Éditeur(s) : HAL CCSD Elsevier
Résumé : International audience
Despite the importance of invertebrate resources for Pacific coral reef islands, few studies have specifically addressed the effects of harvesting on invertebrate assemblages including targeted and non-targeted species. The impacts of recreational harvesting on reef and seagrass invertebrate assemblages in New Caledonia (South Pacific) are investigated by comparing communities in non-MPA and MPA areas. Sampling was done using a standard core method on seagrasses and by visual survey along belt transects on reefs. A total of 371 species were recorded, 174 on seagrasses and 254 on reefs, with 57 common species. Reef and seagrass invertebrate communities were very different in MPA and non-MPA areas. On both habitats, MPAs were identified as undisturbed areas while non-MPAs were defined as moderately disturbed with a predominance of small-sized and opportunistic species. Fishing not only affects target species but also non-target species through secondary effects. These results highlight the necessity of a community based approach for the conservation of resources in tropical poorly known environments.
ISSN: 0165-7836

hal-01311486
http://hal.univ-reunion.fr/hal-01311486
http://hal.univ-reunion.fr/hal-01311486/document
http://hal.univ-reunion.fr/hal-01311486/file/Harvesting%20effects%20on%20tropical%20invertebrate%20assemblages%20in%20New_hal.pdf
DOI : 10.1016/j.fishres.2015.02.001

Éditeur(s) : HAL CCSD Public Library of Science
Résumé : International audience
The scleractinian coral Pocillopora damicornis type β is known to present a mixed reproduction mode: through sexual reproduction, new genotypes are created, while asexual reproduction insures their propagation. In order to investigate the relative proportion of each reproduction mode in P. damicornis type β populations from Reunion Island, Indian Ocean, clonal propagation along the west coast was assessed through four sampling sites with increasing geographical distance between sites. Coral colonies were sampled either exhaustively, randomly or haphazardly within each site, and genotypic diversity was assessed using 13 microsatellite loci over a total of 510 P. damicornis type β determined a posteriori from their mtDNA haplotype (a 840 bp sequenced fragment of the Open Reading Frame). Overall, 47% of all the sampled colonies presented the same multi-locus genotype (MLG), a superclone, suggesting that asexual propagation is extremely important in Reunion Island. Within each site, numerous MLGs were shared by several colonies, suggesting local clonal propagation through fragmentation. Moreover, some of these MLGs were found to be shared among several sites located 40 km apart. While asexual reproduction by fragmentation seems unlikely over long distances, our results suggest a production of parthenogenetic larvae. Despite shared MLGs, two differentiated clusters were enclosed among populations of the west coast of Reunion Island, revealing the necessity to set up appropriate managing strategies at a local scale.
ISSN: 1932-6203

hal-01450078
http://hal.univ-reunion.fr/hal-01450078
DOI : 10.1371/journal.pone.0169692

Éditeur(s) : HAL CCSD Springer
Résumé : International audience
With the development of genetics methods, it becomes possible to study the population structure and some aspects of the reproductive behaviour of endangered sharks. Here we describe the isolation of 20 polymorphic microsatellite markers in the bull shark Carcharhinus leucas (Carcharhinidae) and their characteristics. Two to 10 alleles per locus were detected. Observed and expected heterozygosities ranged from 0.00 to 0.78 and from 0.05 to0.80, respectively. Four markers showed deviations from Hardy–Weinberg equilibrium; among them, three showed presence of null alleles. No linkage disequilibrium was detected among any of the loci. Moreover, four, 11 and 19 of these 20 markers successfully cross-amplified in the tiger shark Galeocerdo cuvier, the sandbar shark Carcharhinus plumbeus and the dusky shark Carcharhinus obscurus, respectively.
ISSN: 1877-7252

hal-01253773
https://hal.archives-ouvertes.fr/hal-01253773
https://hal.archives-ouvertes.fr/hal-01253773/document
https://hal.archives-ouvertes.fr/hal-01253773/file/Pirog%20et%20al.%20-%202015%20-%20Isolation%20and%20characterization%20of%2020%20microsatellit_hal.pdf
DOI : 10.1007/s12686-014-0308-3

