Parasaurolophus horn function

[Dinoguy2]

Not sure what the current consensus is on para crests. But, at one time, wasn't one species, P. cyrtocristatus, thought to have been a female of P. walkeri?



I'm not sure that opinion is valid any more, though.

Not valid. The two crest types are definitely different species, they're not even from the same time and place. Long crest is from a be lower Dino park formation of Alberta only. Short crest is from 3 million years later in the Kirtland formation of New Mexico. The two crest types are never found in the same formation. If they ever are this hypothesis needs to be revised, but we know from other hadrosaurs that crest shape varied a lot between species and over time.

Basically, this theory came from a time before stratigraphy was well understood as it is now. It would be like saying Daspletosaurus is a female T. rex!

[HD-man]

Not valid.

Being controversial doesn't necessarily invalidate something as a possibility. We'll probably have to agree to disagree. I'm just saying that at least some experts consider it a valid possibility (which is good enough for me). Besides Gardom/Milner & Holtz (See my previous posts), there's Benton (See Figure 8.18: http://books.google.com/books?id=oBgbBAAAQBAJ&pg=PA230&dq=female+parasaurolophus&hl=en&sa=X&ei=9-smVI_yJYOeyQSMxoKIAw&ved=0CB0Q6AEwAA#v=onepage&q=female%20parasaurolophus&f=false ) & Cowen (See Figure 12.35: http://books.google.com/books?id=RFRMFrRZo3kC&pg=PA159&dq=female+parasaurolophus&hl=en&sa=X&ei=A-wmVOK1K5ClyAT8uYHYAQ&ved=0CCIQ6AEwATgK#v=onepage&q=female%20parasaurolophus&f=false ) off the top of my head.

[stargatedalek]

I just don't buy it, the location and the time difference are more than enough for me, plus the differences in the skeleton just don't add up

it does however point towards the possibility that these are male and female from two separate species, and that gender dimorphism could be possible

[Dinoguy2]

Not valid.

Being controversial doesn't necessarily invalidate something as a possibility. We'll probably have to agree to disagree. I'm just saying that at least some experts consider it a valid possibility (which is good enough for me). Besides Gardom/Milner & Holtz (See my previous posts), there's Benton (See Figure 8.18: http://books.google.com/books?id=oBgbBAAAQBAJ&pg=PA230&dq=female+parasaurolophus&hl=en&sa=X&ei=9-smVI_yJYOeyQSMxoKIAw&ved=0CB0Q6AEwAA#v=onepage&q=female%20parasaurolophus&f=false ) & Cowen (See Figure 12.35: http://books.google.com/books?id=RFRMFrRZo3kC&pg=PA159&dq=female+parasaurolophus&hl=en&sa=X&ei=A-wmVOK1K5ClyAT8uYHYAQ&ved=0CCIQ6AEwATgK#v=onepage&q=female%20parasaurolophus&f=false ) off the top of my head.

Both of those sources are review books summarizing previous research, not scientific arguments for or against the hypothesis. I'd be swayed by an actual research paper on this particular topic.

For example, it would be nice if any of the sources you listed wrote what study they're basing that opinion on. Are they all referring to the same 35 year old study from the 1970s? Sometimes a meme like this can carry on for ages before anybody bothers to do follow up studies looking at it critically.

[Gryphoceratops]

Ofcourse there are always some expections. For mammals it would be the Spotted Hyena, where the female is bigger than the male.

There are actually a lot of animal species that are female larger.  Male larger sexual size dimorphism isn't really considered the norm.  You can find many examples of both male and female larger species in every animal class.  I did my undergraduate labwork on sexual size dimorphism with reptiles actually.  In some reptiles (including birds) the presence of testosterone actually inhibits growth.  It varies highly depending on the exact species.

To answer Amargasaurus' question, when it comes to display adaptations (crests, sails, dewlaps, colors...) when dealing with reptiles (including birds) the vast majority of species where these adaptations are present, they are present or more elaborate in the males.  Yes, there a few bird species where the female is brighter but this is not typical at all.  When dealing with extinct dinosaurs it is safe to assume, until data suggests otherwise, that the bigger crest = male.

