Giant Mesozoic Coelacanths (Osteichthyes, Actinistia) Reveal High Body Size Disparity Decoupled From Taxic Diversity

Giant Mesozoic Coelacanths (Osteichthyes, Actinistia) Reveal High Body Size Disparity Decoupled From Taxic Diversity | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Research Article Giant Mesozoic Coelacanths (Osteichthyes, Actinistia) Reveal High Body Size Disparity Decoupled From Taxic Diversity Lionel Cavin, André Piuz, Christophe Ferrante, Guillaume Guinot This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-245480/v1 This work is licensed under a CC BY 4.0 License Status: Under Review Version 1 posted 8 You are reading this latest preprint version Abstract The positive correlation between speciation rates and morphological evolution expressed by body size is a macroevolutionary trait of vertebrates. Although taxic diversification and morphological evolution are slow in coelacanths, their fossil record indicates that large and small species coexisted, which calls into question the link between morphological and body size disparities. Here, we describe and reassess fossils of giant coelacanths. Two genera reached up to 5 meters long, placing them among the ten largest bony fish that ever lived. The disparity in body size adjusted to taxic diversity is much greater in coelacanths than in ray-finned fishes, and is decoupled from a high rate of speciation or a high rate of morphological evolution. Genomic and physiological characteristics of the extant Latimeria may reflect how the extinct relatives grew to such a large size. These characteristics highlight new evolutionary traits specific to these “living fossils”. Geology morphological evolution taxic diversification Genomic and physiological characteristics Figures Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 Full-Text Due to technical limitations, full-text HTML conversion of this manuscript could not be completed. However, the manuscript can be downloaded and accessed as a PDF. Additional Declarations No competing interests reported. Supplementary Files CavinetalcoelacanthsSII.pdf CavinetalSIbodysize.xlsx Media1.wmv Cite Share Download PDF Status: Under Review Version 1 posted Editorial decision: Major revision 16 Apr, 2021 Reviews received at journal 06 Mar, 2021 Reviewers agreed at journal 24 Feb, 2021 Reviewers invited by journal 23 Feb, 2021 Editor assigned by journal 23 Feb, 2021 Editor invited by journal 18 Feb, 2021 Submission checks completed at journal 18 Feb, 2021 First submitted to journal 16 Feb, 2021 You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. We do this by developing innovative software and high quality services for the global research community. Our growing team is made up of researchers and industry professionals working together to solve the most critical problems facing scientific publishing. Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-245480","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":12561630,"identity":"1b7d39af-3d85-4253-9e88-af7ea727539f","order_by":0,"name":"Lionel Cavin","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAABAElEQVRIiWNgGAWjYBACPmYQWQAiGBsYPjBIyPBBZRJwaWEDazGAaGGcwSDBw0ZQCwNcCwMDMw8DAxFa2JmPPfhgwCDPPyO57bFtmwUPG3sD84sPDHZ5uB3Glm44w4DBcMaNxHbj3Dagw3gOsFnOYEguxq2Fx0yaxwDojDMH26RzzgC1SOR/M+ZhOJDYgE/LH6AWeZAWC5AW+Qdsxn8IaQF6P8HgeGObNEMFyBYG5scMeLWwpUn2GEgYbgRqkewBaeFJYGPsMUjGqYWf//AxiR8VNvJyh9mfSfwwqJPjZz/A/OFHhR1OLVAggWq1BCymiAbMH0jUMApGwSgYBcMbAACDX0Kfkyda7QAAAABJRU5ErkJggg==","orcid":"","institution":"Natural History Museum of Geneva","correspondingAuthor":true,"submittingAuthor":false,"prefix":"","firstName":"Lionel","middleName":"","lastName":"Cavin","suffix":""},{"id":12561631,"identity":"adb63a32-357e-4ab8-8da1-dc3eac201879","order_by":1,"name":"André Piuz","email":"","orcid":"","institution":"Natural History Museum of Geneva","correspondingAuthor":false,"submittingAuthor":false,"prefix":"","firstName":"André","middleName":"","lastName":"Piuz","suffix":""},{"id":12561632,"identity":"6dd8e803-efe7-4b30-ac5b-9288dc1c5705","order_by":2,"name":"Christophe Ferrante","email":"","orcid":"","institution":"Natural