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Science

190 Million Year Old Dinosaur Embyro 170

Posted by Zonk from the old-little-thing dept.
leprasmurf writes "Sci Tech Today is reporting that scientists have cracked open a 190-million-year-old egg to reveal the oldest known dinosaur embryo. Examination of the fetal skeleton suggests the hatchling would have required parental care to survive. This would be the earliest evidence of nurturant behavior, more than 100 million years earlier than previous examples." The University of Toronto has a release about this as well. From the article: "According to Reisz, what makes this discovery particularly significant is the ability to put the embryos into a growth series and work out for the first time how these animals grew from a tiny, 15 centimetre embryo into a five metre adult. 'This has never been done for a dinosaur. Only Massospondylus is represented by embryos as well as by numerous articulated skeletons of juveniles and adults. The results have major implications for our understanding of how these animals grew and evolved,' he says."
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190 Million Year Old Dinosaur Embyro More

190 Million Year Old Dinosaur Embyro

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  • What methods are used to accurately measure the age of these discovered items? I see wildly different estimates on similar things, depending on who's getting the grant to tell me about it.

    • Re:Dating Methods (Score:4, Funny)

      by Z4rd0Z ( 211373 ) <joseph at mammalia dot net> on Friday July 29, 2005 @11:23PM (#13200469) Homepage
      Well, we know the earth is no more than 6,000 years old, so any measure that veers too far off that is bound to be inaccurate. The most accurate known dating method is counting backwards through the geneologies in the book of Genesis. Unfortunately, this egg is not mentioned there, so we'll probably never know its true age.

      • Re:Dating Methods (Score:4, Funny)

        by Thunderstruck ( 210399 ) on Friday July 29, 2005 @11:30PM (#13200496)
        To be fair, not all biblical literalists think this 6000 year number is anywhere near accurate. Many accept values between 10 and 30 thousand years. In any case, while I don't buy into evolution personally*, I can't help but wonder why I don't ever see ID or creationist fossil research publications. Don't church-supported universities also engage in this kind of research? Even the 6000 year crowd must surely be interested in knowing how these dinosaurs lived.

        Any thoughts?

        * I am origin agnostic, I haven't seen a good scientific theory yet for how things got here.

        • Re:Dating Methods (Score:1, Insightful)

          by l3ert ( 231568 )
          To be fair, not all biblical literalists think this 6000 year number is anywhere near accurate. Many accept values between 10 and 30 thousand years.
          So what? Between 10 and 30 thousand years is as retarded as 6000. Life on earth began billions of year ago.

        • Re:Dating Methods (Score:5, Insightful)

          by Anonymous Coward on Friday July 29, 2005 @11:45PM (#13200544)
          Umm, evolution is origin agnostic. It doesn't explain how life started, just what happened once it did.
          • Crap, no mod points. Excellent point!
          • "Umm, evolution is origin agnostic. It doesn't explain how life started, just what happened once it did."

            Actually, the idea of Universal Common Ancestry, which most people think of when they talk about evolution, is predicated on a specific notion of abiogenesis. Without a specific theory of abiogenesis, there is not really a reason or evidence to think that all are related, especially given the fossil record.

            If by evolution, you mean simply "change", then yes, every agrees in evolution, even the 6-day cre
            • Without a specific theory of abiogenesis, there is not really a reason or evidence to think that all are related, especially given the fossil record.

              Sure there is. DNA similarities for starters.
              • Actually, DNA would point you in the other direction. Being that there are multiple DNA codings, it is unlikely for them to be ancestral to each other since a change in the coding would render most of the existing genome useless.

                The DNA and RNA comparisons past the family taxonomic level lead to utter confusion.

                The fact that everything has DNA is like saying every program has an initialization stage, a loop, and a finalization stage. It's true, but it doesn't mean much, especially if there was a common de

            • > > Umm, evolution is origin agnostic. It doesn't explain how life started, just what happened once it did.

              > Actually, the idea of Universal Common Ancestry, which most people think of when they talk about evolution, is predicated on a specific notion of abiogenesis.

              No, it isn't.