As far as the species difference between long and short crested parasaurolophus- Dinoguy is correct.  The long and short crested specimens are from millions of years apart in different parts of the world.  They are definitely different species.  That being said, there isn't really a wide enough pool of individual parasaurolophus skulls from either species to come to a strong conclusion if males and females had different crests.  However, if we look at lambeosaurine species that we do have a big enough pool of specimens to go from (Hypacrosaurus comes to mind off the top of my head) we find that males (or what we assume are males) tend to have more elaborate crests than females.  It wouldn't be unreasonable to assume that males and females of either species of parasaurolophus had different sized crests though.  A female P. walkeri very well may have looked similar to a P. cyrtocristatus anyway.  It just hasn't been found. 

[Brachiosaurus]

I remember seeing a documentary that suggested that parasaurophus might have been able to use its calls as a defense if a few gathered together and shouted at a predator making such a loud sound it would scramble the predator's brain and disorient them.

[Gryphoceratops]

I remember seeing a documentary that suggested that parasaurophus might have been able to use its calls as a defense if a few gathered together and shouted at a predator making such a loud sound it would scramble the predator's brain and disorient them.

That is from the Discovery Channel miniseries called Clash of the Dinosaurs.  It was notorious for taking at least one paleontologist grossly out of context in addition to oversensationalizing the dinosaurs.  That being said there is no real scientific proof that a group of parasaurolophus would cause another animal brain damage with their sounds as Dr. Bakker appears to have suggested.

[Brachiosaurus]

I remember seeing a documentary that suggested that parasaurophus might have been able to use its calls as a defense if a few gathered together and shouted at a predator making such a loud sound it would scramble the predator's brain and disorient them.

That is from the Discovery Channel miniseries called Clash of the Dinosaurs.  It was notorious for taking at least one paleontologist grossly out of context in addition to oversensationalizing the dinosaurs.  That being said there is no real scientific proof that a group of parasaurolophus would cause another animal brain damage with their sounds as Dr. Bakker appears to have suggested.

I remember clash of the dinosaurs, it made me made because it was saying sauropods were so dumb they couldn't identify what a predator was 

[HD-man]

For example, it would be nice if any of the sources you listed wrote what study they're basing that opinion on. Are they all referring to the same 35 year old study from the 1970s?

Benton cited Hopson & Cowen cited Olsen, who cited Norman (See "Parasaurolophus" under "Ornithischians of the Judith River beds": http://eesc.columbia.edu/courses/v1001/twomed.html ).

Sometimes a meme like this can carry on for ages before anybody bothers to do follow up studies looking at it critically.

To be fair, as I mentioned in a previous post, Barden cited Hopson in a relatively recent paper ("Sexual dimorphism in dinosaurs: a review of the evidence and approaches"). The Parasaurolophus results may be less convincing on their own, but are stronger when combined w/the results  of other hadrosaurs.

That is from the Discovery Channel miniseries called Clash of the Dinosaurs.  It was notorious for taking at least one paleontologist grossly out of context in addition to oversensationalizing the dinosaurs.  That being said there is no real scientific proof that a group of parasaurolophus would cause another animal brain damage with their sounds as Dr. Bakker appears to have suggested.

To be fair, Bakker didn't say anything about "brain damage" (See the following video at about 29:20).

https://www.youtube.com/watch?v=nv3SVjkfPf0&spfreload=10

[laticauda]

I remember seeing a documentary that suggested that parasaurophus might have been able to use its calls as a defense if a few gathered together and shouted at a predator making such a loud sound it would scramble the predator's brain and disorient them.

Parasaurolophus Psionics.  I like the idea but that is only real in fictional universes.  As for the whose is bigger and what is it used for, all jokes aside, it is unknown.  It is believed in conjunction with physical structural evidence, that the horn was used to make sound.  Weather it was to attract a mate, establish dominance, idle chit-chat, or scare off a predator, it is pure speculation.  If you want some interesting data about the horn growth and possible sounds, check out  baby Dinosaue Joe, one of the most complete Parasaurolophus fossilized skeletons known. 

