{"id":509308,"date":"2026-06-20T08:30:20","date_gmt":"2026-06-20T08:30:20","guid":{"rendered":"https:\/\/www.newsbeep.com\/ie\/509308\/"},"modified":"2026-06-20T08:30:20","modified_gmt":"2026-06-20T08:30:20","slug":"earths-first-land-animals-may-never-have-been-amphibian-like-after-all","status":"publish","type":"post","link":"https:\/\/www.newsbeep.com\/ie\/509308\/","title":{"rendered":"Earth\u2019s First Land Animals May Never Have Been Amphibian-Like After All"},"content":{"rendered":"

Paleontologists from the Field Museum of Natural History<\/a> have described the fossilized remains of baby embolomeres<\/a>, crocodile-like predators that prowled ancient rivers and swamps between 350 and 280 million years ago. These creatures were among the earliest land-dwelling vertebrates, and their babies, scientists had assumed, would look like tadpoles \u2014 but they don\u2019t.<\/p>\n

\"New<\/a><\/p>\n

New fossil evidence suggests that embolomeres did not undergo a metamorphosis the way that modern amphibians do when growing up, which challenges a long-standing scientific belief that amphibians, reptiles, and mammals evolved from animals that had a tadpole stage. Image credit: Berit Godring.<\/p>\n

\u201cWhen a lot of us were in high school, we were taught this simplified story of evolution: that some fish evolved into amphibians, and some of those amphibians evolved into reptiles, and some of those reptiles evolved into mammals,\u201d said Field Museum paleontologist Jason Pardo.<\/p>\n

\u201cAnd our study shows that this basic underlying premise, that the first four-legged vertebrates grew up like amphibians, is wrong.\u201d<\/p>\n

In their new research, Dr. Pardo and his colleague, Dr. Arjan Mann, looked at tetrapod fossils, many with well-preserved soft tissues, from the Mazon Creek Lagerstatte in Illinois.<\/p>\n

\u201cIt\u2019s one of the best fossil sites in the world, especially for soft tissues and delicate little fossils,\u201d Dr. Mann said.<\/p>\n

\u201cMazon Creek fossils are time capsules that capture the impossible.\u201d<\/p>\n

As adults, embolomeres could stretch over 3 m (10 feet) \u2014 fearsome apex predators that lived in rivers, lakes, and swamps from 350 (Carboniferous period) to 280 million years ago (Permian period).<\/p>\n

The Mazon Creek specimens are a humbling contrast: babies just a few cm long, yet carrying enough information to overturn a century of scientific assumption.<\/p>\n

According to the authors, the baby embolomeres were missing key amphibian tadpole traits like frilly external gills.<\/p>\n

Even when larval stages underwent big changes on their way to adulthood, they showed no signs of true amphibian metamorphosis.<\/p>\n

Instead, these early tetrapods\u2019 life cycles appear to be more like ours \u2014 or like those of fish \u2014 than like amphibians.<\/p>\n

\u201cWe looked at a number of different species that represent different lineages in the transition from fish to tetrapods, and what we found is that none of them have anything that looks remotely like a tadpole,\u201d Dr. Pardo said.<\/p>\n

\u201cAnd if you don\u2019t have a tadpole, then you don\u2019t have a metamorphosis.\u201d<\/p>\n

\u201cAnd if animals like embolomere didn\u2019t have a tadpole form or a true amphibian metamorphosis, that means that the widely-accepted hypothesis that reptiles and mammals evolved from amphibian-like animals is incorrect.\u201d<\/p>\n

\u201cThe story was that metamorphosis is the tool by which animals made the transition from fossil to land. That story doesn\u2019t work anymore, it\u2019s dust in the wind.\u201d<\/p>\n

The findings<\/a> appear in the journal Science.<\/p>\n

_____<\/p>\n

Jason D. Pardo & Arjan Mann. 2026. Direct development of stem tetrapods across the fin-to-limb transition. Science 392 (6804): 1292-1296; doi: 10.1126\/science.aeb7635<\/p>\n","protected":false},"excerpt":{"rendered":"Paleontologists from the Field Museum of Natural History have described the fossilized remains of baby embolomeres, crocodile-like predators…\n","protected":false},"author":2,"featured_media":509309,"comment_status":"","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[7],"tags":[112669,25393,217515,217516,9155,61,12557,60,217517,11310,7891,65728,82,217518,217519,139646,115],"class_list":["post-509308","post","type-post","status-publish","format-standard","has-post-thumbnail","category-science","tag-amphibian","tag-carboniferous","tag-embolomere","tag-embolomeri","tag-fossil","tag-ie","tag-illinois","tag-ireland","tag-mazon-creek","tag-metamorphosis","tag-north-america","tag-permian","tag-science","tag-stem-tetrapod","tag-tadpole","tag-tetrapod","tag-united-states"],"_links":{"self":[{"href":"https:\/\/www.newsbeep.com\/ie\/wp-json\/wp\/v2\/posts\/509308","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.newsbeep.com\/ie\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.newsbeep.com\/ie\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/ie\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/ie\/wp-json\/wp\/v2\/comments?post=509308"}],"version-history":[{"count":0,"href":"https:\/\/www.newsbeep.com\/ie\/wp-json\/wp\/v2\/posts\/509308\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/ie\/wp-json\/wp\/v2\/media\/509309"}],"wp:attachment":[{"href":"https:\/\/www.newsbeep.com\/ie\/wp-json\/wp\/v2\/media?parent=509308"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.newsbeep.com\/ie\/wp-json\/wp\/v2\/categories?post=509308"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.newsbeep.com\/ie\/wp-json\/wp\/v2\/tags?post=509308"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}