              The notion of common descent doesn't say anything about how abiogenesis happened, nor even how many times it happened. It only says that we're all related to some common ancestor, which may or may not have been the only thi

        • Re: Dating Methods (Score:5, Insightful)

          by Black Parrot ( 19622 ) on Friday July 29, 2005 @11:49PM (#13200552)


          > To be fair, not all biblical literalists think this 6000 year number is anywhere near accurate. Many accept values between 10 and 30 thousand years.

          Wow, that means they're only... well, still 4.5 billion years off.

          > In any case, while I don't buy into evolution personally ... am origin agnostic, I haven't seen a good scientific theory yet for how things got here.

          Why don't you buy into evolution? And when you mention "how things got here" are you talking about biology, or cosmology?

          > I can't help but wonder why I don't ever see ID or creationist fossil research publications.

          ID isn't interested in any kind of research. They just want you to hear their "proofs" that God^w some incredibly powerful intelligent being created us - no questions from the audience, please. (Though they have been stung enough by our pointing out that real scientists publish in the peer reviewed literature that they're trying to make some end runs on peer review so they can claim that they've published in it.)

          As for other kinds of creationists, some do take interest in explaining dinosaurs. Everything from carving fake human footprints among the Paluxy dinosaur tracks to having clueless amateurs excavate priceless specimens. And I think Ken Ham has a dino museum now.

          Though their notion of research publications is - hard to imagine - even worse than the IDists'.

          • Why don't you buy into evolution? And when you mention "how things got here" are you talking about biology, or cosmology?

            To me, it seems a choice between the infinitely improbable and the utterly unprovable. Must we rely solely on either science or philosophy to understand our world?

            I don't buy into evolution for the litany of reasons that creationists give to "prove" creation. I'm sure you've heard them all. Of course none of these flaws prove creation, but they leave enough holes that I won't sign onto

            • Re: Dating Methods (Score:4, Insightful)

              by Anonymous Coward on Saturday July 30, 2005 @12:22AM (#13200647)
              I don't buy into evolution for the litany of reasons that creationists give to "prove" creation.

              Those reasons are bogus. Even the Pope has given up and accepted that the fossil record is pretty conclusive and hence evolution is true. Only a few misguided fundementalists in America stick to this ridiculous literal interpretation of the bible.
              • "Even the Pope has given up and accepted that the fossil record is pretty conclusive and hence evolution is true."

                This is based on a misreading of the pope's statements.

                See Finding Design in Natura [nytimes.com]
                • This is based on a misreading of the pope's statements.

                  From http://www.catholic.net/RCC/Periodicals/Dossier/01 02-97/Article3.html [catholic.net]:

                  In his talk to the Pontifical Academy of Sciences, the pope reportedly stated that evolution is "more than a hypothesis." At first, some critics of evolution argued that the pope was mistranslated into English here. What he really said, they argued, was that "new knowledge has led to the recognition of more than one hypothesis in the theory of evolution."Even the English languag
                  • "it seems clear that the pope thinks evolution is supported, at least to some extent, by the evidence."

                    _Everyone_ thinks that evolution is supported, at least to some extent, by the evidence. 6 day creationists included.

                    The article I referenced doesn't even include the translation you are referring to. Instead, it includes the pope's words in context with everything else he has said, such as:

                    "It is clear that the truth of faith about creation is radically opposed to the theories of materialistic philosoph
            • there were a LOT more "reasons" and holes. They keep falling. In another 100 years, I think that almost all will be gone.
            • Of course none of these flaws prove creation, but they leave enough holes that I won't sign onto the theory.

              Perhaps you could name some of these "flaws"? Oftentimes many "flaws" that creationists identify in the theory of evolution are actually products of creationist misunderstanding or -- in many cases -- their outright dishonesty.
          • to come along and contradict.)

            They're all anti-media as far as that goes. They have "the book", you should learn "the book" by heart, but only to recite, not to interpret, that's a job for the priesthood.

        • Don't church-supported universities also engage in this kind of research?

          This is the dumbest thing ever. You either have faith or you don't. If you do research to try and prove you're in some way correct in your faith, you totally defeat your whole argument.