This could be a good place to look for information:
Ontogeny in the tube-crested dinosaur Parasaurolophus (Hadrosauridae) and heterochrony in hadrosaurids

Andrew A. Farke​1, Derek J. Chok2, Annisa Herrero2, Brandon Scolieri2, Sarah Werning3

OR

An unusual hadrosaurid braincase from the Dinosaur Park Formation and the biostratigraphy of Parasaurolophus (Ornithischia: Lambeosaurinae) from southern Alberta

David C. Evans,a Rebecca Bavington,b Nicolás E. Campione

[Gryphoceratops]

For example, it would be nice if any of the sources you listed wrote what study they're basing that opinion on. Are they all referring to the same 35 year old study from the 1970s?

Benton cited Hopson & Cowen cited Olsen, who cited Norman (See "Parasaurolophus" under "Ornithischians of the Judith River beds": http://eesc.columbia.edu/courses/v1001/twomed.html ).

Sometimes a meme like this can carry on for ages before anybody bothers to do follow up studies looking at it critically.

To be fair, as I mentioned in a previous post, Barden cited Hopson in a relatively recent paper ("Sexual dimorphism in dinosaurs: a review of the evidence and approaches"). The Parasaurolophus results may be less convincing on their own, but are stronger when combined w/the results  of other hadrosaurs.

That is from the Discovery Channel miniseries called Clash of the Dinosaurs.  It was notorious for taking at least one paleontologist grossly out of context in addition to oversensationalizing the dinosaurs.  That being said there is no real scientific proof that a group of parasaurolophus would cause another animal brain damage with their sounds as Dr. Bakker appears to have suggested.

To be fair, Bakker didn't say anything about "brain damage" (See the following video at about 29:20).

https://www.youtube.com/watch?v=nv3SVjkfPf0&spfreload=10

He said the wave of sound from a herd of Parasurolophus could "scramble its brains" and he also said it could knock a predator over.  Watch at 30:30.  His exact wording isn't really the point.  The show was not very good.  It was also notorious for taking at least one paleontologist out of context through editing.

http://svpow.com/2009/12/15/lies-damned-lies-and-clash-of-the-dinosaurs/

I would not use that show as a reference.

[HD-man]

He said the wave of sound from a herd of Parasurolophus could "scramble its brains" and he also said it could knock a predator over.  Watch at 30:30.  His exact wording isn't really the point.  The show was not very good.  It was also notorious for taking at least one paleontologist out of context through editing.

http://svpow.com/2009/12/15/lies-damned-lies-and-clash-of-the-dinosaurs/

I would not use that show as a reference.

1stly, my point is that there's a BIG difference btwn what you said ("cause another animal brain damage") & what Bakker actually said ("discombobulate it, scramble its brains").

2ndly, I know you probably didn't mean to, but please don't put words in my mouth. I never said anything about CofD being good or used as a reference. In fact, I basically said the opposite of that in the "Wierd/Curios Books & Media" thread ( http://dinotoyblog.com/forum/index.php?topic=292.20 ). In this case, I thought I made clear in my previous post that I was only using the CotD video to show what Bakker actually said when I said, "To be fair, Bakker didn't say anything about "brain damage" (See the following video at about 29:20)."

[Gryphoceratops]

He said the wave of sound from a herd of Parasurolophus could "scramble its brains" and he also said it could knock a predator over.  Watch at 30:30.  His exact wording isn't really the point.  The show was not very good.  It was also notorious for taking at least one paleontologist out of context through editing.

http://svpow.com/2009/12/15/lies-damned-lies-and-clash-of-the-dinosaurs/

I would not use that show as a reference.

1stly, my point is that there's a BIG difference btwn what you said ("cause another animal brain damage") & what Bakker actually said ("discombobulate it, scramble its brains").