History Museum of Geneva","correspondingAuthor":false,"submittingAuthor":false,"prefix":"","firstName":"Christophe","middleName":"","lastName":"Ferrante","suffix":""},{"id":12561633,"identity":"7bfeee4f-c062-46be-872e-d1d8347f26b4","order_by":3,"name":"Guillaume Guinot","email":"","orcid":"","institution":"Institut des Sciences de l'Evolution de Montpellier","correspondingAuthor":false,"submittingAuthor":false,"prefix":"","firstName":"Guillaume","middleName":"","lastName":"Guinot","suffix":""}],"badges":[],"createdAt":"2021-02-16 17:14:05","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-245480/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-245480/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":6519605,"identity":"f9ce4ee1-cb63-483e-bd04-0144a61fc3e2","added_by":"auto","created_at":"2021-03-02 15:01:38","extension":"jpg","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":99436,"visible":true,"origin":"","legend":"Foraminifera found in the matrix containing the fragment of the coelacanth skull (MHNG GEPI V5778). 1-4, Epistomina ex. gr. mosquensis Uhlig 1883, umbilical, apertural, carinal and spiral views; 5-8, Epistomina ex. gr. uhligi Mjatliuk 1953, spiral, apertural and umbilical views; 9-11, Lenticulina muensteri (Roemer 1839), apertural and lateral views; 12-13, Lenticulina quenstedti (Gümbel 1862), apertural and lateral views; 14, Lenticulina subalata (Reuss 1854), apertural and lateral views; 15, Planularia beierana (Gümbel 1862), lateral and apertural views.","description":"","filename":"Fig1.jpg","url":"https://assets-eu.researchsquare.com/files/rs-245480/v1/fd0251c9ce1a3aa9d848eba3.jpg"},{"id":6519311,"identity":"99ca6285-5ed7-46cf-bc10-a898d292a303","added_by":"auto","created_at":"2021-03-02 14:58:38","extension":"jpg","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":83815,"visible":true,"origin":"","legend":"MHNG GEPI V5778. Trachymetopon sp. Basisphenoid with fragments of the posterior parietals and parasphenoid. Dorsal (a), dorsoposterior (b) and left lateral views. d, detail of exits of the nerve in anterolaterodorsal view (corresponding approximately to the frame in c); e, position of the fossil in a schematic reconstruction of the braincase of a mawsoniid coelacanth (modified from Maisey, 1986). Abbreviations: d.s, dorsum sellae; f.s.o.sc, foramen for the supraorbital sensory canal; f.s.opth, foramen for the superficial ophthalmic nerve; f.III, foramen for the oculomotor nerve; f.IV, foramen for the trochlear nerve (IV); ant. pr, antotic process; Par, parasphenoid; pr.con, processus conectens; pPa, posterior parietal; sph.c, sphenoid condyle; spt.fos, suprapterygoid fossa; v.pr.pPa, ventral process of the parietal posterior.","description":"","filename":"Fig2.jpg","url":"https://assets-eu.researchsquare.com/files/rs-245480/v1/2b5bb2ccc6432daf2192691b.jpg"},{"id":6519316,"identity":"f42b29eb-c2bf-4a3e-90a1-7a314ac387ac","added_by":"auto","created_at":"2021-03-02 14:58:38","extension":"jpg","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":64570,"visible":true,"origin":"","legend":"Basisphenoids of embryos or newborns of Trachymetopon sp. from Callovian beds from the Vaches Noires. a, Comparison of the giant form (MHNG GEPI V5778) with basisphenoids of embryos or newborns (MPV 2020.1.13); b, details of the parasphenoids of the embryos or newborns (MPV 2020.1.13a and MPV 2020.1.13a) in ventral (left) and dorsal (right) views. Abbreviations: b.h.c, buccohypophysal canal; d.s, dorsum sellae; pit. fos, pituitary fossa; sph.c, sphenoid condyle.","description":"","filename":"Fig3.jpg","url":"https://assets-eu.researchsquare.com/files/rs-245480/v1/9372425e3db87d31d6df3fa7.jpg"},{"id":6519315,"identity":"2be9f616-84cb-46b6-bb0a-90952fed1b03","added_by":"auto","created_at":"2021-03-02 14:58:38","extension":"jpg","order_by":4,"title":"Figure 4","display":"","copyAsset":false,"role":"figure","size":99043,"visible":true,"origin":"","legend":"Trachymetopon (“Macropoma”) substriolatum (holotype, SMC J27415) from the Kimmeridgian of Cottenham, Cambridgeshire. Photograph (1) and semi-interpretative