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Post by Ajax on Dec 19, 2008 4:26:31 GMT
the eggs December 19, 2008, 10:34 am WASHINGTON (Reuters) - You can call it dino daddy day-care.
Scientists who examined the fossilized remains of three types of medium-sized dinosaurs found with large clutches of eggs have concluded that the males rather than the females seem to have guarded the nests and brooded the eggs.
Writing on Thursday in the journal Science, they said this behavior is seen in certain existing species of birds. Scientists believe birds evolved from small, feathered predatory dinosaurs more than 150 million years ago.
The three types of dinosaurs, Troodon, Oviraptor and Citipati, lived roughly 75 million years ago and were theropods -- the primarily meat-eating group that also includes monstrous beasts like Tyrannosaurus rex and Giganotosaurus.
"There are a lot of characteristics that we once thought were unique to birds that are turning out not to be -- that they first arose in their theropod ancestors," Montana State University paleontologist Frankie Jackson, one of the researchers, said in a telephone interview.
The scientists said the findings suggest that at least in these types of dinosaurs, the males may have mated with several females that laid eggs in one large clutch. When the females left, the males incubated and protected the eggs on their own.
PATERNAL CARE
Male-only care for eggs occurs among certain large flightless birds like emus and rheas and the South American tinamous, according to fellow Montana State University paleontologist David Varricchio.
In these cases, the dinosaurs were found with an unusually large number of eggs -- each nest containing from 22 to 30 eggs. They were found in Montana in the case of Troodon, and Mongolia in the case of Oviraptor and Citipati.
After a close examination of the fossils, the scientists concluded that the dinosaurs were males.
Florida State University paleobiologist Greg Erickson said there was no evidence of medullary bone -- the extra bone that breeding female birds and dinosaurs use to make eggs -- or evidence of another process by which female reptiles such as crocodiles acquire mineral salts to make eggs.
Males contribute to parental care in less than 5 percent of mammal and reptile species. Males and females contribute to parental care together in more than 90 percent of birds.
Among a group called Paleognathes -- an ancient lineage that branched off soon after birds evolved from dinosaurs and includes ostriches, emus and tinamous -- paternal care and polygamy are the rule, the scientists said.
The scientists are uncertain why these dinosaurs died suddenly while perching over the eggs. In the Mongolian ones, they may have perished in sandstorms or collapsing sand dunes.
(Editing by Julie Steenhuysen and Sandra Maler)
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Post by stoneage on Dec 19, 2008 5:10:03 GMT
the eggs December 19, 2008, 10:34 am WASHINGTON (Reuters) - You can call it dino daddy day-care. Scientists who examined the fossilized remains of three types of medium-sized dinosaurs found with large clutches of eggs have concluded that the males rather than the females seem to have guarded the nests and brooded the eggs. Writing on Thursday in the journal Science, they said this behavior is seen in certain existing species of birds. Scientists believe birds evolved from small, feathered predatory dinosaurs more than 150 million years ago. The three types of dinosaurs, Troodon, Oviraptor and Citipati, lived roughly 75 million years ago and were theropods -- the primarily meat-eating group that also includes monstrous beasts like Tyrannosaurus rex and Giganotosaurus. "There are a lot of characteristics that we once thought were unique to birds that are turning out not to be -- that they first arose in their theropod ancestors," Montana State University paleontologist Frankie Jackson, one of the researchers, said in a telephone interview. The scientists said the findings suggest that at least in these types of dinosaurs, the males may have mated with several females that laid eggs in one large clutch. When the females left, the males incubated and protected the eggs on their own. PATERNAL CARE Male-only care for eggs occurs among certain large flightless birds like emus and rheas and the South American tinamous, according to fellow Montana State University paleontologist David Varricchio. In these cases, the dinosaurs were found with an unusually large number of eggs -- each nest containing from 22 to 30 eggs. They were found in Montana in the case of Troodon, and Mongolia in the case of Oviraptor and Citipati. After a close examination of the fossils, the scientists concluded that the dinosaurs were males. Florida State University paleobiologist Greg Erickson said there was no evidence of medullary bone -- the extra bone that breeding female birds and dinosaurs use to make eggs -- or evidence of another process by which female reptiles such as crocodiles acquire mineral salts to make eggs. Males contribute to parental care in less than 5 percent of mammal and reptile species. Males and females contribute to parental care together in more than 90 percent of birds. Among a group called Paleognathes -- an ancient lineage that branched off soon after birds evolved from dinosaurs and includes ostriches, emus and tinamous -- paternal care and polygamy are the rule, the scientists said. The scientists are uncertain why these dinosaurs died suddenly while perching over the eggs. In the Mongolian ones, they may have perished in sandstorms or collapsing sand dunes. (Editing by Julie Steenhuysen and Sandra Maler) More then likely the reason they were perching over the nest is they were eating the eggs!