Éditeur(s) : HAL CCSD National Shellfisheries Association
Résumé : International audience
Monitoring gonad maturation for protandrous and functional hermaphrodite species such as the giant clam Tridacna maxima is difficult due to the juxtaposition and relative proportion of male and female tissues in the gonad [gonadal sex ratio (GSR)]. Here, the relevance of the widely used gonadosomatic index (GSI) as proxy of giant clam gonad maturation is tested with a large dataset (n ¼ 265). Gonadosomatic index is compared with other indices, namely the proportion of the male part harboring spermatozoids, the proportion of empty oocyte follicles, the mean oocyte diameter, and the oocyte elongation. At gonad scale, high index variability highlighted partial spawning. At individual scale, male and female maturation proxies were contrasted, showing either asynchronous emissions of male and female gametes or contrasted spermatogenesis and oogenesis duration. The GSI was mostly driven by the number and diameter of oocytes and therefore it is recommended here as primary proxy for female maturity. Except for the oocyte elongation, all indices were affected by the GSR, which ruled out drawing conclusions at population scale. These results highlight the need for maturation stage proxies that are optimized for functional hermaphrodite species.
ISSN: 0730-8000

hal-01613648
https://hal.archives-ouvertes.fr/hal-01613648
https://hal.archives-ouvertes.fr/hal-01613648/document
https://hal.archives-ouvertes.fr/hal-01613648/file/Gaertner-Mazouni-2016-eio.pdf
DOI : 10.2983/035.035.0107

Éditeur(s) : HAL CCSD
Résumé : International audience
Many countries are legally obliged to embrace ecosystem-based approaches to fisheries management. Reductions in bycatch and physical habitat damage are now commonplace, but mitigating more sophisticated impacts associated with the ecological functions of target fisheries species are in their infancy. Here we model the impacts of a parrotfish fishery on the future state and resilience of Caribbean coral reefs, enabling us to view the tradeoff between harvest and ecosystem health. We find that the implementation of a simple and enforceable size restriction of >30 cm provides a win:win outcome in the short term, delivering both ecological and fisheries benefits and leading to increased yield and greater coral recovery rate for a given harvest rate. However, maintaining resilient coral reefs even until 2030 requires the addition of harvest limitations (<10% of virgin fishable biomass) to cope with a changing climate and induced coral disturbances, even in reefs that are relatively healthy today. Managing parrotfish is not a panacea for protecting coral reefs but can play a role in sustaining the health of reefs and high-quality habitat for reef fisheries.
http://hal.univ-reunion.fr/hal-01369752

hal-01369752
http://hal.univ-reunion.fr/hal-01369752
DOI : 10.1073/pnas.1601529113

Éditeur(s) : HAL CCSD Oxford University Press (OUP)
Résumé : International audience
The newly-desribed Centropyge cocosensis has long been considered a variant of the lemonpeel pygmy angelfish C. flavissima because of their overall similarity in color patterns. DiBattista and co-authors [J. Hered. 107 (2016) 647–653] recently contested the validity of C. cocosensis, based on arguments that are challenged here.
ISSN: 0022-1503

ird-01525431
http://hal.ird.fr/ird-01525431
http://hal.ird.fr/ird-01525431/document
http://hal.ird.fr/ird-01525431/file/Letter%20to%20Editor_JHered%20p%20haL.pdf
DOI : 10.1093/jhered/esx008

Éditeur(s) : HAL CCSD MDPI
Résumé : International audience
Marine ecosystems cover about 70% of the planet surface and are still an underexploited source of useful metabolites. Among microbes, filamentous fungi are captivating organisms used for the production of many chemical classes of secondary metabolites bound to be used in various fields of industrial application. The present study was focused on the collection, isolation, screening and genotyping of pigmented filamentous fungi isolated from tropical marine environments around La Réunion Island, Indian Ocean. About 150 micromycetes were revived and isolated from 14 marine samples (sediments, living corals, coral rubble, sea water and hard substrates) collected in four different locations. Forty-two colored fungal isolates belonging to 16 families, 25 genera and 31 species were further studied depending on their ability to produce pigments and thus subjected to molecular identification. From gene sequence analysis, the most frequently identified colored fungi belong to the widespread Penicillium, Talaromyces and Aspergillus genera in the family Trichocomaceae (11 species), then followed by the family Hypocreaceae (three species). This study demonstrates that marine biotopes in La Réunion Island, Indian Ocean, from coral reefs to underwater slopes of this volcanic island, shelter numerous species of micromycetes, from common or uncommon genera. This unstudied biodiversity comes along with the ability for some fungal marine inhabitants, to produce a range of pigments and hues.
ISSN: 2309-608X

