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Re: Torosaurus = Triceratops? « Reply #80 on Oct 27, 2009, 2:46pm »
I think we need to see a cronological study of the heads of these ceratopsians. Male, Female from birth to adult. Are there any modern animals that have such a vast array of different head display changes. Not just differences in the sexes but such drastic changes in head gear as the animal ages.
Kuni, we really need to see the skulls of those animals, to show that the sexual dimorphism isn't just external...not that I don't believe you, but I know nothing about lizards.
Oh and Jeb, I think the "Giraffatitan" study made a pretty good case. And Dr Darren Naish agrees, so I'll hide behind him. He has an academic title
I'll have to agree with the results of Brachiosaurus study too actually.The names of the dinosaurs don't mean that much to me,since none of them had names when they were alive anyway.
Oh, and JEB4, there can be huge morphological differences between males and females in vertebrates. Just because two creatures aren't identical doesn't meant they can't be the same species. This is especially true when the traits they differ in are display traits, which often differ between males and females. My dwarf puffers even have this - the males have little inflatable "combs" that they can use to make themselves look bigger, and the females don't have that at all.
I never said animals had to be identical to be members of the same species,what I said was that no horned animal today is known to go through such drastic changes as would be required for Torosaurus to be the late growth stage of the male Triceratops.Besides,the differences between the male and female chemeleons you show are still not as drastic as those between Torosaurus and Triceratops,so what I said about horned animals still stands.(Male chemeleons get bigger horns and display features as they get older,not a complete skull reconfiguration.) I should point out that my reaction to this idea is not from an emotional investment in the image of Triceratops,but from my having noticed too many holes in the theory for it to stand up to scrutiny.
« Last Edit: Oct 27, 2009, 6:03pm by john2xtheman »
Are there any modern animals that have such a vast array of different head display changes. Not just differences in the sexes but such drastic changes in head gear as the animal ages.
Did you even look at those chameleon pictures? The male/female differences are surprisingly similar to a Toro/Tri comparison. And yes, male chameleon crests get bigger over time if the male has good genes.
[ I never said animals had to be identical to be members of the same species,what I said was that no horned animal today is known to go through such drastic changes as would be required for Torosaurus to be the late growth stage of the male Triceratops.Besides,the differences between the male and female chemeleons you show are still not as drastic as those between Torosaurus and Triceratops,so what I said about horned animals still stands.(Male chemeleons get bigger horns and display features as they get older,not a complete skull reconfiguration.) I should point out that my reaction to this idea is not from an emotional investment in the image of Triceratops,but from my having noticed too many holes in the theory for it to stand up to scrutiny.
"Not as drastic"? A male Jackson's has horns, the female has nothing. The male veiled has a head shield twice as tall as a female, and yes, the increase in the size of the head shield will stress other bones in the skull and produce correlated changes in those as well. As long as the "skull reconfiguration" involves strengthening and adding layers of bone (we know this is the case from the meeting report already), it's hardly farfetched. Perhaps you can elaborate more on the issues you have with it.
[ I never said animals had to be identical to be members of the same species,what I said was that no horned animal today is known to go through such drastic changes as would be required for Torosaurus to be the late growth stage of the male Triceratops.Besides,the differences between the male and female chemeleons you show are still not as drastic as those between Torosaurus and Triceratops,so what I said about horned animals still stands.(Male chemeleons get bigger horns and display features as they get older,not a complete skull reconfiguration.) I should point out that my reaction to this idea is not from an emotional investment in the image of Triceratops,but from my having noticed too many holes in the theory for it to stand up to scrutiny.
"Not as drastic"? A male Jackson's has horns, the female has nothing. The male veiled has a head shield twice as tall as a female, and yes, the increase in the size of the head shield will stress other bones in the skull and produce correlated changes in those as well. As long as the "skull reconfiguration" involves strengthening and adding layers of bone (we know this is the case from the meeting report already), it's hardly farfetched. Perhaps you can elaborate more on the issues you have with it.
EDITING MY OWN ERRORS AS I FIND THEM:I would expect the frill to get thicker as it got longer,but it is actually thinner in Torosaurus than in Triceratops,not to mention the epoccipitals,which are not only shaped differently,but smaller than on Triceratops.And there is still the problem with the openings in the frill that are supposedly redeveloped in the frill only in the male.I just find it to be too much of a stretch to be believable.If the differences between the two were just differences in horn and frill size,(and associated strenghthening of bone to accommodate this like in those chemeleons you showed) then I could see it.