          You don't need research if you have the bible. Everything you need to know is right there in the book.

          Stupid stupid stupid. I hate having conversations about what research has been done to back up the bible theory. "Oh well there's only 3 feet of silt o
          • I think you missed the point of my question. Even bliblical literalists like to know how things work. I know several that work in biological research at universities. They're not trying to prove what their faith teaches, they're trying to learn how the world around them works.

            I hadn't heard about the silt thing though, thats interesting.
            • Didn't mean to rant specifically to you. I had just had a discussion with some random guy who was trying to make arguments, such as the silt one, as proof that the bible is right and pure fact.

              Just annoys me :)

          • Re:Dating Methods (Score:3, Informative)

            by johnnyb ( 4816 )
            "This is the dumbest thing ever. You either have faith or you don't. If you do research to try and prove you're in some way correct in your faith, you totally defeat your whole argument."

            Actually, modern science arose mostly from Biblical creationists trying to learn more about the world. The difference between a Biblical creationists and a secular scientists, is that a Biblical creationist will trust the Bible to be a valid starting point. You seem to be confusing having a solid starting point with also
            • Interestingly, during the dark ages it was the christian church that protected much of science and scientific writings.
              I can't reference on google at the moment.. too many "christian science" hits.

        • Re:Dating Methods (Score:5, Funny)

          by XFilesFMDS1013 ( 830724 ) on Saturday July 30, 2005 @12:10AM (#13200618)
          I can't help but wonder why I don't ever see ID or creationist fossil research publications.

          Waiting for this kind of reasearch is like waiting for Duke Nukem Forever to be released. Need I say more?
        • what you call "Evolution" isn't about origins, it's simply the leading theory to explain the fact that life forms have changed and adapted over time. it is nothing to do with how life got here in the first place. ID proponents don't have fossil research publications for the same reason that circus clowns don't. personally, i think you should head down to your local library and pick up some introduction to biology books. Darwin's Ghost by Steve Jones is a good place to start, and it's a fun read to boot.

          • [The theory of evolution has] nothing to do with how life got here in the first place.

            But it does. A theory that cannot predict the past is difficult to trust.

            The thing is, evolution can predict the ancient past, up to a point. By comparing a variety of modern species, we can predict how their common ancestors were built. (In a few happy cases we can actually test the predictions.) But look back far enough and you see a black wall. Things like ribosomes and amino-acyl tRNA synthases* simply cease to h

        • Re: Dating Methods (Score:3, Interesting)

          by Black Parrot ( 19622 )

          I forgot to respond to this:

          > Don't church-supported universities also engage in this kind of research?

          I think most of them stick to real science. Even at Baylor U (affiliated with the Southern Baptists, IIRC) the science faculty threw a fit when the university president tried to set up one of the leading ID "researchers" with a position lending a false sense of scientific respectability to his views.

          (FWIW, he finally landed in the Theology department at another university.)

        • Re:Dating Methods (Score:2, Insightful)

          by bm_luethke ( 253362 )
          "To be fair, not all biblical literalists think this 6000 year number is anywhere near accurate. Many accept values between 10 and 30 thousand years."

          I don't know wether one would consider me a literalist or fundamentalist or not. I, personally, consider myself a pretty hardline Christian that doesn't particularly prescribe to any one denomination (all I know of are corrupt). I prefer to read the Bible and make up my own damn mind, plus I like to read other religious text and make up my own damn mind if the

          • Re:Dating Methods (Score:2, Insightful)

            by EdipisReks ( 770738 )
            while i find your overall post to be overall quite worthwhile, BM Luethke , i find the line about disbelief and and belief in a creator being equal despite evidence to be rather humorous. if one is going to take a rational, scientific approach to analysing the material world, the default state must be skepticsm. there is no concrete evidence of a creator, so disbelief is the only rational position. while it is correct that the statement "there is no god" is no more valid than the statement "there is a go
          • What is commonly meant by evolution I support fully (however, evolution as a concrete thing has been shown to be wrong, there are more modern theories that better fit the data set.

