Unveiling hidden species' diversity within Southern Ocean Iphimediidae (Crustacea: Amphipoda) through DNA and 3D-geometric morphometrics, with the description of 10 new species - 2026
Unveiling hidden species' diversity within Southern Ocean Iphimediidae (Crustacea: Amphipoda) through DNA and 3D-geometric morphometrics, with the description of 10 new species
Antarctica; COI mtDNA; molecular phylogeny; morphometrics; scanning electron microscopy; species delineation; taxonomy; Ecology, Evolution, Behavior and Systematics; Animal Science and Zoology
Abstract :
[en] The Antarctic shelf benthos is threatened by climate-related environmental changes and anthropogenic stressors. A baseline knowledge of biodiversity and species' distribution ranges is essential for effective monitoring and conservation. Here, we integrate DNA-based species' delimitation methods with morphological analyses to explore species' diversity within Antarctic Iphimediidae. Our results reveal that 10 nominal species are complexes of multiple species, most of which can be distinguished by small but consistent morphological differences. We formally describe 10 of these new species: Stegopanoploea brevidentata sp. nov., Maxilliphimedia acutilobata sp. nov., Maxilliphimedia oliveri sp. nov., Echiniphimedia spinosior sp. nov., Echiniphimedia maxima sp. nov., Iphimediella longidentata sp. nov., Iphimediella brachyodonta sp. nov., Iphimediella longilobata sp. nov., Labriphimedia adeliae sp. nov., and Labriphimedia anneninae sp. nov.. Most previously recorded circum-Antarctic iphimediid species are found to consist of regionally distributed species. Furthermore, we apply 3D-geometric morphometrics on the Gnathiphimedia sexdentata complex to investigate whether 'cryptic' species can be differentiated by variation in continuous morphological traits. This method provides additional diagnostic characters for the morphological identification of two G. sexdentata clades. This integrative taxonomy study increases the number of nominal Antarctic iphimediid species from 39 to 49, with 14 additional putative species requiring further study for formal description.
Research Center/Unit :
FOCUS - Freshwater and OCeanic science Unit of reSearch - ULiège
Verheye, Marie ; Université de Liège - ULiège > Département de Biologie, Ecologie et Evolution > Ecologie évolutive ; Operational Directorate Natural Environments, Royal Belgian Institute of Natural Sciences (RBINS), Brussels, Belgium
Backeljau, Thierry ; Royal Belgian Institute of Natural Sciences (RBINS), Brussels, Belgium
D'Acoz, Cédric d'Udekem ; Royal Belgian Institute of Natural Sciences (RBINS), Brussels, Belgium
Frederich, Bruno ; Université de Liège - ULiège > Freshwater and OCeanic science Unit of reSearch (FOCUS)
Herrel, Anthony ; Mécanismes Adaptatifs et Evolution, UMR 7179, Muséum national d'Histoire naturelle (MNHN), Paris, France ; Department of Biology, Evolutionary Morphology of Vertebrates, Ghent University, Ghent, Belgium ; Functional Morphology Laboratory, Department of Biology, University of Antwerp, Antwerp, Belgium ; Naturhistorisches Museum Bern, Bern, Switzerland
Lepoint, Gilles ; Université de Liège - ULiège > Département de Biologie, Ecologie et Evolution
Schön, Isa ; Operational Directorate Natural Environments, Royal Belgian Institute of Natural Sciences (RBINS), Brussels, Belgium
Language :
English
Title :
Unveiling hidden species' diversity within Southern Ocean Iphimediidae (Crustacea: Amphipoda) through DNA and 3D-geometric morphometrics, with the description of 10 new species
Adams DC, Otárola-Castillo E. geomorph: an R package for the collection and analysis of geometric morphometric shape data. Methods in Ecology and Evolution 2013; 4: 393 9. 10.1111/2041-210x.12035
Allcock AL, Strugnell JM. Southern Ocean diversity: new paradigms from molecular ecology. Trends in Ecology & Evolution 2012; 27: 520 8. 10.1016/j.tree.2012.05.009
Allcock AL, Barratt I, Eleaume M et al. Cryptic speciation and the circumpolarity debate: a case study on endemic Southern Ocean octopuses using the COI barcode of life. Deep Sea Research Part II: Topical Studies in Oceanography 2011; 58: 242 9. 10.1016/j.dsr2.2010.05.016
Amsler MO, Mcclintock JB, Amsler CD et al. An evaluation of sponge-associated amphipods from the Antarctic Peninsula. Antarctic Science 2009; 21: 579 89. 10.1017/s0954102009990356
Asochakov IA. Technique for measuring body length of amphipods. Hydrobiological Journal 1994; 30: 107.
