{"id":11805,"date":"2024-05-14T12:11:19","date_gmt":"2024-05-14T10:11:19","guid":{"rendered":"https:\/\/wp.unil.ch\/geoblog\/2024\/05\/un-doctorant-de-lunil-elucide-lorigine-des-scorpions-des-araignees-et-des-limules\/"},"modified":"2024-05-14T12:24:33","modified_gmt":"2024-05-14T10:24:33","slug":"discovery-of-the-first-ancestors-of-scorpions-spiders-and-horseshoe-crabs","status":"publish","type":"post","link":"https:\/\/wp.unil.ch\/geoblog\/en\/2024\/05\/discovery-of-the-first-ancestors-of-scorpions-spiders-and-horseshoe-crabs\/","title":{"rendered":"Discovery of the first ancestors of scorpions, spiders and horseshoe crabs"},"content":{"rendered":"\n<div class=\"wp-block-group has-background has-global-padding is-layout-constrained wp-block-group-is-layout-constrained\" style=\"background-color:#eeeeee\">\n<figure class=\"wp-block-image alignleft size-full is-resized is-style-rounded\"><a href=\"https:\/\/wp.unil.ch\/geoblog\/files\/2024\/05\/lustri.jpg\"><img alt=\"\" loading=\"lazy\" decoding=\"async\" width=\"800\" height=\"800\" src=\"https:\/\/wp.unil.ch\/geoblog\/files\/2024\/05\/lustri.jpg\" alt=\"\" class=\"wp-image-11792\" style=\"width:250px\" srcset=\"https:\/\/wp.unil.ch\/geoblog\/files\/2024\/05\/lustri.jpg 800w, https:\/\/wp.unil.ch\/geoblog\/files\/2024\/05\/lustri-300x300.jpg 300w, https:\/\/wp.unil.ch\/geoblog\/files\/2024\/05\/lustri-150x150.jpg 150w, https:\/\/wp.unil.ch\/geoblog\/files\/2024\/05\/lustri-768x768.jpg 768w\" sizes=\"auto, (max-width: 800px) 100vw, 800px\" \/><\/a><figcaption class=\"wp-element-caption\">Lorenzo Lustri, Institute of Earth Sciences<\/figcaption><\/figure>\n\n\n\n<p><strong><strong>Who were the earliest ancestors of scorpions, spiders and horseshoe crabs?<\/strong><\/strong><\/p>\n\n\n\n<p>A PhD student from the University of Lausanne (Switzerland), with the support of a CNRS researcher , has identified a fossil that fills the gap between modern species and those from the Cambrian period (505 million years ago), solving a long paleontological mystery.<\/p>\n\n\n\n<div style=\"height:1px\" aria-hidden=\"true\" class=\"wp-block-spacer\"><\/div>\n<\/div>\n\n\n\n<figure class=\"wp-block-embed is-type-video is-provider-youtube wp-block-embed-youtube wp-embed-aspect-16-9 wp-has-aspect-ratio\"><div class=\"wp-block-embed__wrapper\">\n<iframe loading=\"lazy\" title=\"Setapedites abundantis Lustri, Gueriau &amp; Daley, 2024\" width=\"500\" height=\"281\" src=\"https:\/\/www.youtube.com\/embed\/k6u6YF7Wvsk?feature=oembed\" frameborder=\"0\" allow=\"accelerometer; autoplay; clipboard-write; encrypted-media; gyroscope; picture-in-picture; web-share\" referrerpolicy=\"strict-origin-when-cross-origin\" allowfullscreen><\/iframe>\n<\/div><\/figure>\n\n\n\n<p>Modern scorpions, spiders and horseshoe crabs belong to the vast lineage of arthropods, which appeared on earth nearly 540 million years ago. More precisely, they belong to a subphylum that includes organisms equipped with pincers used notably for biting, grasping prey, or injecting venom &#8211; the chelicerae, hence their name chelicerates. But what are the ancestors of this very specific group?<\/p>\n\n\n\n<p>This question has puzzled paleontologists ever since the study of ancient fossils began. It was impossible to identify with certainty any forms among early arthropods that shared enough similarities with modern species to be considered ancestors. The mystery was further compounded by the lack of fossils available for the key period between -505 and -430 million years ago, which would have facilitated genealogical investigation.