            By which you mean....?
        • "I can't help but wonder why I don't ever see ID or creationist fossil research publications."

          The reason you don't see ID fossil research publications is that most people in the ID crowd have no problem with the standard interpretation of the fossil record. In additions, the methods of ID deal with systems, which are not present in fossils.

          Creationists do deal with fossils. The creationists are few enough in number that they don't have highly specialized publications, but they do have publications that in
          • They are opening a museum in Kentucky, and have a very talented Dinosaur modeller working for them.

            This would be the museum with the Triceratops with a saddle on its back?

      • My view (Score:4, Interesting)

        by RKBA ( 622932 ) * on Saturday July 30, 2005 @12:17AM (#13200632)
        Well, we know the earth is no more than 6,000 years old, ...

        Beware the Wrath of God! [dotson.net]

        Hosea 13:16: [skepticsan...dbible.com] Samaria shall become desolate; for she hath rebelled against her God: they shall fall by the sword: their infants shall be dashed in pieces, and their women with child shall be ripped up.
      • Comment removed based on user account deletion
    • you type in your question into the little searchbox, and out come 50 billion answers.

      from http://www.caspercollege.edu/tate/faq_24.htm [caspercollege.edu]

      "We can get an idea of how old dinosaur bones are relative to each other by using the principles of stratigraphy. Here's an example: The bones of Deinonychus are found in the Cloverly Formation. In another formation, the Thermopolis Shale, we find the bones of a different dinosaur, Nodosaurus. Whenever the two formations are found in the same area, the Thermopolis Shale is al


    • as we can see [answersingenesis.org] (scroll to "Different dating techniques should consistently agree" heading), radiometric dating techniques often leave quite a bit to be desired.

      At any rate, the date is far less important in this discovery than the implications it raises about the maturation of dinosaurs.
      • Answers in Genesis ain't the best source for critiquing radiocarbon dating. See, for instance, this critique [talkorigins.org] of some of the research of Steve Austin, who AIG quotes.

        The thing is, radioisotope dating for a sample will be invalid if the sample is bad. This is pretty well know. Austin likes to pick bad samples and then claim the whole system is bad.

        To make a lame analogy, let's say you're trying to find the average weight of an egg. Austin comes in, sees that you've broken a few, and tells you that your sc

      • Not sure that I would use these [answersingenesis.org] guys as a credible referance.

        • > Not sure that I would use these [answersingenesis.org] guys as a credible referance.

          Especially given their Statement of Faith [answersingenesis.org]. Notice in particular the final item:

          By definition, no apparent, perceived or claimed evidence in any field, including history and chronology, can be valid if it contradicts the Scriptural record.

          They excuse that position on the grounds that "evidence is always subject to interpretation by fallible people who do not possess all information", though they do not seem to hold the

    • Dating methods?

      Dinosaurs prefer to enjoy an evening of fine dining and wine, followed by a moonlit walk on the beach, followed by some dirty talk about the Cretaceous era. After this, the female dinosaur may invite the male dinosaur over for a cup of coffee and the creative use of a clit-tickler.

    • Whatever methods they use, I am plainly too lazy and tired to try and find out. However once they do find out some great soul will surely inform us here.

      As is it we are still trying to figure out whether man ever went to the moon.

    • What methods are used to accurately measure the age of these discovered items? I see wildly different estimates on similar things, depending on who's getting the grant to tell me about it.

      Here's a link [cartage.org.lb].

      Mostly it's by dating of carbon or radioactive elements, and determining where in the rock strata the fossils were found.

  • Old News (Score:5, Funny)

    by Anonymous Coward on Friday July 29, 2005 @11:16PM (#13200440)
    Pah. This is old news.

    no really...it is.

  • How about a picture? (Score:3, Insightful)

    by Z4rd0Z ( 211373 ) <joseph at mammalia dot net> on Friday July 29, 2005 @11:17PM (#13200445) Homepage
    <osnews>
    Does anyone have a screenshot?
    </osnews>

    Seriously though, a picture would be nice.

  • Kinda wierd how this story goes hand in hand w/ today's big stem cell announcement ;)..

