{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,7,30]],"date-time":"2026-07-30T09:15:27Z","timestamp":1785402927511,"version":"3.56.0"},"reference-count":31,"publisher":"MDPI AG","issue":"15","license":[{"start":{"date-parts":[[2026,7,30]],"date-time":"2026-07-30T00:00:00Z","timestamp":1785369600000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"Guangxi Natural Science Foundation of China","award":["2026GXNSFBA00640155"],"award-info":[{"award-number":["2026GXNSFBA00640155"]}]},{"name":"Guangxi Natural Science Foundation of China","award":["2026GXNSFAA00641116"],"award-info":[{"award-number":["2026GXNSFAA00641116"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Biology"],"abstract":"<jats:p>Inverted swimming behavior has been documented in marine arthropods from the Cambrian to modern oceans. It was previously theorized that this behavior contributed to bringing the center of gravity to a lower position, thereby enhancing balance and stability, and preventing clogging of the mouth in deposit and suspension feeders. In this study, by using the computational fluid dynamics analysis method and wave impact experiments, we evaluate the hydrodynamics of inverted swimming behavior in the early Cambrian Ercaicunia multinodosa when it was at the water surface. The results show that when Ercaicunia multinodosa swam at the water surface, the inverted swimming was more stable than the normal posture regardless of the direction from which the waves came. Moreover, as the wave amplitude increased (within the tested and validated range of 0.33 to 1.0 times the body height), the rate at which the flipping occurred in the normal posture was accelerated and then remained stable in the inverted posture. Finally, we used a stereolithography apparatus to create a physical model of Ercaicunia multinodosa and performed wave impact experiments to verify the research results. Our findings support the hypothesis that the inverted swimming behavior of Ercaicunia multinodosa helps increase balance and stability.<\/jats:p>","DOI":"10.3390\/biology15151252","type":"journal-article","created":{"date-parts":[[2026,7,30]],"date-time":"2026-07-30T08:09:42Z","timestamp":1785398982000},"page":"1252","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":0,"title":["Computational Fluid Dynamics to Investigate the Possible Behavior of Ercaicunia multinodosa While Swimming Inverted on the Water Surface"],"prefix":"10.3390","volume":"15","author":[{"ORCID":"https:\/\/orcid.org\/0000-0003-2844-3578","authenticated-orcid":false,"given":"Yuhan","family":"Li","sequence":"first","affiliation":[{"name":"School of Mechanical and Electrical Engineering, Guilin University of Electronic Technology, Guilin 541004, China"},{"name":"Postdoctoral Research Station in Information and Communication Engineering, Guilin University of Electronic Technology, Guilin 541004, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Zhizhe","family":"Yang","sequence":"additional","affiliation":[{"name":"School of Mechanical and Electrical Engineering, Guilin University of Electronic Technology, Guilin 541004, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-7814-0922","authenticated-orcid":false,"given":"Zupeng","family":"Zhou","sequence":"additional","affiliation":[{"name":"School of Mechanical and Electrical Engineering, Guilin University of Electronic Technology, Guilin 541004, China"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2026,7,30]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"101","DOI":"10.1038\/s41586-020-2883-7","article-title":"An early Cambrian euarthropod with radiodont-like raptorial appendages","volume":"588","author":"Zeng","year":"2020","journal-title":"Nature"},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"4006","DOI":"10.1016\/j.cub.2023.08.022","article-title":"The early Cambrian Kylinxia zhangi and evolution of the arthropod head","volume":"33","author":"Liu","year":"2023","journal-title":"Curr. Biol."