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Post by crazycrowman on Dec 19, 2008 14:25:55 GMT
"More then likely the reason they were perching over the nest is they were eating the eggs!" Highly unlikely. If it was dad doing all of the sitting, that would be just like modern Emus!....though, all of Paleognathes do have some kind of shared parental duties...
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Post by [][][]cordylus[][][] on Dec 19, 2008 15:07:16 GMT
Interesting.
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Post by Tyrannax on Dec 19, 2008 17:05:34 GMT
Nothing better then having a 7 ton Male Tyrannosaurus protecting you. Sounds safe.
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Post by Tyrannax on Dec 19, 2008 17:25:42 GMT
Or maybe it was the other way around? OR maybe there was no weight difference? OR maybe Tyrannosaurus weighed even more? ;D
Why did I answer a question with another question? ;D
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Post by [][][]cordylus[][][] on Dec 19, 2008 17:36:24 GMT
Well, there are some trex's that have that special egg-laying bone, and those are considerably larger than other trexs, so...
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Post by Tyrannax on Dec 19, 2008 18:17:51 GMT
The special egg laying bone? lol. I guess that sums things up, huh CT? ;D ;D ;D
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Post by sid on Dec 19, 2008 18:21:06 GMT
Dinosaurs are even more awesome...And now,how can anyone still consider 'em "dumb beasts",eh? ;D
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Post by [][][]cordylus[][][] on Dec 19, 2008 19:49:36 GMT
That was back in the day when they were lumbering, sprawling lizards. ;D
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Post by Tyrannax on Dec 19, 2008 19:52:20 GMT
Ahhh....when fierce Brontosaurs bit the necks of Allosaurs as they were threatened by a deadly fall. ;D
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Post by crazycrowman on Dec 19, 2008 21:14:56 GMT
"The special egg laying bone? lol. I guess that sums things up, huh CT?" dinosaurs.about.com/od/dailylifeofadinosaur/a/dinosexing.htmWell, the "type of bone" aside, one can look at modern egg layers. In birds, who generally lay large eggs, the females are often bigger in size then the males to carry the eggs, AND in many of them they are significantly larger so that they do not directly compete with their mate for food. (males hunt smaller prey then do the females, in birds like Red Tails, Falcons, and Eagles, and are usually more agile, allowing them to take things on the wing that females can not - females can tackle prey MUCH large then males ever could) judson.blogs.nytimes.com/2008/02/12/a-tyrannical-romance/Male animals that fight over turf in ritualized battles are often larger then the females they live alongside. Crocs, many lizard species, many kinds of Tortoises (though, in general, female turtles are much larger then males) Big cats, Ungulates.... Its not A bone, BTW, if they are talking about "medullary bone", its a type of calcium deposit that only female birds have. This has also been contested. www.redorbit.com/news/health/154084/t_rex_sexing_is_it_a_he_or_she/I take it with a few grains of salt until more study has been done. My main question to the above findings would be have they found medullary bone in oviraptors, and in the case of the one found with eggs, has it been found in that specimen ? If so, (it being seen in what is most definitely a female, and was not seen in all specimens) it would really back the likely hood that is could be used as a tool in sexing dinosaurs who are in the nesting cycle with a greater degree of certainty. findarticles.com/p/articles/mi_m1511/is_/ai_14966971If are talking about ONE bone, it would be in looking at the structure and shape of the chevron bones near the pelvis to see if there was anywhere for the attachment of muscles relating to the male copulatory organ that is present in crocodilians - Quite a few studies indicate this method of "sexing" is invalid. www.ncbi.nlm.nih.gov/pubmed/16351976?dopt=AbstractI think it was the book "Rex Appeal" that covered the above hypothesis in more detail. That or "Tyrannosaurus Sue". I am sure most nest predators would have passed on having to deal with ANY Tyrannosaurus, and I have a feeling T rexes did not sit on a nest. (sitting a nest would make sense if you are fluffy and can spread out across it without actually sitting upon your eggs or chicks) I would personally assume they nested more like how crocodilians or megapode birds do until we learn more about them.