Barnard KH. Amphipoda. British Antarctic (Terra Nova) Expedition 1910, Natural History Reports 1930; 5: 1 326. 10.5962/bhl.part.27664
Barnard JL. Keys to the Hawaiian Marine Gammaridea, 0-30 Meters, Vol. 58. Washington: Smithsonian Contributions to Zoology, 1971.
Bellan-Santini D. Invertébrés marins des XIIème et XVème Expéditions Antarctiques Françaises en Terre Adélie. 10. Amphipodes Gammariens. Tethys 1972; 4: 157 238.
Bentley MJ, Cofaigh CO, Anderson JB et al. A community-based geological reconstruction of Antarctic Ice Sheet deglaciation since the Last Glacial Maximum. Quaternary Science Reviews 2014; 100: 1 9.
Blanco-Bercial L, Cornils A, Copley N et al. DNA barcoding of marine copepods: assessment of analytical approaches to species identification. PLoS Currents 2014; 6: ecurrents.tol.cdf8b74881f87e3b01d56b43791626d2. 10.1371/currents.tol.cdf8b74881f87e3b01d56b43791626d2
Bookstein FL. Morphometric Tools for Landmark Data: Geometry and Biology. Cambridge: Cambridge University Press, 1991.
Botton-Divet L, Cornette R, Fabre AC et al. Morphological analysis of long bones in semi-aquatic mustelids and their terrestrial relatives. Integrative and Comparative Biology 2016; 56: 1298 309. 10.1093/icb/icw124
Brandão SN, Sauer J, Schön I. Circumantarctic distribution in Southern Ocean benthos? A genetic test using the genus Macroscapha (Crustacea, Ostracoda) as a model. Molecular Phylogenetics and Evolution 2010; 55: 1055 69. 10.1016/j.ympev.2010.01.014
Brasier MJ, Wiklund H, Neal L et al. DNA barcoding uncovers cryptic diversity in 50% of deep-sea Antarctic polychaetes. Royal Society Open Science 2016; 3: 1 19.
Burridge AK, Van Der Hulst R, Goetze E et al. Assessing species boundaries in the open sea: an integrative taxonomic approach to the pteropod genus Diacavolinia. Zoological Journal of the Linnean Society 2019; 187: 1016 40. 10.1093/zoolinnean/zlz049
Carstens BC, Pelletier TA, Reid NM et al. How to fail at species' delimitation. Molecular Ecology 2013; 22: 4369 83. 10.1111/mec.12413
Chen Y, Ye W, Zhang Y et al. High speed BLASTN: an accelerated MegaBLAST search tool. Nucleic Acids Research 2015; 43: 7762 8. 10.1093/nar/gkv784
Chevreux E. Diagnoses d'amphipodes nouveaux. Deuxième expédition dans l'Antarctique, dirigée par le Dr. Charcot, 1908-1910. Bulletin du Muséum National d'Histoire Naturelle 1912; 18: 208 18.
Chevreux E. Amphipodes. Deuxième Expédition Antarctique Française (1908-1910). Sciences Naturelles: Documents Scientifiques 1913; 77: 186.
Clarke A, Crame JA. The Southern Ocean benthic fauna and climate change: a historical perspective. Philosophical Transactions of the Royal Society of London, Series B: Biological Sciences 1992; 338: 299 309.
Clarke A, Johnston NM. Antarctic marine benthic diversity. In: Gibson RN, Atkinson RJA (eds), Oceanography and Marine Biology. London and New York: Taylor & Francis, 2003, 47 114.
Clarke A, Aronson RB, Crame JA et al. Evolution and diversity of the benthic fauna of the Southern Ocean continental shelf. Antarctic Science 2004; 16: 559 68. 10.1017/s0954102004002329
Clement M, Posada D, Crandall KA. TCS: a computer program to estimate gene genealogies. Molecular Ecology 2000; 9: 1657 9. 10.1046/j.1365-294x.2000.01020.x
Coleman CO. On the nutrition of two Antarctic Acanthonotozomatidae (Crustacea: Amphipoda): gut contents and functional morphology of mouthparts. Polar Biology 1989a; 9: 287 94. 10.1007/bf00287425
Convey P, Bindschadler R, Di Prisco G et al. Antarctic climate change and the environment. Antarctic Science 2009; 21: 541 63.
Convey P, Bowman V, Chown SL, et al. Ice bound Antarctica: biotic consequences of the shift from a temperate to a polar climate. In: Hoorn C, Perrigo A, Antonelli A (eds), Mountains, Climate and Biodiversity. Oxford UK: John Wiley & Sons, 2018, 355 73.
