Pharyngula

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Friday, April 15, 2005

A pelvis can say so much

Echoed on the Panda's Thumb

It's an impressive piece of detective work to take a fragment of a fossil and learn something about the behavior of dinosaurs. This is a fossil that consists of only the pelvic region of an oviraptor, which also happens to have a pair of large eggs nestled inside it. This poor female was pregnant at the time of her death, and was just about ready to lay these eggs.

It doesn't sound like much, but here's what we learn from it:

  • Oviraptors had two functional oviducts, like modern crocodiles. They laid their eggs in pairs.
  • These are large eggs, and the animal didn't have a lot of room in there—so it only laid a few at a time. It wasn't like modern sea turtles, dumping a load of eggs in a nest all at once.
  • Oviraptor nests have been found, and they contain many eggs. This had to have been done by repeated visits and multiple egg-laying sessions, suggesting a fair amount of parental investment in the nest.
  • The pointed end of the egg is pointed caudally. In oviraptor nests, the eggs are all in circular rings, with the pointed end outward. From this we can infer that the mother oviraptor stood in the center of the nest when laying the eggs.

Isn't it cool where a little evidence and logic will take you?

image
The oviraptorosaurian specimen at the National Museum of Natural Science in Taiwan (specimen no. NMNS-VPDINO-2002-0901) was excavated from the Upper Cretaceous Nanxiong Formation of the Hongcheng Basin near the city of Ganzhou, in the southern Jiangxi Province, China. It consists of six sacral vertebrae; the first two caudal vertebrae; the ilia, pubes, ischia, and femora; the lower part of the left leg; and a pair of eggs inside the pelvis. The pubes and ischia are slightly disarticulated, but otherwise these bones retain their original anatomical relationships. The eggs are located dorsal to the pubic symphysis, about one egg length anterior to the cloacal region. They are side by side and closely apposed, although the right egg was slightly more ventrally positioned than the left egg. Y.-n.C. and Y.-f.H. supervised the preparation of NMNS-VPDINO-2002-0901, confirming that it is not a composite.

Sato T, Cheng Y-n, Wu X-c, Zelenitsky DK, Hsiao Y-f (2005) A Pair of Shelled Eggs Inside A Female Dinosaur. Science 308(5720):375.


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Comments:
#22039: — 04/15  at  08:12 AM
When I was a child, I wanted to be a paleontologist (studying dinosaurs naturally). As a teenager I learned that vertebrate paleontology was a dead dead dead field. I gave it up for the stars. I don't exactly regret my decision, but on days like this I do feel a twinge......

Might cool stuff.



#22041: coturnix — 04/15  at  08:20 AM
Wow! I love stuff like this!

So much of dinosaur paleontology is focused on building cladograms. I get really excited when the fossils tell us something more than just position in the phylogeny, e.g., about the animals' physiology, behavior and ecology. This one is a real beauty.

[Just realized...this is just another in a series of vulva posts...]



#22042: Ron Sullivan — 04/15  at  08:57 AM
Some modern birds (What an odd phrase that is! The Jetsons' parrot?) have nests with many eggs laid by multiple females. These can be communal nests, like California acorn woodpeckers*, or nests involving many mothers and one putative father, like ostriches.

I'm not sure whether the orderly placement of the eggs you mention would suggest a Yes or No on this; it would be useful to populations if all females assumed a stereotypical posture, as that would conserve the other eggs. I suppose that's another of those metaquestions about the level on which evolution happens. I don't think the position of that oviraptor that was found over a nest sways things in either direction.

*In California, acorn woodpeckers have a more or less communist lifestyle. The Arizona population of the species lives in nuclear families. Wouldn't you know.