<\/p>\n\n\n\n<figure class=\"wp-block-image alignleft size-large is-resized\"><a href=\"https:\/\/wp.unil.ch\/geoblog\/files\/2024\/05\/setapedites-abundantis.jpg\"><img alt=\"\" loading=\"lazy\" decoding=\"async\" width=\"1024\" height=\"683\" src=\"https:\/\/wp.unil.ch\/geoblog\/files\/2024\/05\/setapedites-abundantis-1024x683.jpg\" alt=\"\" class=\"wp-image-11796\" style=\"width:735px;height:auto\" srcset=\"https:\/\/wp.unil.ch\/geoblog\/files\/2024\/05\/setapedites-abundantis-1024x683.jpg 1024w, https:\/\/wp.unil.ch\/geoblog\/files\/2024\/05\/setapedites-abundantis-300x200.jpg 300w, https:\/\/wp.unil.ch\/geoblog\/files\/2024\/05\/setapedites-abundantis-768x512.jpg 768w, https:\/\/wp.unil.ch\/geoblog\/files\/2024\/05\/setapedites-abundantis.jpg 1200w\" sizes=\"auto, (max-width: 1024px) 100vw, 1024px\" \/><\/a><figcaption class=\"wp-element-caption\">One of the Setapedites abundantis fossils that have been used to trace the origins of spiders, scorpions and horseshoe crabs. \u00a9 UNIL<\/figcaption><\/figure>\n\n\n\n<div style=\"height:1px\" aria-hidden=\"true\" class=\"wp-block-spacer\"><\/div>\n\n\n\n<p>Lorenzo Lustri, then a PhD student at the University of Lausanne (UNIL)&#8217;s Faculty of Geosciences and Environment, provided the missing piece of the puzzle. Together with his supervisors, he studied a hundred fossils dating back 478 million years from the Fezouata Shale of Morocco and identified the candidate that links modern organisms to those of the Cambrian (505 million years ago). The study was published in Nature Communications.<\/p>\n\n\n\n<p>Fossils from the Fezouata Shale were discovered in the early 2000s and have undergone extensive analysis. However, the fossil illustrated in the publication, one of the most abundant in the deposit, had never been described before. Measuring between 5 and 10 millimeters in size, it has been named Setapedites abundantis. This animal makes it possible, for the first time, to trace the entire lineage of chelicerates, from the appearance of the earliest arthropods to modern spiders, scorpions and horseshoe crabs.<\/p>\n\n\n\n<p>\u201cInitially, we only intended to describe and name this fossil. We had absolutely no idea that it would hold so many secrets,\u201d confides Lorenzo Lustri, the paper&#8217;s first author, who defended his PhD in March 2023. \u201cIt was therefore an exhilarating surprise to realize, after careful observations and analysis, that it also filled an important gap in the evolutionary tree of life.\u201d<\/p>\n\n\n\n<p>Still, the fossil has yet to reveal all its secrets. In fact, some of its anatomical features allow for a deeper understanding of the early evolution of the chelicerate group, and perhaps even link to this group other fossil forms whose affinities remain highly debated.<\/p>\n\n\n\n<p>A temporary exhibition on the Fezouata biota, in collaboration with UNIL, will soon be held at the Palais de Rumine in Lausanne, Switzerland.<\/p>\n\n\n\n<div class=\"wp-block-columns is-layout-flex wp-container-core-columns-is-layout-28f84493 wp-block-columns-is-layout-flex\">\n<div class=\"wp-block-column is-layout-flow wp-block-column-is-layout-flow\" style=\"flex-basis:70%\">\n<h5 class=\"wp-block-heading\"><strong>Source<\/strong><\/h5>\n\n\n\n<ul class=\"wp-block-list\">\n<li>L. Lustri, P. Gueriau, and A. C. Daley,&nbsp;<a href=\"https:\/\/www.nature.com\/articles\/s41467-024-48013-w\" target=\"_blank\" rel=\"noreferrer noopener\">Lower Ordovician synziphosurine reveals early euchelicerate diversity and evolution<\/a>,<em>&nbsp;Nature Communications<\/em>.