Corrigan LJ, Horton T, Fotherby H et al. Adaptive evolution of deep-sea amphipods from the superfamily Lysiassanoidea in the North Atlantic. Evolutionary Biology 2014; 41: 154 65. 10.1007/s11692-013-9255-2
Cummings VJ, Thrush SF, Chiantore M et al. Macrobenthic communities of the north-western Ross Sea shelf: links to depth, sediment characteristics and latitude. Antarctic Science 2010; 22: 793 804. 10.1017/s0954102010000489
Dauby P, Scailteur Y, De Broyer C. Trophic diversity within the eastern Weddell Sea amphipod community. Hydrobiologia 2001; 443: 69 86.
De Broyer C. Recherches sur la systématique et l'évolution des crustacés amphipodes gammarides antarctiques et subantarctiques. D.Phil. Thesis, Université Catholique de Louvain, 1983.
De Broyer C, Danis B. How many species in the Southern Ocean? Towards a dynamic inventory of the Antarctic marine species. Deep Sea Research Part II: Topical Studies in Oceanography 2011; 58: 5 17. 10.1016/j.dsr2.2010.10.007
De Broyer C, Jażdżewska A. Biogeographic patterns of Southern Ocean benthic amphipods. In: De Broyer C, Koubbi P et al.. (ed.), Biogeographic Atlas of the Southern Ocean. Cambridge: Scientific Committee on Antarctic Research, 2014, 155 65.
De Broyer C, Scailteur Y, Chapelle G et al. Diversity of epibenthic habitats of gammaridean amphipods in the eastern Weddell Sea. Polar Biology 2001; 24: 744 53. 10.1007/s003000100276
De Broyer C, Jazdzewski K, Dauby P. Chapter 32. Biodiversity patterns in the Southern Ocean: lessons from Crustacea. In: Huiskes AHL, Gieskes WWC, Rozema J et al.. (eds), Antarctica in a Global Context. Leiden: Backhuys, 2003, 201 14.
Dellicour S, Flot JF. The hitchhiker's guide to single-locus species' delimitation. Molecular Ecology Resources 2018; 18: 1234 46. 10.1111/1755-0998.12908
De Queiroz K. Species concepts and species' delimitation. Systematic Biology 2007; 56: 879 86. 10.1080/10635150701701083
Dietz L, Arango CP, Dömel JS et al. Regional differentiation and extensive hybridization between mitochondrial clades of the Southern Ocean giant sea spider Colossendeis megalonyx. Royal Society Open Science 2015; 2: 140424 15. 10.1098/rsos.140424
Ezard T, Fujisawa T, Barraclough TG. splits: SPecies' LImits by Threshold Statistics. R Package v.1.0-14/r31, 2009. Vienna, Austria: R-Forge. Available at: https://r-forge.r-project.org/projects/splits/
Fišer Z, Altermatt F, Zakšek V et al. Morphologically cryptic amphipod species are 'ecological clones' at regional but not at local scale: a case study of four Niphargus species. PLoS One 2015; 10: e0134384. 10.1371/journal.pone.0134384
Fujisawa T, Barraclough TG. Delimiting species using single-locus data and the Generalized Mixed Yule Coalescent approach: a revised method and evaluation on simulated data sets. Systematic Biology 2013; 62: 707 24. 10.1093/sysbio/syt033
Funk DJ, Omland KE. Species-level paraphyly and polyphyly: frequency, causes, and consequences, with insights from animal mitochondrial DNA. Annual Review of Ecology, Evolution, and Systematics 2003; 34: 397 423. 10.1146/annurev.ecolsys.34.011802.132421
Golledge NR, Fogwill CJ, Mackintosh AN et al. Dynamics of the last glacial maximum Antarctic ice-sheet and its response to ocean forcing. Proceedings of the National Academy of Sciences of the United States of America 2012; 109: 16052 6. 10.1073/pnas.1205385109
Graeve M, Dauby P, Scailteur Y. Combined lipid, fatty acid and digestive tract content analyses: a penetrating approach to estimate feeding modes of Antarctic amphipods. Polar Biology 2001; 24: 853 62.
Grant RA, Griffiths HJ, Steinke D et al. Antarctic DNA barcoding; a drop in the ocean? Polar Biology 2011; 34: 775 80. 10.1007/s00300-010-0932-7
Griffiths HJ. Antarctic marine biodiversity - what do we know about the distribution of life in the Southern Ocean? PLoS One 2010; 5: e11683. 10.1371/journal.pone.0011683
Gunz P, Mitteroecker P, Bookstein FL. Semilandmarks in three dimensions. In: Slice DE, (ed.), Modern Morphometrics in Physical Anthropology. New York: Kluwer Academic/Plenum Publishers, 2005, 73 98.