hal-01657071
http://hal.univ-reunion.fr/hal-01657071
http://hal.univ-reunion.fr/hal-01657071/document
http://hal.univ-reunion.fr/hal-01657071/file/14-%20Fouillaud%20et%20al.%2C%20J.%20of%20Fungi%202017.pdf
DOI : 10.3390/jof3030036

Éditeur(s) : HAL CCSD Elsevier
Résumé : International audience
We isolated and characterized 26 microsatellite loci for Macrorhynchia phoenicea (Busk, 1852), a rather common tropical hydrozoan from the Indo-Pacific. The number of alleles per locus ranged from 4 to 24. The observed heterozygosity ranged from 0.000 to 0.970 and the expected heterozygosity from 0.029 to 0.833. Ten loci were at HardyeWeinberg equilibrium. No pair of loci presented linkage disequilibrium. Transferability of up to 18 loci was positive across four other Aglaopheniidae species from different genera. These loci will be used in studying reef population connectivity for these particular species at the scale of the Indo-Pacific, a promising but little explored research field.
ISSN: 0305-1978

hal-01253779
https://hal.archives-ouvertes.fr/hal-01253779
https://hal.archives-ouvertes.fr/hal-01253779/document
https://hal.archives-ouvertes.fr/hal-01253779/file/Biochemical%20Systematics%20and%20Ecology%202015%20Postaire_hal.pdf
DOI : 10.1016/j.bse.2015.08.011

Éditeur(s) : HAL CCSD Wiley
Résumé : International audience
Bruggemann, J.H. (2016). Phylogenetic relationships within Aglaopheniidae (Cnidaria, Hydrozoa) reveal unexpected generic diversity. — Zoologica Scripta, 45, 103–114. Morphology can be misleading in the representation of phylogenetic relationships, especially in simple organisms like cnidarians and particularly in hydrozoans. These suspension feeders are widely distributed in many marine ecosystems, and the family Aglaopheniidae Marktanner-Turneretscher, 1890 is among the most diverse and visible, especially on tropical coral reefs. The taxonomy of this family is based on morphological characters with emphasis on reproductive structures for the identification of genera. This study is the most comprehensive molecular phylogeny of the Aglaopheniidae to date, including six genera and 38 species, of which 13 were investigated for the first time and sampled on tropical coral reefs throughout the Indo-Pacific region. For newly sampled individuals, we sequenced the 16S rRNA, the nuclear locus comprising the complete ITS1-5.8S rRNA gene-ITS2 and the first intron of the calmodulin nuclear gene. Phylogenetic analyses of the data revealed and confirmed a general polyphyly, or doubtful monophyly, of all sampled genera in tropical regions based on both the mitochondrial and nuclear markers. Our results revealed that several morphological characters used today are unsuited to resolve phylogenetic relationships between species and genera, as well as the high phyletic diversity within this family. Future revision of the classification of this family will require extensive geographic sampling and the use of an integrative approach.
ISSN: 0300-3256

hal-01359414
https://hal.archives-ouvertes.fr/hal-01359414
DOI : 10.1111/zsc.12135

Éditeur(s) : HAL CCSD Nature Publishing Group
Résumé : International audience
Coral reefs are among the most species-rich and threatened ecosystems on Earth, yet the extent to which human stressors determine species occurrences, compared with biogeography or environmental conditions, remains largely unknown. With ever-increasing human-mediated disturbances on these ecosystems, an important question is not only how many species can inhabit local communities, but also which biological traits determine species that can persist (or not) above particular disturbance thresholds. Here we show that human pressure and seasonal climate variability are disproportionately and negatively associated with the occurrence of large-bodied and geographically small-ranging fishes within local coral reef communities. These species are 67% less likely to occur where human impact and temperature seasonality exceed critical thresholds, such as in the marine biodiversity hotspot: the Coral Triangle. Our results identify the most sensitive species and critical thresholds of human and climatic stressors, providing opportunity for targeted conservation intervention to prevent local extinctions.
ISSN: 2041-1723

hal-01282870
https://hal-univ-perp.archives-ouvertes.fr/hal-01282870
https://hal-univ-perp.archives-ouvertes.fr/hal-01282870/document
https://hal-univ-perp.archives-ouvertes.fr/hal-01282870/file/ncomms10491.pdf
DOI : 10.1038/ncomms10491

