates and depth). Echinoid occurrence data were compiled from the Antarctic Echinoid Database (David et al. 2005a), which integrates records from oceanographic cruises led in the Southern Oce…

Contrasting biogeographical patterns in Margarella (Gastropoda: Calliostomatidae: Margarellinae) across the Antarctic Polar Front

2021

International audience; Members of the trochoidean genus Margarella (Calliostomatidae) are broadly distributed across Antarctic and sub-Antarctic ecosystems. Here we used novel mitochondrial and nuclear gene sequences to clarify species boundaries and phylogenetic relationships among seven nominal species distributed on either side of the Antarctic Polar Front (APF). Molecular reconstructions and species-delimitation analyses recognized only four species: M. antarctica (the Antarctic Peninsula), M. achilles (endemic to South Georgia), M. steineni (South Georgia and Crozet Island) and the morphologically variable M. violacea (=M. expansa, M. porcellana and M. pruinosa), with populations in s…

Description of two new fossil echinoids (Echinodermata: Echinoidea) from the Early Hauterivian (Early Cretaceous) of the Paris Basin (France)

2012

International audience; Deux nouveaux genres et espèces d'échinides, Salvaster roberti gen. et sp. nov. et Pygolampas edita gen. et sp. nov. provenant de la Formation des Calcaires à Spatangues (CSF) sont décrits. La CSF correspond à des sédiments calcaréo-argileux déposés dans le sud-est du bassin de Paris (France) à l'Hauterivien inférieur (Crétacé inférieur). Ces dépôts sont datés de la chronozone à Acanthodiscus radiatus, un intervalle de temps qui a correspondu à un haut niveau marin général en Europe de l'Ouest. La CSF a pourtant livré une riche faune fossile d'environnement marin peu profond, principalement représentée par des invertébrés benthiques. Parmi ceux-ci, 54 espèces d'échin…

Palaeobiogeography of Austral echinoid faunas: a first quantitative approach

2013

Few studies have been devoted to the palaeobiogeography of Antarctic echinoids, all of them analysing and discussing distribution patterns in a qualitative way. The present work aims at exploring the evolution of palaeobiogeographic relationships of Austral echinoid faunas through four time intervals, from the Maastrichtian to the present day, using a quantitative approach: the Bootstrapped Spanning Network procedure. Analyses were successfully performed and improve our knowledge of biogeographic relationships between the different Austral regions. Biogeographic maps were produced that can be easily and intuitively discussed. Our results mostly agree with palaeobiogeographic studies perform…

Cryptic speciation in Southern Ocean Aequiyoldia eightsii (Jay, 1839): Mio-Pliocene trans-Drake Passage separation and diversification

2019

Abstract The species of the genus Aequiyoldia Soot-Ryen, 1951, previously known as Yoldia, are common, soft-substratum, sareptid bivalves. In the Southern Ocean, Aequiyoldia eightsii (Jay, 1839) was originally described from the Antarctic Peninsula and has also been reported in southern South America. The species A. woodwardi (Hanley, 1960) was reported for the Falkland/Malvinas Islands and Tierra del Fuego, but this taxon has been recently synonymised within the broadly distributed A. eightsii. Aequiyoldia has received little attention across its distribution in the Southern Ocean, and although its taxonomy and systematics remain uncertain, all the species have been grouped under a single …

The macro- and megabenthic fauna on the continental shelf of the eastern Amundsen Sea, Antarctica.

2013

11 pages; International audience; In 2008 the BIOPEARL II expedition on board of RRS James Clark Ross sailed to the eastern Amundsen Sea Embayment and Pine Island Bay, one of the least studied Antarctic continental shelf regions due to its remoteness and ice cover. A total of 37 Agassiz trawls were deployed at depth transects along the continental and trough slopes. A total of 5469 specimens, belonging to 32 higher taxonomic groups and more than 270 species, were collected. Species richness per station varied from 1 to 55. The benthic assemblages were dominated by echinoderms and clearly different to those in the Ross, Scotia and Weddell seas. Here we present the macro- and megafaunal assem…

Comparative biogeography of echinoids, bivalves and gastropods from the Southern Ocean.

2013

ABSTRACTAim Biogeographical patterns within three classes, the Echinoidea, Bivalvia andGastropoda, were investigated in Antarctic, sub-Antarctic and cold-temperateareas based on species occurrence data. Faunal similarities among regions wereanalysed to: (1) test the robustness of the biogeographical patterns previouslyidentified in bivalves and gastropods; (2) compare them with the biogeographi-cal patterns identified for echinoids; and (3) evaluate the reliability of the bio-geographical provinces previously proposed, depending on the taxa andtaxonomic levels analysed.Location The Southern Ocean, sub-Antarctic islands and cold-temperate areassouth of 45° S latitude at depths of < 1000 m.Meth…