2ndly, I know you probably didn't mean to, but please don't put words in my mouth. I never said anything about CofD being good or used as a reference. In fact, I basically said the opposite of that in the "Wierd/Curios Books & Media" thread ( http://dinotoyblog.com/forum/index.php?topic=292.20 ). In this case, I thought I made clear in my previous post that I was only using the CotD video to show what Bakker actually said when I said, "To be fair, Bakker didn't say anything about "brain damage" (See the following video at about 29:20)."

I was simply verifying that I meant at the 30:30 mark as oppose to the 29:20 you said (where he says something related, but different, which was not what I was referring to.) The difference between "brain damage"  and the slang expression which Dr. Bakker used could could vary depending on who is watching the program.   Like I said earlier, even if the terminology can be viewed as different things, it is besides my point.   

The rest I meant more generally stated so I'm sorry if you received the impression from me that I was putting words in your mouth.  I didn't assume you were wholeheartedly a fan of Clash of the Dinosaurs.  If you said something about the show on a separate thread that's cool, but but not everyone reads every thread on here.  (I don't!)

[Newt]

As far as I can tell, there are only two ways to definitively ID a female dinosaur: by finding an egg or embryo in situ in an articulated skeleton, or by finding medullary bone, a type of bone secreted inside the long bones of some female ornithodirans as a temporary calcium storage site prior to formation of eggshells. All assertions about gender ID based on size and ornamentation are pure speculation.

Medullary bone has been found in Tyrannosaurus rex, Allosaurus fragilis, and Tenontosaurus tilletti:
http://www.sciencemag.org/content/308/5727/1456.full
http://www.pnas.org/content/105/2/582.full

Associated eggs/embryos have been found for marine reptiles and at least one pterosaur; I can't think of any dinosaur examples that are still considered valid (there is a Ghost Ranch Coelophysis specimen that was variously considered to be pregnant or a cannibal, but the bones inside it were apparently not Coelophysis after all).

As Gryphoceratops pointed out, size dimorphism is not a good indicator. For one thing, small sample sizes, the difficulty of determining somatic maturity in dinosaur specimens, and the confounding effects of environmental and population variation makes it difficult to even detect a pattern of dimorphism in most species. You'd really need a whole lot of specimens from a single population.

But even if you can show there are two size classes of adults in this population, what does that tell you? Are the larger specimens males, females, or some combination of the two? After all, not all dimorphism is sex-based, or at least not entirely sex-based. There could be a variable gene for gigantism or dwarfism in the population. Or there could be an odd growth curve that allowed animals that passed a certain size to have drastically reduced mortality - perhaps by outgrowing the effective predation ability of local predators- resulting in a relatively small number of animals that squeak through and then live and grow for many years more.

Then we come down to ornamentation. For many of the reasons cited for growth, determining that there are two classes of differently-ornamented adults is difficult to do, and once done, difficult to explain. It's true that males of living animals are far more likely to be highly ornamented than females, and there's no particular reason to think that dinosaurs were different. But there are complicating factors: less-ornamented individuals may not all be females. In a number of living species with sexual dimorphism, some males resemble females and use different reproductive strategies from highly-ornamented males; ruff and Lepomis sunfish are two examples.
http://en.wikipedia.org/wiki/Ruff
http://beheco.oxfordjournals.org/content/14/5/634.full

[HD-man]

I was simply verifying that I meant at the 30:30 mark as oppose to the 29:20 you said (where he says something related, but different, which was not what I was referring to.) The difference between "brain damage"  and the slang expression which Dr. Bakker used could could vary depending on who is watching the program.   Like I said earlier, even if the terminology can be viewed as different things, it is besides my point.   

The rest I meant more generally stated so I'm sorry if you received the impression from me that I was putting words in your mouth.  I didn't assume you were wholeheartedly a fan of Clash of the Dinosaurs.  If you said something about the show on a separate thread that's cool, but but not everyone reads every thread on here.  (I don't!)

Many thanks for the clarification. I feel better now.