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Post by crazycrowman on Dec 19, 2008 21:38:47 GMT
Ahhh....when fierce Brontosaurs bit the necks of Allosaurs as they were threatened by a deadly fall. ;D Those sauropods didn't stand a chance against those viscous theropods ;D
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Post by [][][]cordylus[][][] on Dec 19, 2008 22:00:47 GMT
^ I see he has been chewing on your poor invicta brachio.
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Post by crazycrowman on Dec 19, 2008 22:26:28 GMT
^ I see he has been chewing on your poor invicta brachio. Nope. It is chewed though, good spotting. I think that is either dog or child damage. It was a mart purchase. The mart/ebay lot invicta and marx figures seem to have a fair bit of "chew wear" sometimes. I do NOT allow my feathered beasties a chance to chew ANY of my figures. (I am sure some of them would delight in it though - they are actually not housed in the main part of the house, but rather in a modified greenhouse areas/Florida rooms attached to the house) She along with the other birds has proper parrot toys and baby toys for chewing purposes. The only bird that lives IN my house is one that can not chew -Matilda the Kookaburra, and she is in a large indoor flight. Here Chainsaw is making eye contact with the new Papo schleich Spino - I think she is trying to intimidate it. She is true to her name so I am careful with how long I leave her near anything.
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Post by Tyrannax on Dec 19, 2008 23:11:01 GMT
He's a vicious beast!! Nah...cute bird.
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Post by [][][]cordylus[][][] on Dec 19, 2008 23:13:31 GMT
that isn't the papo spino...
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Post by crazycrowman on Dec 19, 2008 23:34:05 GMT
*slaps self in face* ! DUHHHHhhhhhhhhhhhhhhhh yeah. its not. My bad. They are both figures from that side of the pond though I think all of the new Schleich figures are pretty snazzy. On an almost thread related note, does anyone know if any spinosauridae nests/eggs/juveniles have ever been found ?
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Post by [][][]cordylus[][][] on Dec 20, 2008 1:36:15 GMT
^ Heh! Those will never be found, as if morocco doesn't want any paleontologists coming in to get spino skulls (They prefer to hack out the teeth and sell them on places like ebay), so I doubt anybody would find any spino eggs. Same thing goes for juveniles. IF there were any bones to be found, moroccans wouldn't want them to be found, or maybe they'd just hack out a few bones to sell on ebay. And, spinosaurus was a relatively delicate animal as an adult, imagine how fragile juvi bones would be.... I'd imagine that spinosaurus nests' were made out of soft mud and swamp plants, both of which would be hard to preserve in the swampy environment. But man, that would be an awesome discovery... .
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Post by crazycrowman on Dec 20, 2008 1:55:26 GMT
^ Heh! Those will never be found, as if morocco doesn't want any paleontologists coming in to get spino skulls (They prefer to hack out the teeth and sell them on places like ebay), so I doubt anybody would find any spino eggs. Same thing goes for juveniles. IF there were any bones to be found, moroccans wouldn't want them to be found, or maybe they'd just hack out a few bones to sell on ebay. And, spinosaurus was a relatively delicate animal as an adult, imagine how fragile juvi bones would be.... I'd imagine that spinosaurus nests' were made out of soft mud and swamp plants, both of which would be hard to preserve in the swampy environment. But man, that would be an awesome discovery... . That is in part why I said spinosauridae. I know we have scrappy remains of Spinosaurus at best, let alone anything more. As far as the moroccans pulling teeth out of skulls and not wanting specimens to be found, I think those are some rather outrageous claims. While I know they have an open and steady market in fossils, and some major heat between scientists/fossil dealers, theropod teeth are not that uncommon in the world of fossils. If the major large scale commercial fossil dealers that are over there DID find a skull, I am fairly sure that would end up on the market (legal or not) as one piece, (or several) not have be destoryed or have the teeth pulled from it.
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