Éditeur(s) : HAL CCSD Nature Publishing Group
Résumé : International audience
Seabirds concentrate nutrients from large marine areas on their nesting islands playing an important ecological role in nutrient transfer between marine and terrestrial ecosystems. Here we investigate the role of guano on corals reefs across scales by analyzing the stable nitrogen isotopic (delta N-15) values of the scleractinian coral Pocillopora damicornis on fringing reefs around two Pacific remote islets with large seabird colonies. Marine stations closest to the seabird colonies had higher nitrate + nitrite concentrations compared to more distant stations. Coral and zooxanthellae delta N-15 values were also higher at these sites, suggesting that guano-derived nitrogen is assimilated into corals and contributes to their nitrogen requirements. The spatial extent of guano influence was however restricted to a local scale. Our results demonstrate that seabird-derived nutrients not only spread across the terrestrial ecosystem, but also affect components of the adjacent marine ecosystem. Further studies are now needed to assess if this nutrient input has a positive or negative effect for corals. Such studies on remote islets also open fresh perspectives to understand how nutrients affect coral reefs isolated from other anthropogenic stressors.
ISSN: 2045-2322

hal-01681575
https://hal.archives-ouvertes.fr/hal-01681575
DOI : 10.1038/s41598-017-03781-y

Éditeur(s) : HAL CCSD Cambridge University Press
Résumé : International audience
Genetic variation was examined in two complex cases of Indo-Pacific pygmy angelfishes (genus Centropyge; Pomacanthidae). The lemonpeel pygmy angelfish C. flavissima (Cuvier and Valenciennes) has a geographically disjunct Indian vs. Pacific distribution and the individuals from these two regions differ by their colour patterns. Previous research on C. flavissima has shown mitochondrial introgression from two related species, C. eibli in the eastern Indian Ocean and C. vrolikii in the Pacific Ocean. Using the 16S rDNA and the CO1 gene as phylogeographic markers, we found no mitochondrial haplotypes in common between Indian Ocean C. flavissima and C. eibli, confirming partial genetic isolation, albeit recent. Also, we found substantial genetic differences between Indian and Pacific C. flavissima populations at the nuclear ETS-2 intron locus. The Indian Ocean form of C. flavissima, thus geographically isolated by >2000 km distance from its Pacific Ocean counterpart, is described as a new species, Centropyge cocosensis sp. nov. Centropyge cocosensis sp. nov. differs in appearance from C. flavissima in having a conspicuous blue iris and a fainter, bluish eye ring. We also found that the yellow pygmy angelfish C. heraldi Woods and Schultz consists of two genetically distinct entities, one distributed widely in the northern tropical Indo-West Pacific, the other distributed in the southern Pacific Ocean. The name originally given to the blackfin pygmy angelfish, C. woodheadi Kuiter, is here resurrected to designate the latter.
EISSN: 1755-2672

hal-01340521
https://hal-univ-perp.archives-ouvertes.fr/hal-01340521
DOI : 10.1007/s12526-016-0509-y

Éditeur(s) : HAL CCSD Western Indian Ocean Marine Science Association
Résumé : International audience
Juan de Nova is one of the scattered islands known as Iles Eparses in the Mozambique Channel (Western Indian Ocean). Historically, they have been isolated from many anthropogenic influences which makes them ideal areas to study biodiversity for comparison with areas that are heavily impacted by urbanization and fishing. The programme BioReCie (Biodiversity, Resources and Conservation of Eparses Islands) undertook inventories of several marine groups, including echinoderms, which had hitherto not been assessed in Juan de Nova. A multidisciplinary team surveyed the reef slopes of the island using SCUBA to a depth of 25 m as well as the reef flats at low tide, collecting specimens and taking photos for identification. Sixty echinoderm species were found, with 51 occurring on the reef flats and in the lagoon and 22 on the reef slopes, comprising 21 species of Holothuroidea, 16 Ophiuroidea, 10 Echinoidea, 7 Asteroidea, and 6 Crinoidea. Commercial species of Holothuroidea, some of which are classified as endangered in the IUCN red list, i.e. Thelenota ananas and Holothuria nobilis, were present on the reef flats, reef slopes and in the lagoon of the island, indicating the value that protection has on biodiversity.
ISSN: 0856-860X