drawings in dorsal (a), ventral (b), anterior (c), left lateral (d) and right lateral (e) views. Scale bars = 50 mm. Abbreviations: Ang, angular; Bsph, basisphenoid; Ext, extrascapular; Gu, gular; L.j, lachrymojugal; Op, opercle; Par, parasphenoid; p.Co, principal coronoid; Pop, postparietal; Pp, postparietal; Po, postorbital; Q, quadrate; Sc, scale; So, supraorbital; Sq, squamosal; Stt, supratemporal.","description":"","filename":"Fig4.jpg","url":"https://assets-eu.researchsquare.com/files/rs-245480/v1/775366f571c15036021dfc48.jpg"},{"id":6519608,"identity":"56424af0-ca80-4a27-bf48-6356fbaf5aa0","added_by":"auto","created_at":"2021-03-02 15:01:38","extension":"jpg","order_by":5,"title":"Figure 5","display":"","copyAsset":false,"role":"figure","size":120926,"visible":true,"origin":"","legend":"Fragmentary elements from the giant specimens of the Jurassic Trachymetopon and the Cretaceous Mawsonia. Human silhouettes corresponds to 1.8 m.","description":"","filename":"Fig5.jpg","url":"https://assets-eu.researchsquare.com/files/rs-245480/v1/3818743e71e67c0affb51d39.jpg"},{"id":6519606,"identity":"661746cf-d234-4e9e-8850-19da24210aa7","added_by":"auto","created_at":"2021-03-02 15:01:38","extension":"jpg","order_by":6,"title":"Figure 6","display":"","copyAsset":false,"role":"figure","size":54651,"visible":true,"origin":"","legend":"a, range-through genus richness (histograms) and disparity expressed by the coefficient of variation (dots and lines); b, per genus coefficient of variation, which is the coefficient of variation standardized by taxic diversity. Orange, Actinopterygii; blue, Actinistia.","description":"","filename":"Fig6.jpg","url":"https://assets-eu.researchsquare.com/files/rs-245480/v1/762efff068c5b7e4156d3cd1.jpg"},{"id":13598717,"identity":"1f165f49-9902-4c8b-bbf0-da14d906619b","added_by":"auto","created_at":"2021-09-17 05:36:48","extension":"pdf","order_by":1,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":1871755,"visible":true,"origin":"","legend":"","description":"","filename":"Cavinetalcoelacanths.pdf","url":"https://assets-eu.researchsquare.com/files/rs-245480/v1_covered.pdf"},{"id":6520187,"identity":"07bccb0c-14ee-47c1-8481-66a0319953d4","added_by":"auto","created_at":"2021-03-02 15:07:42","extension":"pdf","order_by":1,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":1790249,"visible":true,"origin":"","legend":"","description":"","filename":"Cavinetalcoelacanths.pdf","url":"https://assets-eu.researchsquare.com/files/rs-245480/v1_stamped.pdf"},{"id":6519607,"identity":"83a8bb5c-7d80-422a-a1b0-2f7a911e5322","added_by":"auto","created_at":"2021-03-02 15:01:38","extension":"pdf","order_by":1,"title":"","display":"","copyAsset":false,"role":"supplement","size":913284,"visible":true,"origin":"","legend":"","description":"","filename":"CavinetalcoelacanthsSII.pdf","url":"https://assets-eu.researchsquare.com/files/rs-245480/v1/37d0ea26bf875fbd32aafc71.pdf"},{"id":6519313,"identity":"606c3f00-2029-490e-b53b-ed13ba5f6dc4","added_by":"auto","created_at":"2021-03-02 14:58:38","extension":"xlsx","order_by":2,"title":"","display":"","copyAsset":false,"role":"supplement","size":187056,"visible":true,"origin":"","legend":"","description":"","filename":"CavinetalSIbodysize.xlsx","url":"https://assets-eu.researchsquare.com/files/rs-245480/v1/e5a0e048233b130d5fca0dfa.xlsx"},{"id":6519896,"identity":"142a5f9d-38c0-4c65-8baf-2dc44e6f047d","added_by":"auto","created_at":"2021-03-02 15:04:38","extension":"wmv","order_by":3,"title":"","display":"","copyAsset":false,"role":"supplement","size":26637940,"visible":true,"origin":"","legend":"","description":"","filename":"Media1.wmv","url":"https://assets-eu.researchsquare.com/files/rs-245480/v1/a82a810214a04c46f06be0c6.wmv"}],"financialInterests":"No competing interests reported.","formattedTitle":"\u003cp\u003eGiant Mesozoic Coelacanths (Osteichthyes, Actinistia) Reveal High Body Size Disparity Decoupled From Taxic Diversity\u003c/p\u003e","fulltext":[{"header":"Full-Text","content":"\n\u003cp\u003eDue to technical limitations, full-text HTML conversion of this manuscript could not be completed. However, the manuscript can be downloaded and accessed as a PDF.