  • Does this mean... (Score:4, Funny)

    by TapeCutter ( 624760 ) on Friday July 29, 2005 @11:19PM (#13200458) Journal
    ...they have cracked the mystery of Dinosaur development.
  • Elephants grow from tiny embryos into huge animals, too...

  • The nurturing wouldn't be surprising (Score:5, Insightful)

    by ReformedExCon ( 897248 ) <reformed.excon@gmail.com> on Friday July 29, 2005 @11:25PM (#13200478)
    Considering that modern birds are almost all nurturers of their young, it stands to reason that dinosaurs, the precursors to birds, would also have exhibited nurturing behaviors towards their hatchlings. On the other hand, reptiles, the other modern descendant of the dinosaurs by and large do not nurture their young, some, like the green sea turtle, lay their eggs in the sand and never see the babies again.

    I wonder how much nurturing had a part in the evolution of birds and reptiles. Whether the nurturing behavior in early birdlike dinosaurs led to the modern birds of today. And whether the non-nurturing behavior of other dinosaurs led to the separate branch which is populated by modern-day reptiles.

    But the question on everyone's mind is, how tasty are those embryos?
    • I bet they taste like chicken.
    • Just a nitpick. While birds may be direct descendants from one lineage of dinosaurs, dinosaurs trace ancestry from reptiles.

      Also, nurturing had a part in the evolution of bird species in so much as any other adaption helped. Evolution proceeds by natural selection based on random variation. That is, if nurturing conferred a selective advantage, then the organisms that expressed nurturing traits would tend to reproduce and propagate the genes.

      I'm not sure if it is thought that mammals descended from d
      • That'd be common (insert appropriate reptilian pre-dinosaur family here) ancestor, since the evidence suggests that the last common ancestor of dinosaurs and mammals came well before there were dinosaurs.

      • Re:The nurturing wouldn't be surprising (Score:2, Interesting)

        by Anonymous Coward
        I don't think you can say absolutely that a trait that exists must confer a selective advantage. There may be traits that accompany other advantageous traits but that do not confer any advantage in and of themselves. So if nurturing was somehow genetically programmed into these dinosaurs, there may have been other traits such as feathered limbs that simply came along for a ride.

        Mutations on the microscale are hardly what you could call advantageous to any specific creature. It isn't until these mutations
        • Absolutely agree that many mutations do not confer an immediate selective advantage. Also, some phenotypes that may be advantageous in one environment may become disadvantageous if the environment changes.

          I'm hardly an expert at evolutionary biology, merely an interested amateur. However, I think that for a trait to persist over millenia, there must be some long term survival advantage to it.
        • I don't think you can say absolutely that a trait that exists must confer a selective advantage.
          Well, we're in luck because nobody said that!

          So if nurturing was somehow genetically programmed into these dinosaurs, there may have been other traits such as feathered limbs that simply came along for a ride.
          That's a really bad example. Feathers are very expensive to make. Unless there is an advantage to having them, they won't get made. I'm not sure I follow this notion of "tag along traits" that have no se

      • Just a nitpick. While birds may be direct descendants from one lineage of dinosaurs, dinosaurs trace ancestry from reptiles.

        True. But we have to remember that by the end of the Cretaceous the Dinosaurs and Reptiles had been separate for a very long time. There is no reason why we should expect dinsoaurs to resemble reptiles, just as we don't expect mammals to be reptillian.

      • A nitpick of your nitpick (Score:3, Interesting)

        by jd ( 1658 )
        It is now being debated as to whether it is strictly correct to say dinosaurs evolved from reptiles, or whether it would be more correct to say they evolved from a common ancestor. The typical evolutionary chart shows dinosaurs and reptiles diverging with a common ancestoral grouping of "Archosauria" and NOT being directly related at all.

        Part of the problem is that there are really very few points of similarity. Dinosaurs were warm-blooded, had medullary bone and laid eggs individually. None of this is true

        • I'm not sure how useful the term reptile still is, at least to scientists in determining common descent, since as I recall from grammer school it applied to all cold blooded vertebrates with eggs with shells. The class reptilia is composed of four orders, squmata (lizards & snakes), crocodilia (crocs & gators), Rhynchocephalia (tuataras) and turtles (testudines).