Gutt J, Piepenburg D. Scale-dependent impact on diversity of Antarctic benthos caused by grounding of icebergs. Marine Ecology Progress Series 2003; 253: 77 83. 10.3354/meps253077
Gutt J, Sirenko BI, Smirnov IS et al. How many macrozoobenthic species might inhabit the Antarctic shelf? Antarctic Science 2004; 16: 11 6. 10.1017/s0954102004001750
Gutt J, Barratt I, Domack E et al. Biodiversity change after climate-induced ice-shelf collapse in the Antarctic. Deep Sea Research Part II: Topical Studies in Oceanography 2011; 58: 74 83. 10.1016/j.dsr2.2010.05.024
Gutt J, Barnes DK, Lockhart SJ et al. Antarctic macrobenthic communities: a compilation of circumpolar information. Nature Conservation 2013; 4: 1 13. 10.3897/natureconservation.4.4499
Gutt J, Isla E, Xavier JC et al. Antarctic ecosystems in transition - life between stresses and opportunities. Biological Reviews 2021; 96: 798 821.
Havermans C, Nagy ZT, Sonet G et al. DNA barcoding reveals new insights into the diversity of Antarctic species of Orchomene sensu lato (Crustacea: Amphipoda: Lysianassoidea). Deep Sea Research Part II: Topical Studies in Oceanography 2011; 58: 230 41. 10.1016/j.dsr2.2010.09.028
Havermans C, Sonet G, d'Udekem d'Acoz C et al. Genetic and morphological divergences in the cosmopolitan deep-sea amphipod Eurythenes gryllus reveal a diverse abyss and a bipolar species. PLoS One 2013; 8: e74218. 10.1371/journal.pone.0074218
Held C. Molecular evidence for cryptic speciation within the widespread Antarctic crustacean Ceratoserolis trilobitoides (Crustacea, Isopoda). In: Huiskes AHL, Gieskes WWC, Rozema J et al.. (eds), Antarctic Biology in a Global Context. Leiden: Backhuys, 2003, 135 9.
Hemery LG, Eléaume M, Roussel V et al. Comprehensive sampling reveals circumpolarity and sympatry in seven mitochondrial lineages of the Southern Ocean crinoid species Promachocrinus kerguelensis (Echinodermata). Molecular Ecology 2012; 21: 2502 18. 10.1111/j.1365-294X.2012.05512.x
Hou Z, Fu J, Li S. A molecular phylogeny of the genus Gammarus (Crustacea: Amphipoda) based on mitochondrial and nuclear gene sequences. Molecular Phylogenetics and Evolution 2007; 45: 596 611. 10.1016/j.ympev.2007.06.006
Hupało K, Copila-Ciocianu D, Leese F et al. Morphology, nuclear SNPs and mate selection reveal that COI barcoding overestimates species' diversity in a Mediterranean freshwater amphipod by an order of magnitude. Cladistics 2023; 39: 129 43.
ICZN. International Code of Zoological Nomenclature, 4th edn. London: The International Trust for Zoological Nomenclature 1999 c/o. The Natural History Museum, 1999, 1 124.
Jackson DA. Stopping rules in principal components analysis: a comparison of heuristical and statistical approaches. Ecology 1993; 74: 2204 14. 10.2307/1939574
Janosik AM, Halanych KM. Unrecognized Antarctic biodiversity: a case study of the genus Odontaster (Odontasteridae; Asteroidea). Integrative and Comparative Biology 2010; 50: 981 92. 10.1093/icb/icq119
Joly S, Stevens MI, Van Vuuren BJ. Haplotype networks can be misleading in the presence of missing data. Systematic Biology 2007; 56: 857 62. 10.1080/10635150701633153
Kapli P, Lutteropp S, Zhang J et al. Multi-rate Poisson tree processes for single-locus species' delimitation under maximum likelihood and Markov chain Monte Carlo. Bioinformatics 2017; 33: 1630 8. 10.1093/bioinformatics/btx025
Karanovic T, Bláha M. Taming extreme morphological variability through coupling of molecular phylogeny and quantitative phenotype analysis as a new avenue for taxonomy. Scientific Reports 2019; 9: 2429. 10.1038/s41598-019-38875-2
Karanovic T, Djurakic M, Eberhard SM. Cryptic species or inadequate taxonomy? Implementation of 2D geometric morphometrics based on integumental organs as landmarks for delimitation and description of copepod taxa. Systematic Biology 2016; 65: 304 27. 10.1093/sysbio/syv088
Katoh K, Standley DM. MAFFT multiple sequence alignment software version 7: improvements in performance and usability. Molecular Biology and Evolution 2013; 30: 772 80. 10.1093/molbev/mst010
King RA, Leys R. The Australian freshwater amphipods Austrochiltonia australis and Austrochiltonia subtenuis (Amphipoda: Talitroidea: Chiltoniidae) confirmed and two new cryptic Tasmanian species revealed using a combined molecular and morphological approach. Invertebrate Systematics 2011; 25: 171 96. 10.1071/is10035
Klages M, Gutt J. Comparative studies on the feeding behaviour of high Antarctic amphipods (Crustacea) in laboratory. Polar Biology 1990; 11: 73 9.
