Ancient Fish Fossil Reveals Transitional Link From Fins To Hands

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All tetrapods are believed to have evolved from crocodile-like Elpistostege watsoni fish that inhabited Earth during the Devonian period (Credit: Katrina Kenny/CC-BY-SA 2.0/The Conversation)

Researchers have long believed that all four-limbed animals or tetrapods, a group that includes amphibians, reptiles, and mammals, evolved from an ancient group of fish known as Elpistostege watsoni, which lived between 416 million and 358 million years ago, during the Devonian Period.

Over the years, partial remains of the creatures, which possessed characteristics of both lobe-finned fishes and tetrapods, has shed light on some of the anatomical change the creatures underwent, such as breathing, hearing, and feeding. However, the lack of a complete pectoral fin fossil had made it impossible to determine the evolution of one of the most important features for the transition — hands!

The perfectly-preserved E. watsoni fossil was found in Quebec in 2010 (Credit: Cloutier et.al)

Now, thanks to the pristinely-preserved remains of a 5-foot (1.57 meter) long E. watsoni specimen, scientists finally have some evidence. The 'missing link' was discovered in Miguasha National Park in Quebec, Canada, a treasure trove of animal fossils from the Devonian Period, in 2010. However, it was only recently that an international team of paleontologists from Flinders University in Adelaide, Australia, and Canada's Quebec University studied the remains in detail.

The pectoral fin of E. watsoni shows the short rows of aligned digits in the fin - an intermediate evolutionary stage between fishes and land animals, such as the early tetrapod Tulerpeton (Credit: Cloutier et.al)

The examination revealed that the crocodile-like creature, which lived in the shallow waters of an ancient estuary, had a flat head, long snout, and small round eyes. But it was the well-preserved pectoral fins that fascinated the scientists. Revealing the presence of phalanges, or phalanx bones, organized in digits (fingers), it provided the first evidence of finger-like bones that eventually evolved into hands. The discovery, published in the journal Nature on March 18, 2020, suggests that fingers in vertebrates originated in fish, rather than in later land dwellers

Study co-author Professor John Long, a paleontologist at Flinders University, says, "We believe this is the first evidence of digit bones found in a fish fin with fin-rays [the bony rays that support the fin]. This suggests the fingers of vertebrates, including human hands, first evolved as rows of digit bones in the fins of Elpistostege fishes."

E. wastoni , which lived during the Late Devonian period of Canada, is now considered considered to be the fish most closely related to
to tetrapods, a group that includes humans (Credit: Brian Choo/CC-BY-SA 2.0/The Conversation)

Quebec University 's Richard Cloutier, who led the research, believes the evolution to digits most likely began when the fish was starting to support its own weight in shallow water or on land. He says, "The increased number of small bones in the fin allows more planes of flexibility to spread out its weight through the fin." The researcher asserts the E. watsoni may not necessarily be our ancestor, "But it is the closest we can get to a true 'transitional fossil,' an intermediate between fishes and tetrapods."

Resources: theconversation.com, dailymail.co.uk

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224 Comments
  • gaelxx101
    gaelxx101Monday, October 19, 2020 at 11:45 am
    SUPER COOL!
    • kujityme-159578308584
      kujityme-159578308584Friday, October 16, 2020 at 2:08 pm
      #wow
      • kujityme-159578308584
        kujityme-159578308584Friday, October 16, 2020 at 2:05 pm
        That Was Awsome
        • destiny3250519
          destiny3250519Monday, October 19, 2020 at 12:08 pm
          i know so cool
        • newsgirlthe1st
          newsgirlthe1stMonday, October 12, 2020 at 7:13 am
          I wonder if alligators came from them.
          • 645345
            645345Monday, October 5, 2020 at 3:23 pm
            looks like a cartoon
            • deppressedfox20
              deppressedfox20Tuesday, October 13, 2020 at 1:15 pm
              Its not a cartoon its cgi Computer Generated Images
              • destiny3250519
                destiny3250519Tuesday, October 20, 2020 at 12:39 pm
                it so cool how you can do that with DNA and deppressedfox20 is corect
            • chrisyboigm
              chrisyboigmMonday, October 5, 2020 at 9:48 am
              This is So Cool!!!
              • coco8995
                coco8995Thursday, October 1, 2020 at 10:37 am
                i can't find the date for this anyone know help me out here??
                • fox1568
                  fox1568Monday, October 5, 2020 at 1:48 pm
                  APRIL 27, 2020
                • coco8995
                  coco8995Thursday, October 1, 2020 at 10:12 am
                  wow this is very weird but cool i think its unique!
                  • julsbe7
                    julsbe7Wednesday, September 30, 2020 at 11:49 am
                    That is really crazy and slimy. It is so weird, it doesn't even look real.
                    • deppressedfox20
                      deppressedfox20Tuesday, October 13, 2020 at 1:18 pm
                      Also not all reptiles or slimy most of them honestly aren't. Everyone always gets super confused about reptiles about being slimy and most all of them aren't even slimy
                      • deppressedfox20
                        deppressedfox20Tuesday, October 13, 2020 at 1:17 pm
                        That's because it isn't
                      • penguine
                        penguineTuesday, September 29, 2020 at 10:08 am
                        so slimy and cute looking.