East Weddell Sea echinoids from the JR275 expedition

2015

1 pages; International audience; Information regarding the echinoids in this dataset is based on the Agassiz Trawl (AGT) and epibenthic sledge (EBS) samples collected during the British Antarctic Survey cruise JR275 on the RRS James Clark Ross in the austral summer 2012. A total of 56 (1 at the South Orkneys and 55 in the Eastern Weddell Sea) Agassiz Trawl and 18 (2 at the South Orkneys and 16 in the Eastern Weddell Sea) epibenthic sledge deployments were performed at depths ranging from ~280 to ~2060 m. This presents a unique collection for the Antarctic benthic biodiversity assessment of an important group of benthic invertebrates. In total 487 specimens belonging to six families, 15 gene…

Biodiversity change after climate-induced ice-shelf collapse in the Antarctic

2011

Julian Gutt ... et al. -- 10 pages, 5 figures, 1 table, supplementary data https://doi.org/10.1016/j.dsr2.2010.05.024

Antarctic and Sub-Antarctic Asteroidea database

2018

The present dataset is a compilation of georeferenced occurrences of asteroids (Echinodermata: Asteroidea) in the Southern Ocean. Occurrence data south of 45°S latitude were mined from various sources together with information regarding the taxonomy, the sampling source and sampling sites when available. Records from 1872 to 2016 were thoroughly checked to ensure the quality of a dataset that reaches a total of 13,840 occurrences from 4,580 unique sampling events. Information regarding the reproductive strategy (brooders vs. broadcasters) of 63 species is also made available. This dataset represents the most exhaustive occurrence database on Antarctic and Sub-Antarctic asteroids.

Changement climatique et suivi de la biodiversité marine côtière aux Iles Kerguelen

2018

Nearshore marine habitats of the French sub-Antarctic islands concentrate a rich and unique biodiversity that is currently facing climate change and its still not well-understood and multifaceted effects. Understanding the impact of these changes and predicting the potential response of ecosystems requires advanced knowledge of marine life and the achievement of uninterrupted and long-term observing programs. The Proteker program, no. 1044 of the French Polar Institute Paul-Émile Victor, has been developped in partnership with the National Nature Reserve of French Southern Territories in order to establish an observatory of coastal marine biodiversity in the Kerguelen Islands and evaluate t…

Les échinodermes.

2021

Biodiversité de l’océan Austral - Laboratoire naturel pour l’évolution.

2015

158 pages; National audience; La position quasi polaire de l’océan Austral, ses dimensions et son isolement en font un monde à part, défini par la violence des tempêtes, des températures très basses et d'immenses zones englacées.De tels paramètres climatiques et océanographiques ont façonné la biodiversité de cet océan. Endémisme, métabolisme ralenti, longévité, gigantisme, absence de phases larvaires… Autant d’éléments qui caractérisent un extraordinaire laboratoire naturel pour l’exploration des processus adaptatifs, évolutifs et écologiques à l'oeuvre dans des conditions extrêmes.Cet ouvrage présente les investigations scientifiques les plus récentes de l’océan Austral, son histoire clim…

Kerguelen, un observatoire scientifique dans le Grand Sud.

2018

8 pages; National audience

L'étonnante collection Reboul-Baron : un cabinet de curiosités pour l'étude des anomalies et des monstruosités chez les oursins fossiles.

2018

Following the Antarctic Circumpolar Current: patterns and processes in the biogeography of the limpet Nacella (Mollusca: Patellogastropoda) across th…

2017

14 pages; International audience; AimWe use an integrative biogeographical approach to further understand the evolution of an important Southern Ocean marine benthic element, the limpet genus Nacella (Mollusca: Patellogastropoda).LocationSouthern Ocean.MethodsWe used multi-locus time-calibrated phylogeny of Nacella at the scale of the whole Southern Ocean to elucidate the underlying processes involved in the origin and diversification of the genus.ResultsDivergence-time estimates suggest that soon after its origin during the mid-Miocene (c. 12.5 Ma), Nacella separated into two main lineages currently distributed in (1) South America and (2) Antarctica and the sub-Antarctic islands. We ident…

Kerguelen, un archipel sous haute surveillance

2016

Avec ses c&ocirc;tes d&eacute;coup&eacute;es et sans cesse battues par les vents, les Kerguelen sont rest&eacute;es longtemps inaccessibles aux biologistes marins. Si sa situation g&eacute;ographique et son isolement exceptionnels rendent cet archipel particuli&egrave;rement vuln&eacute;rable aux changements climatiques, ils en font aussi un laboratoire id&eacute;al pour en &eacute;tudier les effets&hellip;

Environmental and ontogenetic constraints on developmental stability in the spatangoid sea urchin Echinocardium (Echinoidea).