          But these don't seem to be products of a single lineage other than being members of microphylum amniota. Back in the late paleozoic this
      • Mammals and Reptiles also have a common ancestor group, called Amniota. Evolutionary biology isn't my strongest subject, so someone else'll have to fill in the details, but a quick google suggests that the divergence occurs around about the time amniotic eggs evolved - which would kind-of make sense with the common ancestor.


        But the answer to this part seems to be that mammals and reptiles evolved largely independently and not from one another.

      • many mammals also display nurturing

        I thought that was more or less required to qualify as a mammal. Check out the etymology.
    • Interesting point.

      I saw a show on Discovery a few days ago where they presented the theories on the development of the feathers. It is obvious that feathers developed before the ability of flight so what were they used for? According to the show feathers could be used to protect (and keep warm) the eggs when nesting. In my mind, it is a short step from nesting to nurturing the young, so perhaps the development of feathers and the bird-like behaviour of nurturing the young did evolve at the same time?

      N

    • Two slight nits to pick here. First, modern reptiles aren't descended from dinosaurs. They're descended from reptiles that lived at the same time as the dinosaurs, but were not themselves dinosaurs. Some of those reptiles still exist in a nearly unchanged form -- famously, the crocodilians, the turtles and the tuataras. Snakes and lizards, on the other hand, have changed quite a bit since then. Second, there are actually a few examples of reptiles that do nurture their young. It is common behaviour among
  • Elephant ebryo [elephant.se] and an elephant with an odd, second trunk. Where's this guy been today? =] [overheardintheuk.com]
  • "This is a UNIX system! I know this!"

  • Embryonic Bones & Actual Dinosaur Blood (Score:4, Interesting)

    by reporter ( 666905 ) on Saturday July 30, 2005 @12:26AM (#13200651) Homepage
    In a report titled "Scientists Discover T. Rex. Soft Tissue [msn.com]" distributed by NBC on its website, scientists have actually obtained the blood samples of the most famous dinosaur: Tyrannosaurus Rex. This fact, coupled with the rapid advances in genetic engineering, suggests interesting possibilities in the future.

    Even if scientists cannot extract the entire genetic code of dinosaurs from the blood samples, the scientists could make educated guesses. They then complete what, in their opinion, is the genetic code of a particular dinosaur. They then inject this code into a de-nuclearized egg of, say, a Komodo lizard to create a cloned embryo. Scientists can then use the embryonic fossilized bones to verify whether their guess is accurate. The scientists simply compare the fossilized bones with the bones of the developing embryo. If they are an exact match, then the scientists have likely cloned the genetic code of a particular dinosaur specimen.

    • Re: Embryonic Bones & Actual Dinosaur Blood (Score:4, Informative)

      by Black Parrot ( 19622 ) on Saturday July 30, 2005 @02:00AM (#13200844)


      > In a report titled "Scientists Discover T. Rex. Soft Tissue" distributed by NBC on its website, scientists have actually obtained the blood samples of the most famous dinosaur: Tyrannosaurus Rex.

      No, just "blood vessels", and even that is controversial. The apparently solid result is the discovery of medullary bone [naturalsciences.org] in the leg. Notice the abstract of the paper at the bottom of the link: no mention of blood, or even vessels.

      I think the claims about finding vessels is just a misunderstanding of the fact that bones have holes where the blood vessels run, and the medullary bone was found in those holes.

    • Imagine that you are able to extract 1/4 of the data from your file system. But, hey, it's no problem, loads of your friends also run Linux, so you can just take the missing bits from those. The only problem is that you used a very odd patch to 2.0, along with odd software package for almost everything else.

      Then, of course, it will matter a little how you fragment those around.

      No, you won't be able to make a "good" dinosaur clone. A single nucleotide at a certain position MAY affect only behavior, or skin

    • Then they could, say, dump it in the waters just off Tokyo to be nurtured by the local nuclear waste, causing great hilarity and movie remakes in years to come.