<\/li>\n<\/ul>\n<\/div>\n\n\n\n<div class=\"wp-block-column is-layout-flow wp-block-column-is-layout-flow\" style=\"flex-basis:30%\"><\/div>\n<\/div>\n\n\n\n<div class=\"wp-block-group bordure has-global-padding is-layout-constrained wp-block-group-is-layout-constrained\">\n<h3 class=\"wp-block-heading\"><strong>Method<\/strong><\/h3>\n\n\n\n<figure class=\"wp-block-image alignright size-full\"><a href=\"https:\/\/wp.unil.ch\/geoblog\/files\/2023\/02\/limule.png\"><img alt=\"\" loading=\"lazy\" decoding=\"async\" width=\"227\" height=\"320\" src=\"https:\/\/wp.unil.ch\/geoblog\/files\/2023\/02\/limule.png\" alt=\"\" class=\"wp-image-9393\" srcset=\"https:\/\/wp.unil.ch\/geoblog\/files\/2023\/02\/limule.png 227w, https:\/\/wp.unil.ch\/geoblog\/files\/2023\/02\/limule-213x300.png 213w\" sizes=\"auto, (max-width: 227px) 100vw, 227px\" \/><\/a><figcaption class=\"wp-element-caption\">Reconstruction of Setapedites abundantis \u00a9Elissa Sorojsrisom<\/figcaption><\/figure>\n\n\n\n<p>To obtain these results, the scientists studied a hundred fossils and used an X-ray scanner to reconstruct their anatomy in detail and in 3D. They were then able to draw comparisons with numerous fossil chelicerates from other sites, as well as with their more ancient relatives. Finally, the importance of the Fezouata fossil became clear with the help of phylogenetic analyses, which mathematically reconstruct the family tree of different species based on the \u201ccoding\u201d of all their anatomical traits.\u00a0\u00a0<\/p>\n\n\n\n<div style=\"height:10px\" aria-hidden=\"true\" class=\"wp-block-spacer\"><\/div>\n<\/div>\n","protected":false},"excerpt":{"rendered":"<p>Who were the earliest ancestors of scorpions, spiders and horseshoe crabs? A PhD student from the University of Lausanne (Switzerland), with the support of a CNRS researcher , has identified a fossil that fills the gap between modern species and those from the Cambrian period (505 million years ago), solving a long paleontological mystery. Modern [&hellip;]<\/p>\n","protected":false},"author":1002548,"featured_media":11797,"comment_status":"open","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_seopress_robots_primary_cat":"","_seopress_titles_title":"","_seopress_titles_desc":"","_seopress_robots_index":"","footnotes":"","_links_to":"","_links_to_target":""},"categories":[67100,67041],"tags":[67187],"class_list":{"0":"post-11805","1":"post","2":"type-post","3":"status-publish","4":"format-standard","5":"has-post-thumbnail","7":"category-publishing","8":"category-research-at-work","9":"tag-lorenzo-lustri-en"},"_links":{"self":[{"href":"https:\/\/wp.unil.ch\/geoblog\/en\/wp-json\/wp\/v2\/posts\/11805","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/wp.unil.ch\/geoblog\/en\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/wp.unil.ch\/geoblog\/en\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/wp.unil.ch\/geoblog\/en\/wp-json\/wp\/v2\/users\/1002548"}],"replies":[{"embeddable":true,"href":"https:\/\/wp.unil.ch\/geoblog\/en\/wp-json\/wp\/v2\/comments?post=11805"}],"version-history":[{"count":2,"href":"https:\/\/wp.unil.ch\/geoblog\/en\/wp-json\/wp\/v2\/posts\/11805\/revisions"}],"predecessor-version":[{"id":11808,"href":"https:\/\/wp.unil.ch\/geoblog\/en\/wp-json\/wp\/v2\/posts\/11805\/revisions\/11808"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/wp.unil.ch\/geoblog\/en\/wp-json\/wp\/v2\/media\/11797"}],"wp:attachment":[{"href":"https:\/\/wp.unil.ch\/geoblog\/en\/wp-json\/wp\/v2\/media?parent=11805"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/wp.unil.ch\/geoblog\/en\/wp-json\/wp\/v2\/categories?post=11805"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/wp.unil.ch\/geoblog\/en\/wp-json\/wp\/v2\/tags?post=11805"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}