2006

13 pages; International audience; Spatangoid irregular sea urchins are detritivorous benthic organisms particularly prone to variations of environment, and their mode of growth and plate morphology make them an appropriate model to assess the effects of environmental variations. Two populations of Echinocardium flavescens were sampled in two sites of the Norwegian coast characterized by contrasted environmental conditions. Different morphological descriptors (plate areas, interlandmarks distances, overall size, and shape of the posterior ambulacra) were used to appraise interindividual variations, and fluctuating asymmetry. The comparisons were carried out using classical fluctuating asymme…

Absence inattendue d'espèces endémiques insulaires: Dissémination sur de longues distances chez des espèces de Siphonaria sub-antarctique de haute la…

2018

International audience; Aim: We assess biogeographical patterns, population structure and the range of species in the pulmonate genus Siphonaria across the sub‐Antarctic. We hypothesized that locally endemic cryptic species will be found across the distribution of these direct‐developing limpets in the sub‐Antarctic.Location: The sub‐Antarctic coasts of the Southern Ocean including South America, the Falkland/Malvinas, South Georgia, Kerguelen and Macquarie Islands.Methods: Multi‐locus phylogenetic reconstructions, mtDNA time‐calibrated divergence time estimations and population‐based analyses of Siphonaria populations were used at the scale of the Southern Ocean.Results: We resolve two wid…

Echinoids.

2014

La biodiversité au Sinémurien.

2021

3 pages; National audience

Les faunes d'échinodermes.

2013

4 pages; National audience

A revision of the rare genus Cyclolampas (Echinoidea) using morphometrics with description of a new species from the upper Callovian of Burgundy (Fra…

2013

18 pages; International audience; The discovery of a new species, Cyclolampas altus new species in the upper Callovian of Burgundy (France) leads to the systematic revision of the rare echinoid genus Cyclolampas Pomel, 1883. Two morphometric approaches are used jointly to describe and quantify variations in test shape: the analysis of linear measurements and the Elliptic Fourier shape analysis. Both analyses yield congruent results that highlight the amplitude of within-species variations and quantify the part due to allometry. Along with the description of C. altus, the systematic position of species formerly assigned to the genera Pygorhytis Pomel, 1883 and Cyclolampas is amended. Previou…

Genetic structure and demographic inference of the regular sea urchin Sterechinus neumayeri (Meissner, 1900) in the Southern Ocean: the role of the l…

2018

22 pages; International audience; One of the most relevant characteristics of the extant Southern Ocean fauna is its resiliency to survive glacial processes of the Quaternary. These climatic events produced catastrophic habitat reductions and forced some marine benthic species to move, adapt or go extinct. The marine benthic species inhabiting the Antarctic upper continental shelf faced the Quaternary glaciations with different strategies that drastically modified population sizes and thus affected the amount and distribution of intraspecific genetic variation. Here we present new genetic information for the most conspicuous regular sea urchin of the Antarctic continental shelf, Sterechinus…

Echinodermata.

2021

Data from: Extinction and recolonization of maritime Antarctica in the limpet Nacella concinna (Strebel, 1908) during the last glacial cycle: toward …

2013

Quaternary glaciations in Antarctica drastically modified geographical ranges and population sizes of marine benthic invertebrates and thus affected the amount and distribution of intraspecific genetic variation. Here, we present new genetic information in the Antarctic limpet Nacella concinna, a dominant Antarctic benthic species along shallow ice-free rocky ecosystems. We examined the patterns of genetic diversity and structure in this broadcast spawner along maritime Antarctica and from the peri-Antarctic island of South Georgia. Genetic analyses showed that N. concinna represents a single panmictic unit in maritime Antarctic. Low levels of genetic diversity characterized this population…

Data from: Empirical and theoretical study of Atelostomate (Echinoidea, Echinodermata) plate architecture: using graph analysis to reveal structural …

2015

Describing patterns of connectivity among organs is essential for identifying anatomical homologies among taxa. It is also critical for revealing morphogenetic processes and the associated constraints that control the morphological diversification of clades. This is particularly relevant for studies of organisms with skeletons made of discrete elements such as arthropods, vertebrates, and echinoderms. Nonetheless, relatively few studies devoted to morphological disparity have considered connectivity patterns as a level of morphological organization or developed comparative frameworks with proper tools. Here, we analyze connectivity patterns among apical plates in Atelostomata, the most dive…

Physical oceanography, sea-bed photographs and videos of benthos from the Weddell Sea taken with remote operated vehicle CHEROKEE during POLARSTERN c…

2010

The marine ecosystem on the eastern shelf of the Antarctic Peninsula was surveyed 5 and 12 years after the climate-induced collapse of the Larsen A and B ice shelves. An impoverished benthic fauna was discovered, that included deep-sea species presumed to be remnants from ice-covered conditions. The current structure of various ecosystem components appears to result from extremely different response rates to the change from an oligotrophic sub-ice-shelf ecosystem to a productive shelf ecosystem. Meiobenthic communities remained impoverished only inside the embayments. On local scales, macro- and mega-epibenthic diversity was generally low, with pioneer species and typical Antarctic megabent…