Klarner B, Maraun M, Scheu S. Trophic diversity and niche partitioning in a species rich predator guild-Natural variations in stable isotope ratios (13C/12C, 15N/14N) of mesostigmatid mites (Acari, Mesostigmata) from Central European beech forests. Soil Biology and Biochemistry 2013; 57: 327 33. 10.1016/j.soilbio.2012.08.013
Knowlton N. Sibling species in the sea. Annual Review of Ecology and Systematics 1993; 24: 189 216. 10.1146/annurev.ecolsys.24.1.189
Lanfear R, Calcott B, Ho SY et al. PartitionFinder: combined selection of partitioning schemes and substitution models for phylogenetic analyses. Molecular Biology and Evolution 2012; 29: 1695 701. 10.1093/molbev/mss020
Lau SC, Wilson NG, Silva CN et al. Detecting glacial refugia in the Southern Ocean. Ecography 2020; 43: 1639 56.
Layeghi Y, Momtazi F, Yazdi AB et al. An integrated taxonomic approach, using geometric morphometric methods, reveals the cryptic diversity of Parhyale darvishi Momtazi & Maghsoudlou, 2016 (Crustacea: Amphipoda: Hyalidae). Zoologischer Anzeiger 2022; 299: 96 105. 10.1016/j.jcz.2022.05.009
Linse K, Cope T, Lörz AN et al. Is the Scotia Sea a centre of Antarctic marine diversification? Some evidence of cryptic speciation in the circum-Antarctic bivalve Lissarca notorcadensis (Arcoidea: Philobryidae). Polar Biology 2007; 30: 1059 68. 10.1007/s00300-007-0265-3
Loerz A, Maas E, Linse K et al. Do circum-Antarctic species exist in peracarid Amphipoda? A case study in the genus Epimeria Costa, 1851 (Crustacea, Peracarida, Epimeriidae). ZooKeys 2009; 18: 91 128. 10.3897/zookeys.18.103
Luo A, Ling C, Ho SY et al. Comparison of methods for molecular species' delimitation across a range of speciation scenarios. Systematic Biology 2018; 67: 830 46.
Mace GM, Collar NJ, Gaston KJ et al. Quantification of extinction risk: IUCN's system for classifying threatened species. Conservation Biology 2008; 22: 1424 42. 10.1111/j.1523-1739.2008.01044.x
Mahon AR, Arango CP, Halanych KM. Genetic diversity of Nymphon (Arthropoda: Pycnogonida: Nymphonidae) along the Antarctic Peninsula with a focus on Nymphon australe Hodgson 1902. Marine Biology 2008; 155: 315 23. 10.1007/s00227-008-1029-5
Malekmohammad K, Khalaji-Pirbalouty V, Oraei H et al. Identifying closely related species of the genus Gammarus (Crustacea, Amphipoda) using geometric morphometrics. Iranian Journal of Animal Biosystematics 2021; 17: 137 46.
Marchiori AB, Bartholomei-Santos ML, Santos S. Intraspecific variation in Aegla longirostri (Crustacea: Decapoda: Anomura) revealed by geometric morphometrics: evidence for ongoing speciation? Biological Journal of the Linnean Society 2014; 112: 31 9. 10.1111/bij.12256
Maroni PJ, Baker BJ, Moran AL et al. One Antarctic slug to confuse them all: the underestimated diversity of Doris kerguelenensis. Invertebrate Systematics 2022; 36: 419 35. 10.1071/is21073
McLaughlin PA. Comparative Morphology of Recent Crustacea. San Francisco: W.H. Freeman, 1980, 1 177.
Michel LN, Danis B, Dubois P et al. Increased sea ice cover alters food web structure in East Antarctica. Scientific Reports 2019; 9: 8062. 10.1038/s41598-019-44605-5
Michel LN, Nyssen FL, Dauby P et al. Can mandible morphology help predict feeding habits in Antarctic amphipods? Antarctic Science 2020; 32: 496 507. 10.1017/s0954102020000395
Miller MA, Pfeiffer W, Schwartz T. Creating the CIPRES Science Gateway for inference of large phylogenetic trees. In: 2010 Gateway Computing Environments Workshop (GCE). IEEE, 2010, 1 8.
