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Scientists Find 'Oldest Human Ancestor' -- A Big-Mouthed Sea Creature With No Anus (bbc.com) 136

An anonymous reader quotes a report from BBC: Researchers have discovered the earliest known ancestor of humans -- along with a vast range of other species. They say that fossilized traces of the 540-million-year-old creature are "exquisitely well preserved." The microscopic sea animal is the earliest known step on the evolutionary path that led to fish and -- eventually -- to humans. Details of the discovery from central China appear in Nature journal. The research team says that Saccorhytus is the most primitive example of a category of animals called "deuterostomes" which are common ancestors of a broad range of species, including vertebrates (backboned animals). Saccorhytus was about a millimeter in size, and is thought to have lived between grains of sand on the sea bed. The researchers were unable to find any evidence that the animal had an anus, which suggests that it consumed food and excreted from the same orifice. The study was carried out by an international team of researchers, from the UK, China and Germany. Among them was Prof Simon Conway Morris, from the University of Cambridge. The study suggests that its body was symmetrical, which is a characteristic inherited by many of its evolutionary descendants, including humans. Saccorhytus was also covered with a thin, relatively flexible skin and muscles, leading the researchers to conclude that it moved by contracting its muscles and got around by wriggling. The researchers say that its most striking feature is its large mouth, relative to the rest of its body. They say that it probably ate by engulfing food particles, or even other creatures. Also interesting are the conical structures on its body. These, the scientists suggest, might have allowed the water that it swallowed to escape and so might have been a very early version of gills.
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Scientists Find 'Oldest Human Ancestor' -- A Big-Mouthed Sea Creature With No Anus

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  • Like I told my kid the other day, "You might be a descendant of a big-mouthed sea creature with no anus, but I certainly am not!"

  • Pretty sure that guy sits a few cubes over.
  • by MrKaos ( 858439 ) on Monday January 30, 2017 @09:00PM (#53770449) Journal

    The evidence for why some people talk out of their anus.

  • by jfdavis668 ( 1414919 ) on Monday January 30, 2017 @09:01PM (#53770469)
    I know this comes later in evolution, but doesn't the first orifice for the anus, and the second the mouth in a deuterostome? I realize this creature has only one opening, so it uses it for both. If so, it shouldn't be called a "big mouthed sea creature with no anus" but a "big anus sea creature with no mouth."
    • by Anonymous Coward
      What comes out the anus if it has no mouth?
    • by shoor ( 33382 ) on Monday January 30, 2017 @10:16PM (#53770909)

      So far, jfdavis668 is the only person to make a sensible comment. (As opposed to some lame, obvious, snarky, schoolboy type joke.)

      I was thinking about that deuterostome angle myself. I wondered if this critter was supposed to be before the deuterostome/protostome split. But they explicitly say in the article that it is a deuterostome. Well, the article didn't say there was no anus, just that they hadn't found one (yet).
      .

      • by AmiMoJo ( 196126 )

        Years ago I was watching a TV show where a professor was arguing that a nothing could live in a 2D universe because there would be no way for it to feed, as feeding required both a month and an anus. I thought it sounded wrong at the time, why not just regurgitate waste through the mouth? I must have been pretty young at the time, but it's kinda nice to get confirmation all these years later.

    • by Anonymous Coward

      You are 100% correct.
      [ Insert rant about science journalism here. ]
      (Seriously though, the article just missed a great opportunity to educate and make people think for no good reason.)

    • I thought that the "embryo development parallels/replays evolution" thing was a myth? So the anus forming first in the embryo has nothing to do with when it first evolved.

      (This shouldn't be confused with studying similarities in embryo development to infer evolutionary relationships.)
      • by jfdavis668 ( 1414919 ) on Tuesday January 31, 2017 @10:29AM (#53773619)
        This is the biological definition of deuterostomes. As the embryo changes from a mass of cells to an organized body, the mass starts to cup and folds around to form an internal cavity. This becomes the body cavity. The hole left eventually becomes the anus. The mouth forms later. All deuterostomes form this way till today, including all chordates/vertebrates and sea stars and related other sea creatures. Protostomes do the opposite, the initial hole becomes the mouth. These are the arthropods and mollusk and the like. It is not an evolutionary hold over, but the body forming process that continues to this day.
        • You seem to be implying that just because the embryo of deuterostomes develops the anus first, that somehow means that orifice must have evolved first. That is an incorrect assumption.

          Just because the anus forms first in the embryo does not necessarily mean that the embryo of a proto-deuterostome used that same hole "first" before evolving the second one. Embryo development itself changes with evolution; there's no reason to suspect that each evolutionary step could only add features onto the very end of
          • The paper is not calling this a proto-deuterostome, it calls it a deuterostome. To fit the definition of deuterostome, the first hole evolves into the anus of all decedents. If that is not the case, the paper is using the wrong terminology.
            • To fit the definition of deuterostome, the first hole evolves into the anus of all decedents.

              Citation needed. The definition of deuterostome as I understand it is that the first hole that the embryo develops eventually turns into the anus. The definition of deuterostome makes no claim about whether the anus-hole or mouth-hole evolved first. Evolutionary development is not synonymous with embryological development.

              The fact that all organisms that have embryos which follow this sequence of development share a common ancestor does not necessarily mean that this hole was the one that first appeare

        • Although they have 45 specimens, they only range over a little more than a factor of 2 in size, and seem to be a single size distribution. Or, to put it another way, only one part of the life cycle of these organisms has been identified and assigned to this organism (there may be other parts of the life cycle in recovered samples, but they haven't been assigned to this morphological species ; it's a general problem in palaeontology).