},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"468","DOI":"10.1038\/nature11874","article-title":"Specialized appendages in fuxianhuiids and the head organization of early euarthropods","volume":"494","author":"Yang","year":"2013","journal-title":"Nature"},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"2023335","DOI":"10.1098\/rspb.2023.0335","article-title":"Three-dimensional morphology of the biramous appendages in Isoxys from the early Cambrian of South China, and its implications for early euarthropod evolution","volume":"290","author":"Zhang","year":"2023","journal-title":"Proc. R. Soc. B"},{"key":"ref_5","first-page":"476","article-title":"Application of the Micro-CT technique in the studies of arthropods from the Chengjiang Biota: A case of Miszhuia longicaudata","volume":"56","author":"Zhao","year":"2017","journal-title":"Acta Palaeontol. Sin."},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"4699","DOI":"10.1098\/rspb.2012.1958","article-title":"Cambrian bivalved arthropod reveals origin of arthrodization","volume":"279","author":"Legg","year":"2012","journal-title":"Proc. R. Soc. B"},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"526","DOI":"10.1038\/nature09704","article-title":"An armoured Cambrian lobopodian from China with arthropod-like appendages","volume":"470","author":"Liu","year":"2011","journal-title":"Nature"},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"1429","DOI":"10.1038\/srep01429","article-title":"Discovery of some 400 million years-old sensory structures in the ompound eyes of trilobites","volume":"3","author":"Schoenemann","year":"2013","journal-title":"Sci. Rep."},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"R1420","DOI":"10.1016\/j.cub.2021.10.003","article-title":"A \u2018hermit\u2019 shell-dwelling lifestyle in a Cambrian priapulan worm","volume":"31","author":"Yang","year":"2021","journal-title":"Curr. Biol."},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"597","DOI":"10.1111\/pala.12562","article-title":"Computational fluid dynamics confirms drag reduction associated with trilobite queuing behaviour","volume":"64","author":"Song","year":"2021","journal-title":"Palaeontology"},{"key":"ref_11","doi-asserted-by":"crossref","unstructured":"Benton, M.J. (2010). Studying function and behavior in the fossil record. PLoS Biol., 8.","DOI":"10.1371\/journal.pbio.1000321"},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"232","DOI":"10.1038\/138232a0","article-title":"Body orientation of the lower crustacea (Branchiopoda)","volume":"138","author":"Lochhead","year":"1936","journal-title":"Nature"},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"948","DOI":"10.1038\/137948a0","article-title":"Orientation of Chirocephalus and Daphnia","volume":"137","author":"Foxon","year":"1936","journal-title":"Nature"},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"241","DOI":"10.1038\/1402741a0","article-title":"Body Orientation in Crustacea","volume":"140","author":"Lowndes","year":"1937","journal-title":"Nature"},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"377","DOI":"10.1111\/j.1095-8312.2006.00623.x","article-title":"The brine shrimp\u2019s tale: A topsy turvy evolutionary fable","volume":"88","author":"Fryer","year":"2006","journal-title":"Biol. J. Linn. Soc."},{"key":"ref_16","first-page":"439","article-title":"The morphology, mode of life, and affinities of Canadaspis perfecta (Crustacea: Phyllocarida), middle Cambrian, Burgess Shale, British Columbia","volume":"281","author":"Briggs","year":"1978","journal-title":"Philos. Trans. R. Soc. B"},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"191350","DOI":"10.1098\/rsos.191350","article-title":"A possible case of inverted lifestyle in a new bivalved arthropod from the Burgess Shale","volume":"6","author":"Caron","year":"2019","journal-title":"R. Soc. Open Sci."