Misof B, Misof K. A Monte Carlo approach successfully identifies randomness in multiple sequence alignments: a more objective means of data exclusion. Systematic Biology 2009; 58: 21 34. 10.1093/sysbio/syp006
Monaghan MT, Wild R, Elliot M et al. Accelerated species inventory on Madagascar using coalescent-based models of species delineation. Systematic Biology 2009; 58: 298 311. 10.1093/sysbio/syp027
Moore PG, Wong YM. Observations on the life history of Orchomene nanus (Krøyer) (Amphipoda: Lysianassoidea) at Millport, Scotland as deduced from baited trapping. Journal of Experimental Marine Biology and Ecology 1996; 195: 53 70. 10.1016/0022-0981(95)00094-1
Mutanen M, Pretorius E. Subjective visual evaluation vs. traditional and geometric morphometrics in species' delimitation: a comparison of moth genitalia. Systematic Entomology 2007; 32: 371 86. 10.1111/j.1365-3113.2006.00372.x
Nicholls E. The Amphipoda Gammaridea. Australasian Antarctic Expedition 1911 - 14. Scientific Reports. Series C. Zoology and Botany 1938; 2: 1 145.
Nyssen F, Brey T, Lepoint G et al. A stable isotope approach to the eastern Weddell Sea trophic web: focus on benthic amphipods. Polar Biology 2002; 25: 280 7. 10.1007/s00300-001-0340-0
Nyssen F, Brey T, Dauby P et al. Trophic position of Antarctic amphipods - enhanced analysis by a 2-dimensional biomarker assay. Marine Ecology Progress Series 2005; 300: 135 45. 10.3354/meps300135
Otto JC, Wilson KJ. Assessment of the usefulness of ribosomal 18S and mitochondrial COI sequences in Prostigmata phylogeny. In: Acarology: Proceedings of the 10th International Congress. Melbourne: CSIRO Publishing, 2001.
Padial JM, Miralles A, De la Riva I et al. The integrative future of taxonomy. Frontiers in Zoology 2010; 7: 16 4. 10.1186/1742-9994-7-16
Paradis E, Claude J, Strimmer K. APE: analyses of phylogenetics and evolution in R language. Bioinformatics 2004; 20: 289 90. 10.1093/bioinformatics/btg412
Parzen E. Extraction and detection problems and reproducing kernel Hilbert spaces. Journal of the Society for Industrial and Applied Mathematics, Series A: Control 1962; 1: 35 62. 10.1137/0301004
Peck LS. Antarctic marine biodiversity: adaptations, environments and responses to change. Oceanography and Marine Biology: An Annual Review 2018; 56: 2 133.
Pilar Cabezas M, Cabezas P, Machordom A et al. Hidden diversity and cryptic speciation refute cosmopolitan distribution in Caprella penantis (Crustacea: Amphipoda: Caprellidae). Journal of Zoological Systematics and Evolutionary Research 2013; 51: 85 99. 10.1111/jzs.12010
Pollard D, DeConto RM. Modelling West Antarctic ice sheet growth and collapse through the past five million years. Nature 2009; 458: 329 32. 10.1038/nature07809
Pons J, Barraclough TG, Gomez-Zurita J et al. Sequence-based species' delimitation for the DNA taxonomy of undescribed insects. Systematic Biology 2006; 55: 595 609. 10.1080/10635150600852011
Post E, Bhatt US, Bitz CM et al. Ecological consequences of sea-ice decline. Science 2013; 341: 519 24. 10.1126/science.1235225">https://doi.org/10.1126/science.1235225
Powles H, Bradford MJ, Bradford RG et al. Assessing and protecting endangered marine species. ICES Journal of Marine Science 2000; 57: 669 76.
Puillandre N, Lambert A, Brouillet S et al. ABGD, Automatic Barcode Gap Discovery for primary species' delimitation. Molecular Ecology 2012; 21: 1864 77. 10.1111/j.1365-294X.2011.05239.x
Raguá-Gil JM, Gutt J, Clarke A et al. Antarctic shallow-water mega-epibenthos: shaped by circumpolar dispersion or local conditions? Marine Biology 2004; 144: 829 39.
Rambaut A, Drummond AJ, Xie D et al. Posterior summarization in Bayesian phylogenetics using Tracer 1.7. Systematic Biology 2018; 67: 901 4. 10.1093/sysbio/syy032
Rannala B, Yang Z. Species Delimitation. Self published, 2020.