hal-01306709
http://hal.univ-reunion.fr/hal-01306709
http://hal.univ-reunion.fr/hal-01306709/document
http://hal.univ-reunion.fr/hal-01306709/file/A%20First%20Inventory%20of%20Echinodermata%20at%20Juan%20de%20Nova_hal.pdf

Éditeur(s) : HAL CCSD Elsevier
Résumé : International audience
We isolated and characterized 26 microsatellite loci for Macrorhynchia phoenicea (Busk, 1852), a rather common tropical hydrozoan from the Indo-Pacific. The number of alleles per locus ranged from 4 to 24. The observed heterozygosity ranged from 0.000 to 0.970 and the expected heterozygosity from 0.029 to 0.833. Ten loci were at HardyeWeinberg equilibrium. No pair of loci presented linkage disequilibrium. Transferability of up to 18 loci was positive across four other Aglaopheniidae species from different genera. These loci will be used in studying reef population connectivity for these particular species at the scale of the Indo-Pacific, a promising but little explored research field.
ISSN: 0305-1978

hal-01359419
https://hal.archives-ouvertes.fr/hal-01359419
DOI : 10.1016/j.bse.2015.08.011

Éditeur(s) : HAL CCSD Elsevier
Résumé : International audience
A comprehensive inventory of global biodiversity would be greatly improved by automating methods for species delimitation. The Automatic Barcode Gap Discovery method, the Poisson tree processes algorithm and the Generalized mixed Yule coalescent model have been proposed as means of increasing the rate of biodiversity description using single locus data. We applied these methods to explore the diversity within the Aglaopheniidae, a hydrozoan family with many species widely distributed across tropical and tem perate oceans. Our analyses revealed widespread cryptic diversity in this family, almost half of the morpho species presenting several independent evolutionary lineages, as well as support for cases of synonymy. For two common species of this family, Lytocarpia brevirostris and Macrorhynchia phoenicea, we compared the outputs to clustering analyses based on microsatellite data and to nuclear gene phylo genies. For L. brevirostris, microsatellite data were congruent with results of the species delimitation methods, revealing the existence of two cryptic species with Indo Pacific distribution. For M. phoenicea, all analyses confirmed the presence of two cryptic species within the South Western Indian Ocean. Our study suggests that the diversity of Aglaopheniidae might be much higher than assumed, likely related to low dispersal capacities. Sequence based species delimitation methods seem highly valuable to reveal cryptic diversity in hydrozoans; their application in an integrative framework will be very useful in describing the phyletic diversity of these organisms.
ISSN: 1055-7903

hal-01359407
https://hal.archives-ouvertes.fr/hal-01359407
https://hal.archives-ouvertes.fr/hal-01359407/document
https://hal.archives-ouvertes.fr/hal-01359407/file/Postaire-etal2016MolPhylEvol_sp_delim_hydraires_HAL.pdf
DOI : 10.1016/j.ympev.2016.08.013

Éditeur(s) : HAL CCSD Magnolia Press
Résumé : International audience
Despite their importance in marine biodiversity, invertebrates are far less studied than vertebrates. Given the current globalbiodiversity crisis and insufficient taxonomic resources, sustained efforts need to be undertaken to assess species diversity,especially in the highly threatened ‘biodiversity hotspots’. Réunion is a young volcanic island lying in the Mascarene Islands(south-western Indian Ocean, SWIO), a marine biodiversity hotspot. A substantial sampling effort was conductedaround Réunion Island to document shallow water reef-associated ophiuroid (brittle-stars) diversity, a class recognised asthe most diverse among echinoderms. A total of 33 species were documented, increasing the known species richness ofthe island by 56%. Findings include 15 new records for Réunion, 11 for the Mascarene Islands and 8 for the Indian Ocean.The most diverse family was Ophiocomidae, a family of large, abundant and conspicuous tropical species. Even in thiswell studied family, a new species was revealed by this survey. Morphological variants together with DNA sequence variationswithin several species revealed cryptic species. We compared our results with the known fauna of other MascareneIslands and discuss biogeographic implications for the region.
ISSN: 1175-5326

hal-01327053
https://hal-univ-perp.archives-ouvertes.fr/hal-01327053
DOI : 10.11646/zootaxa.4098.2.4