  • How would you feel? (Score:1, Insightful)

    by Anonymous Coward
    How would you feel to be the guy (or gal) who opened the egg? "Err, Hi, I'm Bob. This egg is 190 million years old. And I'm going to crack it open now."
  • writes "Sci Tech Today is reporting that scientists have cracked open a 190-million-year-old egg to reveal the oldest known dinosaur embryo.

    And then the embryo says; "Hey! Knock it off with all that cracking and the splitting. I'm trying to get some sleep in here. Say, you wouldn't happen to have some umbilical nutrients, or maybe a little left-over pizza, would you? Because I could use some anchovies."

  • I took classes with Dr. Reisz... (Score:4, Informative)

    by Fulg0re- ( 119573 ) on Saturday July 30, 2005 @03:05AM (#13200990)
    I had the opportunity to actually take several courses with Dr. Reisz several years ago at UTM, including my first introduction to human anatomy and physiology course. At the time, I was certainly surprised to learn about the homology that musculoskeletal systems had across species, even those separated by millions of years of evolution.

    I was also farily surprised to learn about some of the more optimal "solutions" that evolution came up with, including things such as the development of the cardiovascular systems ranging from say two-chambered hearts, to four-chambered hearts.

    It's also very sensible to presume that quadrapeds eventually evolved into bipeds in some dinosaur species. Of course, all we needed was proof for that assumption, and that's what this discovery was all about.

    Is it possible that the species found in the egg had congenital defects or was simply too small for its developmental age? Highly unlikely in my opinion. Too many other morphological factors involved.

  • Precocial or altricial? (Score:4, Informative)

    by TFGeditor ( 737839 ) on Saturday July 30, 2005 @08:05AM (#13201593) Homepage
    From the article: 'The third area, he said, is the most speculative. Some of the embryos were clearly ready to hatch, he said, but they have no teeth, "and that suggests to us that some form of parental care was required ... not just protecting but active feeding." '

    Speculating on whether hatchlngs were precocial or altricial based on absence of teeth is quite a stretch.

    Among birds, most birds that spend most of their time on the ground walking are born precocial (feathered, able to walk and feed minutes after hatching). Birds that spend most of their time in trees and flying are altricial (naked, unable to fly, walk, or feed themselves and hence need parental nurturing fore some time).

    However, coupled with other clues from the article, the altricial speculation seems more credible: "...the proportions of the limbs, neck and head suggest that as a baby and young animal this species walked on four legs, but as an adult it was able to walk on two legs some of the time." And, "...Mr. Reisz and colleagues reported that the Massospondylus hatchling was born four-legged with a relatively short tail, a horizontally held neck, long forelimbs and a huge head. As the animal matured, the neck grew faster than the rest of the body, but the forelimbs and head grew more slowly. The end result was a two-legged animal that looked very different from the four-legged embryo. Mr. Reisz suggested that the change from four- to two-legged could be a matter of balance related to the development of the animal's neck."

    The long neck suggests adult animals were browsers rather than grazers. As such, young clearly could not feed except on very low-growing shrubs. On the other hand, perhaps the young grazed during development and gradually adapted to browsing. If so, it further erodes the altricial speculation.

    Altricial young usually lack an ability critical to survival (e.g. flight among birds, foraging/hunting among mamallian carnivores and omnivores such as bears and chimpanzees) that involves both post-natal development and learning by minicry of the parents.

    Precocial young (common in most mammalian herbivores) have essential abilities (feeding, mobility--to feed, keep up with herd, escape predators) from birth often as an adaptation to allow "following the food." It therefore seems unlikely that an herbivorous species would bear altricial young because it would tie parents to a location during post-natal development, and the copious quantities of vegetation required by such large animals would deplete immediate-area resources rather quickly.

    Lack of teeth does not preclude suckling, another trait common among precocial herbivores.

    My vote therefore goes for precocial.

  • unless of course that's banned by dino-law...

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Top Ten Things Overheard At The ANSI C Draft Committee Meetings: (10) Sorry, but that's too useful.

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