#22043: charlie wagner — 04/15  at  09:50 AM
This is not on topic, but this blog has a lot of readers and hopefully this message will get out. The Senate Majority Leader, Dr. Bill Frist has accused Democrats who oppose President Bush's judicial nominees of being "against people of faith". He also has agreed to join a handful of prominent Christian conservatives in a telecast portraying Democrats as "against people of faith" for blocking President Bush's nominees on April 24 to be called "Justice Sunday"
I faxed the following letter to Dr. Frist:

Dear Dr. Frist,
I find your statement that Democrats are “against people of faith” because they oppose President Bush’s judicial nominees and your alliance with the telecast sponsored by the “Family Research Council” to be deplorable and not in keeping with our constitutional mandate to keep church and state separate.
What you are saying is that the President’s nominees were selected because they reflect the values of “people of faith” and not because they are judicially qualified. This is not how our government should work. A person’s allegiance to a religious faith or lack thereof should NOT be a litmus test for his acceptability for the judiciary.
(signed)

I urge everyone who agrees with me to call (202-224-3344) or write ( Office of Senator Bill Frist
509 Hart Senate Office Building,
Washington, DC 20510
(fax if possible to 1-202-228-1264)

E-mails are not usually as effective as a phone call, letter or fax.

And if you have time, get a bunch of your friends to participate. You would be AMAZED at what kind of effect a few dozen letters or phone calls can have.

Thanks for your attention, now back to our regular programming...



#22044: — 04/15  at  10:02 AM
This may seem way off topic, but.. I am a cave diver. I found a very large very heavy thoughly mineralized pelvis in a thouroughly underwater cave in Florida. There are some other bones laying around beside the pelvis. The cave is in strata that are approximately 30 million years old based on fossils of kufu (clams) and ryncholampus (sea urchin) (all spelling extremely suspect). I always kind of thought I ought to do something about it, but I don't know what. I think the bones all probably fell out of the ceiling because of the mineralization. If I am wrong about the extent of mineralization (much easier to assess on dry land than while Scuba Diving 1000 feet from air) then the more logical conclusion would be to assume this is a much more recently deceased animal washed in from somewhere upstream. If I remove the pelvis without first marking and surveying the smaller bones I will never find those bones again. The bones are really heavy (like concrete) so moving them would take some serious effort. I further believe that collecting the bones and putting them on a shelf at my house (rather than in the hands of a competent professional) is almost criminal. Maybe I should just try to get really good photos. Thoughts?



's avatar #22045: PZ Myers — 04/15  at  10:14 AM
Take photos and bring them to your local university's biology department!

PZ Myers
Division of Science and Math
University of Minnesota, Morris



#22046: Hank Fox — 04/15  at  10:26 AM
Charlie, any link you can supply to allow verification would be appreciated.

Meanwhile, as to Frist, I say: Fuck him.

Instead of contacting Frist, contact your OTHER senators and representatives and say "This is the moment we've all been waiting for. They've finally overreached themselves, and it's time to shut these ridiculous and unAmerican bastards down. It's time to make a bold public statement that Frist and company are trying to turn America back to the time of Joe McCarthy, where loyalty oaths to THEIR idea of America are the test of whether or not any of us get to speak up and take part."

That could be worded better, but you get the idea. The point is that Frist and company are damaged goods. They wouldn't be where they are, politically, if they were capable of understanding the extreme anti-American nature of what they're doing.

They don't need to be pleaded with. They need to be taken down.

In my opinion, it's better to contact Democrats and moderate Republicans and plead with THEM: "Show some guts NOW while we still have an America to fight for."



#22048: charlie wagner — 04/15  at  10:32 AM
Hank Fox wrote:

" Charlie, any link you can supply to allow verification would be appreciated."

The story is on the front page of today's New York Times



#22049: Jeremy Osner — 04/15  at  10:34 AM
Oviraptor nests have been found, and they contain many eggs. This had to have been done by repeated visits and multiple egg-laying sessions, suggesting a fair amount of parental investment in the nest.


speaking as a layman -- wouldn't it more likely suggest communal nests? Eggs only stay eggs for a little while before they hatch -- if the nest contained multiple intact eggs then it seems like they wouldn't be the work of a single female.