« Last Edit: Oct 27, 2009, 7:32pm by john2xtheman »
Re: Torosaurus = Triceratops? « Reply #86 on Oct 27, 2009, 7:31pm »
Guess you'll have to wait for the paper, but realize that from a developmental perspective, there's nothing ridiculous or a "stretch" about it. If you want to check out ridiculous juvenile->adult bone transitions, look at the flatfishes. The skull warps rather dramatically.
Re: Torosaurus = Triceratops? « Reply #87 on Oct 27, 2009, 9:36pm »
Recent studies indicate that Torosaurus is most closely related to Triceratops. Jack Horner has suggested that Torosaurus may in fact represent the adult version of one sex of Triceratops, pointing out that there are no juvenile specimens of Torosaurus and that approximately 50% of all subadult Triceratops skulls have two thin area in ther frill that correspond with the placement of "holes" in Torosaurus skulls. The theory is that all Triceratops had solid frills up to adulthood, but on reaching sexual maturity, one sex or the other would have developed longer frills as a form of display. To counterbalance the extra weight of the elongated frill, holes would have been necessarily developed in the bone. While this theory does explain the absence of any Torosaurus specimens younger then adults and also explains the even split between uniformly thick frills and frills with thin subadult Triceratops specimens, the theory is not yet widely accepted.
Re: Torosaurus = Triceratops? « Reply #88 on Oct 28, 2009, 2:44am »
Indeed. Once the paper is out, we'll see how it goes.
I suspect Tri and Toro are the tip of the iceberg - horns and frills are often display traits, and males usually have different/bigger display traits than females. It may be the case that a lot of ceratopsians and perhaps some hadrosaurs had significant differences between genders.
I'm just showing what in part are Jack Horners thoughts on the subject. My opinion is to wait and see what the scientific community has to say about it, once they have the time to examine and digest his work.
Re: Torosaurus = Triceratops? « Reply #91 on Oct 29, 2009, 2:09pm »
I understood that Toro post-orbital horns were smaller than Trike horns. This shoots a hole in the theory of males having bigger and larger.
From the one paragraph above of stoneage, it seems to be a theory that fits almost all the facts - as stated in that paragraph.
Yet we have a paper by Hunt and Lehmen from 2008 that makes the case for a juvenile Torosaurus. The abstract is unclear about there being a skull. It is unclear about the possibility mentioned by Horner.
This idea put forth by Horner seems unlikely to me, yet it does demand a treatment, simply because it is possible. If it turns out to be true, our entire view and interpretation of the perennial favorite: Triceratops, will really frikkin well shift! When you've got a male whose neck shield can't stand up to the same punishment that the female frill can!.....
At least JPark will have a lucky co-incidence: their dinosaurs are all female!....oooohhhh that makes me feel sick....a hollywood movie that turns out to be on the dot....
« Last Edit: Oct 29, 2009, 2:12pm by fleshanthos »
At least JPark will have a lucky co-incidence: their dinosaurs are all female!....
Life will find a way...
Or in other words, they weren't. Well, they were engineered to be, but then some of them spontaneously changed sex due to their partially amphibian DNA.
Also, ever noticed that the Triceratops in JP has 'fossil' horns? The Papo trike has them too, of course.
Well, they appear all cracked up like the fossilised boney horn cores. If they were covered in keratin horn in life they wouldn't really have looked like that...the Papo trike takes this to a real extreme.
Well, they appear all cracked up like the fossilised boney horn cores. If they were covered in keratin horn in life they wouldn't really have looked like that...the Papo trike takes this to a real extreme.
Oh i see... But even if covered in keratin, they would have looked like that, i think, after many fights and such... I could be wrong, though
At least JPark will have a lucky co-incidence: their dinosaurs are all female!....
Life will find a way...
Or in other words, they weren't. Well, they were engineered to be, but then some of them spontaneously changed sex due to their partially amphibian DNA.
Also, ever noticed that the Triceratops in JP has 'fossil' horns? The Papo trike has them too, of course.
I was thinking the same thing about the trike horns in JP when i recently saw it- they look as cracked as a mounted fossil would look- I doubt horns on a live animal would look so cracked up-
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I think we need to see a cronological study of the heads of these ceratopsians. Male, Female from birth to adult. Are there any modern animals that have such a vast array of different head display changes. Not just differences in the sexes but such drastic changes in head gear as the animal ages. 
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