Rathke H. Beiträge zur Fauna Norwegens. Nova Acta Academiae Caesareae Leopoldino-Carolinae Naturae Curiosorum, Breslau & Bonn 1843; 20: 1 264.
Raupach MJ, Malyutina M, Brandt A et al. Molecular data reveal a highly diverse species flock within the munnopsoid deep-sea isopod Betamorpha fusiformis (Barnard, 1920) (Crustacea: Isopoda: Asellota) in the Southern Ocean. Deep Sea Research Part II: Topical Studies in Oceanography 2007; 54: 1820 30. 10.1016/j.dsr2.2007.07.009
Riddle MJ, Craven M, Goldsworthy PM et al. A diverse benthic assemblage 100 km from open water under the Amery Ice Shelf, Antarctica. Paleoceanography 2007; 22: PA204.
Riedlecker EI, Ashton GV, Ruiz GM. Geometric morphometric analysis discriminates native and non-native species of Caprellidae in western North America. Journal of the Marine Biological Association of the United Kingdom 2009; 89: 535 42. 10.1017/s0025315408002452
Rogers AD. Evolution and biodiversity of Antarctic organisms: a molecular perspective. Philosophical Transactions of the Royal Society of London, Series B: Biological Sciences 2007; 362: 2191 214. 10.1098/rstb.2006.1948
Rohlf FJ, Slice D. Extensions of the Procrustes method for the optimal superimposition of landmarks. Systematic Zoology 1990; 39: 40 59. 10.2307/2992207
Ruane S. Using geometric morphometrics for integrative taxonomy: an examination of head shapes of milksnakes (genus Lampropeltis). Zoological Journal of the Linnean Society 2015; 174: 394 413. 10.1111/zoj.12245
Ruiz MB, Taverna A, Servetto N et al. Hidden diversity in Antarctica: molecular and morphological evidence of two different species within one of the most conspicuous ascidian species. Ecology and Evolution 2020; 10: 8127 43. 10.1002/ece3.6504
Sáez AG, Lozano E. Body doubles. Nature 2005; 433: 111. 10.1038/433111a
Saucède T, Eléaume M, Jossart Q et al. Taxonomy 2.0: computer-aided identification tools to assist Antarctic biologists in the field and in the laboratory. Antarctic Science 2021; 33: 39 51. 10.1017/s0954102020000462
Schellenberg A. Die Gammariden der deutschen Südpolar-Expedition 1901 - 1903. Deutsche Sudpolar-Expedition 1901-1903 1926; 18: 235 414.
Schlager S. Morpho and Rvcg - shape analysis in R: R-packages for geometric morphometrics, shape analysis and surface manipulations. In: Zheng G, Li S, Székely G (eds), Statistical Shape and Deformation Analysis. Amsterdam: Elsevier, 2017, 217 56.
Schlick-Steiner BC, Steiner FM, Seifert B et al. Integrative taxonomy: a multisource approach to exploring biodiversity. Annual Review of Entomology 2010; 55: 421 38. 10.1146/annurev-ento-112408-085432
Sheather SJ, Jones MC. A reliable data-based bandwidth selection method for kernel density estimation. Journal of the Royal Statistical Society: Series B (Methodological) 1991; 53: 683 90.
Tamura K, Stecher G, Peterson D et al. MEGA6: molecular evolutionary genetics analysis version 6.0. Molecular Biology and Evolution 2013; 30: 2725 9. 10.1093/molbev/mst197
Thatje S. Effects of capability for dispersal on the evolution of diversity in Antarctic benthos. Integrative and Comparative Biology 2012; 52: 470 82. 10.1093/icb/ics105
Thatje S, Hillenbrand CD, Larter R. On the origin of Antarctic marine benthic community structure. Trends in Ecology & Evolution 2005; 20: 534 40. 10.1016/j.tree.2005.07.010
Thornhill DJ, Mahon AR, Norenburg JL et al. Open-ocean barriers to dispersal: a test case with the Antarctic Polar Front and the ribbon worm Parborlasia corrugatus (Nemertea: Lineidae). Molecular Ecology 2008; 17: 5104 17. 10.1111/j.1365-294X.2008.03970.x
Trathan PN, Agnew D. Climate change and the Antarctic marine ecosystem: an essay on management implications. Antarctic Science 2010; 22: 387 98. 10.1017/s0954102010000222
Turner J, Bindschadler R, Convey P, et al. Antarctic Climate Change and the Environment. Cambridge, UK: Scientific Committee on Antarctic Research Scott Polar Research Institute, 2009.
d'Udekem d'Acoz C, Verheye ML. Epimeria of the Southern Ocean with notes on their relatives (Crustacea, Amphipoda, Eusiroidea). European Journal of Taxonomy 2017; 359: 1 553.
d'Udekem d'Acoz C, Schön I, Robert H. The genus Charcotia Chevreux, 1906 in the Southern Ocean, with the description of a new species (Crustacea, Amphipoda, Lysianassoidea). Belgian Journal of Zoology 2018; 148: 31 82.