#22051: Hank Fox — 04/15  at  10:39 AM
Charlie, ahem: I don't get the New York Times. Again, any LINK you can supply would be helpful. Work with me here; I'm just out of bed, pre-coffee, and feelin' lazy. smile

Meanwhile, a quote:

"It is contended by many that ours is a Christian government, founded upon the Bible, and that all who look upon the book as false or foolish are destroying the foundation of our country. The truth is, our government is not founded upon the rights of gods, but upon the rights of men. Our Constitution was framed, not to declare and uphold the deity of Christ, but the sacredness of humanity. Ours is the first government made by the people and for the people. It is the only nation with which the gods have had nothing to do. And yet there are some judges dishonest and cowardly enough to solemnly decide that this is a Christian country, and that our free institutions are based upon the infamous laws of Jehovah."

-- Robert Green Ingersoll, Individuality (1873)



#22054: charlie wagner — 04/15  at  10:46 AM
Hank,

http://www.nytimes.com



#22056: — 04/15  at  10:53 AM
Charlie,

Thanks for the heads up. I wrote to Frisk encouraging him to continue standing up for the majority of Americans who're sick and tired of the ridiculous modern synthesis (haha) of the establishment clause. I copied both my senators and representative in the house.

Semper Fi.



#22058: — 04/15  at  11:04 AM
"Isn't it cool where a little evidence and logic will take you?"

Yes, my sentiments exactly. I had a similar thought one day while observing a parhelion, or sundog (see a neat picture at http://www.sundog.clara.co.uk/atoptics/phenom.htm). Just by observing this particular atmospheric phenomenon, I knew that the thin clouds at a great distance were composed of ice crystals that were shaped like plates rather than columns. Then I thought, "How neat that I can look from so far away at something like this and know what it is and what causes it."



#22067: — 04/15  at  11:36 AM
Jeremy,
I don't know anything about ovirators, but with ducks and chickens it works like this. The bird will usually lay an egg a day until the nest gets up to a dozen or even two dozen. Those eggs don't do anything at all until the hen starts "Setting" (that's what we called it in the country). You can't candle them to see if they are doing anything, because they aren't. Then the hen will start really start setting on them all day every day. About a month later all of the eggs will hatch within about an hour of each other even though they were layed as much as a month apart. The really cool part of the system is that none of them really starts developing until incubation starts from the hen "Setting". Don't know if this is right for oviraptors, but it is certainly right for ducks and chickens.
Ron



#22070: coturnix — 04/15  at  11:51 AM
True of quails, too.

In a farm (or a lab) setting you can keep eggs in the fridge for up to two weeks and then "set" them in the incubator all at the same time - this is just imitating what the hen is naturally doing.

A clutch of a domesticated chicken or qual can have many eggs, but their wild counterparts still lay only 4-10 depending on species, age of the bird and latitude (photoperiod).



#22071: — 04/15  at  11:53 AM
All this says to me is that them bones were used for Easter Egg hunts by our ancestors just a few thousand years back (like the goodold book says)!
I am not kidding just trying to think like a creationist for a week-you know that old saying about walking in someone else's shoes for a mile? wink



#22093: — 04/15  at  01:54 PM
This stuff is so totally hip. Awesome.

Um. You might need to walk a marathon in those shoes before your synapses start firing as irregularly as a creationist's.



#22109: judgeMC — 04/15  at  08:00 PM
How large are the eggs the oviraptor layed?



's avatar #22112: — 04/15  at  10:33 PM
In oviraptor nests, the eggs are all in circular rings, with the pointed end outward. From this we can infer that the mother oviraptor stood in the center of the nest when laying the eggs. If oviraptors were like birds, the inference is weak. Birds are always turning and moving and arranging the eggs in the nest. There may be a better reason for this strange pattern.

Quod natura non sunt turpia



#22119: — 04/16  at  06:34 AM
If oviraptors were like birds, the inference is weak. Birds are always turning and moving and arranging the eggs in the nest. There may be a better reason for this strange pattern.

We have good nests from another theropod dinosaur called Troodon, its related to oviraptorids but much closer to birds. We see the same nest pattern in Troodon as with oviraptors so it seems likely then, that although these dinos were extreamly birdy in most aspects of their physiology, their eggs did not have chazale(sp?) and thus were not turned.



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