Éditeur(s) : HAL CCSD Springer Verlag
Résumé : International audience
Coral reefs are increasingly being altered by a myriad of anthropogenic activities and natural disturbances. Long-term studies offer unique opportunities to understand how multiple and recurrent disturbances can influence coral reef resilience and long-term dynamics. While the long-term dynamics of coral assemblages have been extensively documented, the long-term dynamics of coral reef fish assemblages have received less attention. Here, we describe the changes in fish assemblages on Tiahura reef, Moorea, from 1979 to 2011. During this 33-yr period, Tiahura was exposed to multiple disturbances (crown-of-thorns seastar outbreaks and cyclones) that caused recurrent declines and recoveries of coral cover and changes in the dominant coral genera. These shifts in coral composition were associated with long-term cascading effects on fish assemblages. The composition and trophic structure of fish assemblages continuously shifted without returning to their initial composition, whereas fish species richness remained stable, albeit with a small increase over time. We detected nonlinear responses of fish density when corals were most degraded. When coral cover dropped below 10 % following a severe crown-of-thorns sea star outbreak, the density of most fish trophic groups sharply decreased. Our study shows that historical contingency may potentially be an important but largely underestimated factor explaining the contemporary structure of reef fish assemblages and suggests that temporal stability in their structure and function should not necessarily be the target of management strategies that aim at increasing or maintaining coral reef resilience.
ISSN: 0722-4028

hal-01282725
https://hal-univ-perp.archives-ouvertes.fr/hal-01282725
DOI : 10.1007/s00338-015-1371-2

Éditeur(s) : HAL CCSD Springer
Résumé : International audience
Total genomic DNA of eight colonies for each of the two species, Acropora muricata and Porites lutea, sampled on the west coast of Reunion Island, was isolated using DNeasy Blood & Tissue kit (Qiagen™) following the manufacturer’s instructions and sent to GenoScreen, Lille, France (www.genoscreen.fr).
ISSN: 1877-7252

hal-01254248
https://hal.archives-ouvertes.fr/hal-01254248
https://hal.archives-ouvertes.fr/hal-01254248/document
https://hal.archives-ouvertes.fr/hal-01254248/file/G%C3%A9lin%20et%20al.%20-%202015%20-%20Isolation%20and%20characterization%20of%2022%20microsatellit_hal.pdf
DOI : 10.1007/s12686-015-0493-8

Éditeur(s) : HAL CCSD Royal Society
Résumé : Coral bleaching events are predicted to occur more frequently in the coming decades with global warming. The susceptibility of corals to bleaching during thermal stress episodes depends on many factors, including the magnitude of thermal stress and irradiance. The interactions among these two factors, and in particular with ultra-violet radiation (UVR), the most harmful component of light, are more complex than assumed, and are not yet well understood. This paper explores the individual and combined effects of temperature and UVR on the metabolism of Acropora muricata, one of the most abundant coral species worldwide. Particulate and dissolved organic matter (POM/DOM) fluxes and organic matter (OM) degradation by the mucus-associated bacteria were also monitored in all conditions. The results show that UVR exposure exacerbated the temperature-induced bleaching, but did not affect OM fluxes, which were only altered by seawater warming. Temperature increase induced a shift from POM release and DOM uptake in healthy corals to POM uptake and DOM release in stressed ones. POM uptake was linked to a significant grazing of pico- and nanoplankton particles during the incubation, to fulfil the energetic requirements of A. muricata in the absence of autotrophy. Finally, OM degradation by mucus-associated bacterial activity was unaffected by UVR exposure, but significantly increased under high temperature. Altogether, our results demonstrate that seawater warming and UVR not only affect coral physiology, but also the way corals interact with the surrounding seawater, with potential consequences for coral reef biogeochemical cycles and food webs.
ISSN: 2046-6390

hal-01606454
https://hal.archives-ouvertes.fr/hal-01606454
DOI : 10.1242/bio.026757
PRODINRA : 406580
PUBMED : 28811302