          Latest-Ediacaran ("Neoproterozoic" - terminology has changed over time) me

    • 200 million years from microscopic devil (devils have no anus), to Dinosaurs? Arent these people lost in fake figures? I guide myself by what I learned when I was five, I dislike how time is being shortened recently in this matter... I see a forced guideline behind this to avoid having people lost in time so everything had to just have happened in this civilization recently irregardless...
  • So... these were the evolutionary ancestors of the Slaver race? (From Larry Niven's Known Space stories)

  • Must ... resist ... Trump ... jokes ...

  • by Wraithlyn ( 133796 ) on Monday January 30, 2017 @09:08PM (#53770511)

    A gaping mouth and a weird posterior...

    AND NOT A SINGLE MOM JOKE ANYWHERE?

    Internet, I am disappoint.

  • Not that fun wouldn't be had with this subject any time, but I think this week was a particularly poor time to post this article.
  • by PPH ( 736903 ) on Monday January 30, 2017 @09:19PM (#53770565)

    ... to grow an anus. And now the mouth and anus are difficult to tell apart.

  • researchers discovered a complete anus with a mouth at 1600 Pennsylvania Avenue.
  • âoeThe Talking Asshole Routineâ from Naked Lunch

    William S. Burroughs

    Did I ever tell you about the man who taught his asshole to talk? His whole abdomen would move up and down you dig farting out the words. It was unlike anything I ever heard.

    This ass talk had sort of a gut frequency. It hit you right down there like you gotta go. You know when the old colon gives you the elbow and it feels sorta cold inside, and you know all you have to do is turn loose? Well this talking hit you right down there,

  • Swinging at the low hanging fruit since 1968

  • by InterGuru ( 50986 ) <jhd.interguru@com> on Monday January 30, 2017 @11:29PM (#53771333) Homepage

    At level 2 and above, I saw 22 comments, only three of which were serious. The comments by jfdavis668 and associated replies.

    If this continues, I will just stay off the site.

  • It's is older and also an ancestor
    • [Jealous]

      My stromatolite is only a billion (maybe up to 1.2 billion) years old. It's not far structurally below a meteor impact ejecta layer though, so it's descendants probably died in an interesting way.

      • I have a slab of Acasta (sp?) gneiss too. :) (I was bored one day on ebay)
        • Ah, but I collected my stromatolite samples from the field a couple of hours and a cold lunch after a morning of clambering over the impact ejecta sheet. No eBay involved.

          I did use eBay for my meteorite slab - Brennan Pallasite. And rust fragmented it in a couple of years. Verily does the universe extract it's revenge.

          • Haha. Sounds like more fun than ebay. I'm an engineer, not a paleontologist or geologist, but I used to work for some
            • Most of the people on the weekend trip (we did other geological stuff the previous day) were non-geologists too. The trip was led by a professor who worked on the meteorite impact structure (whose accommodation and travel costs we paid) ; I'm a professional geologist who is paid to look at uninteresting sludge ; the trip organiser was a school geography teacher. About 1/3 of the others were mature students of some sort (geology, geography, oceanography). the rest - just Joe Random Soap (including spouses an
  • I know; the temptation is undeniable, but resist. I'd like just one slashdot story without a "my guy is bigger than your guy" political flamewar.
  • by Anonymous Coward

    On what basis do we know this is the "oldest human ancestor", even theoretically?

    What evidence is there that history is:

    Saccorhytus -> ... -> Human ...rather than...

    Saccorhytus -> ... -> extinction

    Some earlier organism -> something vaguely similar to Saccorhytus -> ... -> Human

    Is there actual evidence for the first scenario over the second, or is this basically "sciencey clickbait"?

    • "Earliest ancestor" is a bit of scientific short hand. In long form it means "the fossil we've found is related to and a lot like we expect the earliest ancestor to appear." The odds of any fossil we find actually being that of a direct ancestor of any extant population is pretty small, but it isn't a vast leap to state that seeing that this earliest known deuterostome was hanging out in the sand 500-odd million years ago, it was likely representative of the earliest members of the superphylum, and the actu

    • Actually, your offerings do not jibe with how evolution happens .. Eg, a gorilla did not evolve to be homo sapiens : Rather, a PRECURSOR of the gorilla evolved to be a PRECURSOR (most likely) of humans .. So, Saccorhytus did NOT evolve to be human ... That is the basis for the general design of the 'evolutionary tree' ..
  • .. but I've never had a supervisor direct me to find an anus, and therefore I've never had to report to a supervisor "Sorry, couldn't find it."
  • If you thought Creationists had fits over the idea we're descended from primates, just imagine how much of a conniption fit they'll have over this.
  • ... assholes appeared only in recent times. Back then creatures were more civilized.

  • by Anonymous Coward

    It's Pac-Man

  • I think whoever did the artist's concept must have been an LOTR fan.

  • Wait for it..... Donaldus Trumpus although Hilarus Clintus came in second....
  • From the data: "The researchers were unable to find any evidence that the animal had an anus, which suggests that it consumed food and excreted from the same orifice." https://slashdot.org/ [slashdot.org] it appears that a more-relevant name might be Republicanus Fascisti
  • To paraphrase Harlan Ellison, "I have no anus, and I must shit."

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