\u003c/p\u003e\n"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":false,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":false,"highlight":"","institution":"","isAcceptedByJournal":true,"isAuthorSuppliedPdf":true,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"scientific-reports","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"scirep","sideBox":"Learn more about [Scientific Reports](http://www.nature.com/srep/)","snPcode":"","submissionUrl":"","title":"Scientific Reports","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"stoa","reportingPortfolio":"Scientific Reports","inReviewEnabled":true,"inReviewRevisionsEnabled":true},"keywords":"morphological evolution, taxic diversification, Genomic and physiological characteristics","lastPublishedDoi":"10.21203/rs.3.rs-245480/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-245480/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003eThe positive correlation between speciation rates and morphological evolution expressed by body size is a macroevolutionary trait of vertebrates. Although taxic diversification and morphological evolution are slow in coelacanths, their fossil record indicates that large and small species coexisted, which calls into question the link between morphological and body size disparities. Here, we describe and reassess fossils of giant coelacanths. Two genera reached up to 5 meters long, placing them among the ten largest bony fish that ever lived. The disparity in body size adjusted to taxic diversity is much greater in coelacanths than in ray-finned fishes, and is decoupled from a high rate of speciation or a high rate of morphological evolution. Genomic and physiological characteristics of the extant Latimeria may reflect how the extinct relatives grew to such a large size. These characteristics highlight new evolutionary traits specific to these “living fossils”.\u003c/p\u003e","manuscriptTitle":"Giant Mesozoic Coelacanths (Osteichthyes, Actinistia) Reveal High Body Size Disparity Decoupled From Taxic Diversity","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2021-03-02 14:58:36","doi":"10.21203/rs.3.rs-245480/v1","editorialEvents":[{"type":"communityComments","content":0},{"type":"decision","content":"Major revision","date":"2021-04-16T13:35:59+00:00","index":"","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2021-03-06T18:23:22+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"af6a0d77-832b-444b-b574-b108ff849cb0","date":"2021-02-24T10:53:34+00:00","index":"hide","fulltext":""},{"type":"reviewersInvited","content":"","date":"2021-02-24T01:40:36+00:00","index":"","fulltext":""},{"type":"editorAssigned","content":"","date":"2021-02-24T01:36:23+00:00","index":"","fulltext":""},{"type":"editorInvited","content":"","date":"2021-02-18T17:28:57+00:00","index":"","fulltext":""},{"type":"checksComplete","content":"","date":"2021-02-18T13:46:45+00:00","index":"","fulltext":""},{"type":"submitted","content":"Scientific Reports","date":"2021-02-16T17:02:58+00:00","index":"","fulltext":""}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"scientific-reports","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"scirep","sideBox":"Learn more about [Scientific Reports](http://www.nature.com/srep/)","snPcode":"","submissionUrl":"","title":"Scientific Reports","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"stoa","reportingPortfolio":"Scientific Reports","inReviewEnabled":true,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"28da7b3d-9940-45aa-b125-129def085632","owner":[],"postedDate":"March 2nd, 2021","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"under-review","subjectAreas":[{"id":2706770,"name":"Geology"}],"tags":[],"updatedAt":"2021-05-17T05:14:03+00:00","versionOfRecord":[],"versionCreatedAt":"2021-03-02 14:58:36","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-245480","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-245480","identity":"rs-245480","version":["v1"]},"buildId":"-HB7Z8yhvgn0wM9Nzuekk","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}