Vaidya G, Lohman DJ, Meier R. SequenceMatrix: concatenation software for the fast assembly of multi-gene datasets with character set and codon information. Cladistics 2011; 27: 171 80. 10.1111/j.1096-0031.2010.00329.x
Verheye ML, Backeljau T, d'Udekem d'Acoz C. Looking beneath the tip of the iceberg: diversification of the genus Epimeria on the Antarctic shelf (Crustacea, Amphipoda). Polar Biology 2016; 39: 925 45. 10.1007/s00300-016-1910-5
Verheye ML, D'Udekem D'Acoz C. Integrative taxonomy of giant crested Eusirus in the Southern Ocean, including the description of a new species (Crustacea: Amphipoda: Eusiridae). Zoological Journal of the Linnean Society 2021; 193: 31 77.
Walker AO. Preliminary descriptions of new species of Amphipoda from the 'Discovery' Antarctic Expedition, 1902-1904. Annals and Magazine of Natural History, (Ser. 7) 1906; 17: 452 8.
Walker AO. Crustacea. III. Amphipoda. National Antartic Expedition 1901 - 1904. Natural History 1907; 3: 1 39.
Watanabe A. How many landmarks are enough to characterize shape and size variation? PLoS One 2018; 13: e0198341. 10.1371/journal.pone.0198341
Watling L. Functional morphology of the amphipod mandible. Journal of Natural History 1993; 27: 837 49. 10.1080/00222939300770511
Watling L, Holman H. Additional acanthonotozomatid, paramphitoid, and stegocephalid Amphipoda from the Southern Ocean. Proceedings of the Biological Society of Washington 1981; 94: 181 227.
Watling L, Thurston MH. Antarctica as an evolutionary incubator: evidence from the cladistic biogeography of the amphipod family Iphimediidae. Geological Society, London, Special Publications 1989; 47: 297 313. 10.1144/gsl.sp.1989.047.01.22
Wiens JJ. What is speciation and how should we study it? The American Naturalist 2004; 163: 914 23. 10.1086/386552
Wiens JJ. Species' delimitation: new approaches for discovering diversity. Systematic Biology 2007; 56: 875 8. 10.1080/10635150701748506
Zapata F, Jiménez I. Species' delimitation: inferring gaps in morphology across geography. Systematic Biology 2012; 61: 179 94. 10.1093/sysbio/syr084
Zhang J, Kapli P, Pavlidis P et al. A general species' delimitation method with applications to phylogenetic placements. Bioinformatics 2013; 29: 2869 76. 10.1093/bioinformatics/btt499
Zwickl DJ. Genetic algorithm approaches for the phylogenetic analysis of large biological sequence datasets under the maximum likelihood criterion. D.Phil. Thesis, The University of Texas, 2006.
Witt JDS, Threloff DL, Hebert PDN. DNA barcoding reveals extraordinary cryptic diversity in an amphipod genus: implications for desert spring conservation. Molecular Ecology 2006; 15: 3073 3082. doi: 10.1111/j.1365-294X.2006.02999.x
Powell JR. Accounting for uncertainty in species delineation during the analysis of environmental DNA sequence data. Methods in Ecology and Evolution 2011; 3: 1 11. doi: 10.1111/j.2041-210X.2011.00122.x
Garcia Sanz M, Constant E, Goussard F et al. Imaging methodologies in natural sciences: The AST-RX Platform (Accès Scientifique à la Tomographie à Rayons X) of the Muséum national d'Histoire naturelle. Paris. UVX 2012 2013; 01001: 1 7. doi: 10.1051/uvx/201301001
Ren X, Huang L. Studies on Gammaridea and Caprellidea (Crustacea: Amphipoda) from the northwest waters off the Antarctic Peninsula. Studia Marina Sinica 1991; 32: 185 323.
Coleman CO. Two new amphipod species (Crustacea) Iphimediella ruffoi and Iphimediella dominici from the Antarctic Ocean. Boll. Mus. civ. St. nat. Verona 1996; 20: 117 133.
Lörz A. First records of Epimeriidae and Iphimediidae (Crustacea, Amphipoda) from Macquarie Ridge, with description of a new species and its juveniles. Zootaxa 2012; 3200: 49 60.
Bickford D, Lohman DJ, Sohdi NS et al. Cryptic species as a window on diversity and conservation. Trends in Ecology and Evolution 2007; 22: 148 155.