},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"537","DOI":"10.11646\/zootaxa.4150.5.2","article-title":"Potamotrygon rex, a new species of Neotropical freshwater stingray (Chondrichthyes: Potamotrygonidae) from the middle and upper rio Tocantins, Brazil, closely allied to Potamotrygon henlei (Castelnau, 1855)","volume":"4150","author":"Carvalho","year":"2016","journal-title":"Zootaxa"},{"key":"ref_19","first-page":"276","article-title":"Observations on the swimming, righting, and burrowing movements of young horseshoe crabs, Limulus polyphemus","volume":"70","author":"Vosatka","year":"1970","journal-title":"Ohio J. Sci."},{"key":"ref_20","first-page":"221","article-title":"Evolution and adaptive radiation in the Chydoridae (Crustacea: Cladocera): A study in comparative functional morphology and ecology","volume":"254","author":"Fryer","year":"1968","journal-title":"Philos. Trans. R. Soc. B"},{"key":"ref_21","first-page":"27","article-title":"Studies on the functional morphology and biology of the Notostraca (Crustacea: Branchiopoda)","volume":"321","author":"Fryer","year":"1988","journal-title":"Philos. Trans. R. Soc. B"},{"key":"ref_22","doi-asserted-by":"crossref","first-page":"385","DOI":"10.1016\/j.palwor.2022.09.005","article-title":"Hydrodynamics and sliding posture analysis of the Cambrian arthropod Ercaicunia multinodosa","volume":"32","author":"Li","year":"2023","journal-title":"Palaeoworld"},{"key":"ref_23","doi-asserted-by":"crossref","first-page":"171","DOI":"10.1016\/j.cub.2018.11.060","article-title":"Three-dimensionally preserved appendages in an early Cambrian stem-group pancrustacean","volume":"29","author":"Zhai","year":"2019","journal-title":"Curr. Biol."},{"key":"ref_24","unstructured":"Luo, H.L., Hu, S.X., Chen, L.Z., Zhang, S.S., and Tao, Y.H. (1999). Early Cambrian Chengjiang Fauna from Kunming Region, China, Yunnan Science and Technology Press. (In Chinese)."},{"key":"ref_25","doi-asserted-by":"crossref","unstructured":"Hou, X.G., Siveter, D.J., Aldridge, R.J., Cong, P.Y., Gabbott, S.E., Ma, X.Y., Purnell, M.A., and Williams, M. (2017). The Cambrian Fossils of Chengjiang, China: The Flowering of Early Animal Life, John Wiley & Sons. [2nd ed.].","DOI":"10.1002\/9781118896372"},{"key":"ref_26","unstructured":"Anderson, H.T. (1969). Hydrodynamics of swimming and wave-riding dolphins. The Biology of Marine Mammals, Academic Press."},{"key":"ref_27","doi-asserted-by":"crossref","first-page":"763","DOI":"10.1242\/jeb.53.3.763","article-title":"The metabolic cost of swimming in ducks","volume":"53","author":"Prange","year":"1970","journal-title":"J. Exp. Biol."},{"key":"ref_28","doi-asserted-by":"crossref","first-page":"2979","DOI":"10.1242\/jeb.006437","article-title":"Swimming in the upside down catfish Synodontis nigriventris: It matters which way is up","volume":"210","author":"Blake","year":"2007","journal-title":"J. Exp. Biol."},{"key":"ref_29","doi-asserted-by":"crossref","first-page":"782","DOI":"10.1119\/1.13550","article-title":"Elementary derivation of the wake pattern of a boat","volume":"52","author":"Crawford","year":"1984","journal-title":"Am. J. Phys."},{"key":"ref_30","first-page":"541","article-title":"The arthropod Odaraia alata walcott, middle Cambrian, burgess shale, British Columbia","volume":"291","author":"Briggs","year":"1981","journal-title":"Philos. Trans. R. Soc. B"},{"key":"ref_31","first-page":"329","article-title":"Rare arthropods from the Burgess Shale, Middle Cambrian, British Columbia","volume":"292","author":"Whittington","year":"1981","journal-title":"Philos. Trans. R. Soc. B"}],"container-title":["Biology"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/2079-7737\/15\/15\/1252\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2026,7,30]],"date-time":"2026-07-30T08:42:44Z","timestamp":1785400964000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/2079-7737\/15\/15\/1252"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2026,7,30]]},"references-count":31,"journal-issue":{"issue":"15","published-online":{"date-parts":[[2026,8]]}},"alternative-id":["biology15151252"],"URL":"https:\/\/doi.org\/10.3390\/biology15151252","relation":{},"ISSN":["2079-7737"],"issn-type":[{"value":"2079-7737","type":"electronic"}],"subject":[],"published":{"date-parts":[[2026,7,30]]}}}