Éditeur(s) : HAL CCSD
Résumé : Designing biodiversity conservation plans requires knowledge on the biogeographic distribution of taxabut also accurate estimates of species richness and diversification processes. However, measuring the phyleticrichness can be biased by the use of inappropriate taxonomical characters, leading to erroneous speciesdelimitation and diversity estimates.This work explores the phyletic richness at several taxonomic levels (generic, specific and intraspecific) ofthe hydrozoan family Aglaopheniidae (Marktanner-Turneretscher, 1890), with a particular focus on the South-Western Indian Ocean. Firstly, using several newly constructed phylogenies based on mitochondrial andnuclear markers, this study reveals that the phyletic diversity of this family is at underestimated by at least 50%:all studied genera are polyphyletic or with doubtful monophyletic status. Then, using several speciesdelimitation methods based on molecular markers, it sheds light on the richness of cryptic diversity of thisfamily, enlightening the potential of using an integrative taxonomic approach on these morphologically simpleorganisms. Finally, the population genetics of an Aglaopheniidae brooding species shows a high populationsstructuring with pervasive pattern of isolation by distance at several geographic scales (several to thousands ofkilometres), implying a potentially high cryptic diversity existing in this family.The results of this work provide new insights on Aglaopheniidae diversity, underlining the potentialinfluence of reproductive mode on the phyletic diversity and diversification processes of brooding hydrozoanbrooders. This thesis further highlights the relevance of using several complementary
La conservation et la gestion sur le long terme de la biodiversité nécessitent une connaissance de larépartition des taxons, mais également une estimation précise de leur diversité spécifique ainsi que desprocessus de spéciation ayant permis leur formation. Cependant, la mesure de la richesse phylétique peut êtrebiaisée par l’utilisation de caractères taxinomiques ne permettant pas de délimiter les espèces de manièreappropriée.Ce travail de thèse propose d’explorer la diversité phylétique à plusieurs niveaux taxinomiques(générique, spécifique et intra-spécifique) des Aglaopheniidae, une famille d’hydrozoaires, notamment présentedans le Sud-Ouest de l’océan Indien. Dans un premier temps, en utilisant des phylogénies basées sur plusieursmarqueurs (mitochondriaux et nucléaires), ce travail démontre que la diversité phylétique de cette famille est,au minimum, sous-estimée de moitié: tous les genres de la famille sont polyphyléthiques ou présentent un statutmonophylétique restant à confirmer. Dans un deuxième temps, l’utilisation de méthodes de délimitationd’espèces basées sur des données moléculaires met en évidence la diversité cryptique très élevée des morphoespècesétudiées, révélant l’intérêt potentiel des protocoles de taxinomie intégrative chez les organismesmorphologiquement simples. Enfin, l’étude de génétique des populations d’une espèce incubatriced’Aglaopheniidae révèle l’importance de la structuration des populations et de l’isolement par la distance chezcette espèce à plusieurs échelles géographiques (de quelques kilomètres à plusieurs milliers), impliquant unepotentielle diversité cryptique extrêmement élevée chez cette famille.L’ensemble des connaissances acquises lors de ce travail de thèse fournit un nouveau regard sur ladiversité de la famille des Aglaopheniidae, soulignant le potentiel impact du cycle de reproduction sur ladiversité phylétique et les processus de spéciation des hydrozoaires incubateurs. Cette thèse met en évidence lapertinence de l’utilisation de plusieurs procédures complémentaires de délimitation d’espèces pour étudier ladiversité des organismes morphologiquement simples.
https://hal.archives-ouvertes.fr/tel-01359424

tel-01359424
https://hal.archives-ouvertes.fr/tel-01359424
https://hal.archives-ouvertes.fr/tel-01359424/document
https://hal.archives-ouvertes.fr/tel-01359424/file/These%20manuscrit%20final.pdf