A tough nut to crack: multiple indirect pieces of evidence show a temporally and spatially complex invasion process of genus Carnicus in Argentine Patagonia

A tough nut to crack: multiple indirect pieces of evidence show a temporally and spatially complex invasion process of genus Carnicus in Argentine Patagonia | 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 A tough nut to crack: multiple indirect pieces of evidence show a temporally and spatially complex invasion process of genus Carnicus in Argentine Patagonia Berenice Trovant, Irina Candela Silva, Ivanna Haydée Tomasco This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-7067188/v1 This work is licensed under a CC BY 4.0 License Status: Posted Version 1 posted You are reading this latest preprint version Abstract Marine invasive species pose serious threats to biodiversity and exert significant ecological and economic pressures. The genus Carcinus ranks among the most widespread marine invaders, with established populations on all continents except Antarctica. As a generalist and active predator, it jeopardizes native coastal ecosystems and the livelihoods of fishing communities. Despite its broad global distribution, invasion dynamics in some regions—such as the Southwestern Atlantic (SWA)—remain poorly understood. We aim to understand the dynamics of the Carnicus invasion in the SWA through analyzing morphological traits and mitochondrial DNA variation along the Patagonian coast of Argentina. Our results challenge the prevailing hypothesis of a single introduction event of C. maenas followed by a northward expansion. Instead, we detected an uneven geographical distribution of C. maenas and C. aestuarii, alongside higher genetic diversity in northern populations. Assuming no introgression between species, our findings support a more complex scenario involving multiple, spatially and temporally independent introduction events. These results call for a revision of existing invasion models for Carcinus in this region and underscore the need for further research into the origins of these introductions, the potential for hybridization, and the ecological factors shaping current distribution patterns. cryptic introduction invasive species COI Southwestern Atlantic Ocean Figures Figure 1 Figure 2 Figure 3 Full Text Supplementary Files TablesTrovantetal.docx OnlineResource1.docx OnlineResource2.docx OnlineResource3.docx OnlineResource4.docx Cite Share Download PDF Status: Posted Version 1 posted 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. 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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-7067188","acceptedTermsAndConditions":true,"allowDirectSubmit":true,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":497228671,"identity":"2263d212-c07f-4c6b-8aed-b2a9ef61a13d","order_by":0,"name":"Berenice Trovant","email":"","orcid":"","institution":"Universidad Nacional de la Patagonia San Juan Bosco","correspondingAuthor":false,"prefix":"","firstName":"Berenice","middleName":"","lastName":"Trovant","suffix":""},{"id":497228672,"identity":"b017ea54-45d2-465b-9896-a11597cc9408","order_by":1,"name":"Irina Candela Silva","email":"","orcid":"","institution":"Universidad Nacional de la Patagonia San Juan Bosco","correspondingAuthor":false,"prefix":"","firstName":"Irina","middleName":"Candela","lastName":"Silva","suffix":""},{"id":497228673,"identity":"07be2499-6286-4000-85b5-3b6b26a275d2","order_by":2,"name":"Ivanna Haydée Tomasco","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAAzklEQVRIiWNgGAWjYBACNghlw8/ADGYwE60lTbKBaC1QcFiygYFYLXwSyc8eF9Scl+BvZz72gKHCOrFBIscAv8Mk0syNZxy7LSFxmC3dgOFMOhFaeA6YSfOw3a4zYOYxk2BsO0yMluPfpHn+nZMwYOb/JsH4jxgt7D1m0rxtB4BaeNgkGBuI01ImzduXDPKLmUTCsXTjNp5nBXi1yDezb5Pm+WYnwd9/+JnEhxpr2X725A14taCCBJC9DBz4HYYNsD8gWcsoGAWjYBQMawAAlAo4LaDD6VMAAAAASUVORK5CYII=","orcid":"https://orcid.org/0000-0002-8288-8618","institution":"Universidad de la Republica Uruguay Facultad de Ciencias","correspondingAuthor":true,"prefix":"","firstName":"Ivanna","middleName":"Haydée","lastName":"Tomasco","suffix":""}],"badges":[],"createdAt":"2025-07-07 15:51:21","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-7067188/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-7067188/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":89315841,"identity":"69070c28-9324-4047-8c98-43dc5330eb86","added_by":"auto","created_at":"2025-08-18 16:57:31","extension":"jpg","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":106161,"visible":true,"origin":"","legend":"\u003cp\u003eDynamics introduction hypothesis of \u003cem\u003eCarcinus spp.\u003c/em\u003e along the Argentine Patagonian coast. Sites 1–5 are sampling locations; black years indicate first species detection. Anchor symbols indicate international ports. Red arrows represent a hypothesis of a single southern introduction (Golfo San Jorge) followed by a northward expansion, with estimated dispersal rates in kilometers per year. Blue dashed arrows denote the hypothesis of multiple introduction events suggested through molecular analyses. 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