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Extinct Animal Questions
Topic Started: Nov 26 2013, 10:24 PM (193,382 Views)
Dino Keeper
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The Man Your Man Could Smell Like

What caused the jump from tripod-position theropod reconstructions to actual bipeds?
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Joe99
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Joe99
Jul 25 2015, 10:20 PM
how accurate is the WWD apatosaurs and diplodocus necks and backs
and could t rex inner mouth look like this
http://images.nationalgeographic.com/wpf/media-live/photos/000/896/overrides/adelie-penguin-antarctica_89655_990x742.jpg
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Posted Image Flish
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For your first question, the WWD Diplodocids were accurate for the time, but a few years after WWD was made, it became apparent they likely did hold their necks up at an angle. If it wasn't for all the muscles and ligaments used to do that, the back would probably be accurate, but because they held their neck up, they probably didn't have a back that sloped down like that.

As for a Tyrannosaurus's mouth, it's possible, but I really doubt Tyrannosaurus is eating krill so I'd have to say it's very unlikely.
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Joe99
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Flish
Jul 26 2015, 01:36 AM
For your first question, the WWD Diplodocids were accurate for the time, but a few years after WWD was made, it became apparent they likely did hold their necks up at an angle. If it wasn't for all the muscles and ligaments used to do that, the back would probably be accurate, but because they held their neck up, they probably didn't have a back that sloped down like that.

As for a Tyrannosaurus's mouth, it's possible, but I really doubt Tyrannosaurus is eating krill so I'd have to say it's very unlikely.
thanks and for the rex maybe a toothed tounge and mouth with teeth designed to help with eating teeth and bones
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Posted Image Guat
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Joe99
Jul 26 2015, 01:39 AM
Flish
Jul 26 2015, 01:36 AM
For your first question, the WWD Diplodocids were accurate for the time, but a few years after WWD was made, it became apparent they likely did hold their necks up at an angle. If it wasn't for all the muscles and ligaments used to do that, the back would probably be accurate, but because they held their neck up, they probably didn't have a back that sloped down like that.

As for a Tyrannosaurus's mouth, it's possible, but I really doubt Tyrannosaurus is eating krill so I'd have to say it's very unlikely.
thanks and for the rex maybe a toothed tounge and mouth with teeth designed to help with eating teeth and bones
Why would Rex eat teeth? Or even need a toothed tongue? Crocodiles eat bones yet they don't have teeth on their tongue and the same for their mouth insides, crocodiles do have teeth but they are not in the same areas as goose or penguin "teeth".
Crocodiles Mouths
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Joe99
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Humuhumunukunukuāpuaa
Jul 26 2015, 01:47 AM
Joe99
Jul 26 2015, 01:39 AM
Flish
Jul 26 2015, 01:36 AM
For your first question, the WWD Diplodocids were accurate for the time, but a few years after WWD was made, it became apparent they likely did hold their necks up at an angle. If it wasn't for all the muscles and ligaments used to do that, the back would probably be accurate, but because they held their neck up, they probably didn't have a back that sloped down like that.

As for a Tyrannosaurus's mouth, it's possible, but I really doubt Tyrannosaurus is eating krill so I'd have to say it's very unlikely.
thanks and for the rex maybe a toothed tounge and mouth with teeth designed to help with eating teeth and bones
Why would Rex eat teeth? Or even need a toothed tongue? Crocodiles eat bones yet they don't have teeth on their tongue and the same for their mouth insides, crocodiles do have teeth but they are not in the same areas as goose or penguin "teeth".
Crocodiles Mouths
fair enough this question is for a story im writing
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DinoBear
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OK so some websites (usually of crappy quality) propose a weight of ~4 tons for a 12 meter long Edmontosaurus. This seems to be pretty wrong but I'm curious: how much would a large Edmonto weigh?

Futzing around with Scott Hartman's skeletals seems to show that his Edmontosaurus has a longer and possibly deeper torso than a similarly sized T. rex, but given that I have no experience with scaling things I probably got something way off
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Luca9108
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Master of Dinosaurs

Was it possible for Postosuchus to run bipedal?
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babehunter1324
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While Edmotosaurus may have had a deeper chest cavity than Tyrannosaurus it likely was a lot narrower from frontal view.

Not sure if any volumetric study (which sometimes result in a heavier or lighter weight than the measuring femur and humerus measure systems) has been performed on any Hadrosaurid...
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BossMan, Jake
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Son of God

So as we know there are a few scattered fossils that could point to sauropods potentially larger than previous record holders. But are there any isolated theropod fossils that are bigger than either spinosaurus or giganotosaurus?
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Furka
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Got a couple of question regarding Tylosaurus:

- do we have an idea of the growth rate of said animal (or other mosasaurs for the matter) ?

- how would its bite work ? Was it capable of feeding on large animals, or it was more adapted to smaller preys that it could eat whole ?
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DinoBear
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BossMan, Jake
Jul 29 2015, 02:02 PM
So as we know there are a few scattered fossils that could point to sauropods potentially larger than previous record holders. But are there any isolated theropod fossils that are bigger than either spinosaurus or giganotosaurus?
IIRC one of the Mapusaurus fossils indicates a giant individual, but being fragmentary it remains to be seen if it is the largest known theropod. In general though, all of the following probably got to pretty much the same weight (~8 tons).

- Tyrannotitan (pretty dubious but IIRC the second one is like 7.5 tons)
- Spinosaurus (depends on the weight, but in any case is the longest)
- Carcharodontosaurus
- Giganotosaurus
- Mapusaurus
- T. rex (shortest in length of the group, easily the one with the largest sample size)
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Zoo Tycooner FR
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#Lithopédion

Furka : I suggest you this article : http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0076741 ;)
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Incinerox
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Āeksiot Zaldrīzoti

DinoBear
Jul 29 2015, 03:02 PM
BossMan, Jake
Jul 29 2015, 02:02 PM
So as we know there are a few scattered fossils that could point to sauropods potentially larger than previous record holders. But are there any isolated theropod fossils that are bigger than either spinosaurus or giganotosaurus?
IIRC one of the Mapusaurus fossils indicates a giant individual, but being fragmentary it remains to be seen if it is the largest known theropod. In general though, all of the following probably got to pretty much the same weight (~8 tons).

- Tyrannotitan (pretty dubious but IIRC the second one is like 7.5 tons)
- Spinosaurus (depends on the weight, but in any case is the longest)
- Carcharodontosaurus
- Giganotosaurus
- Mapusaurus
- T. rex (shortest in length of the group, easily the one with the largest sample size)
There's a few things to bear in mind about this actually.

1) There seems to be an obvious cap on how large terrestrial theropods could actually get (somewhere in the mid-40ft range). It's highly likely all the theropods listed could be classified as "the same length". I'm not saying weight just because that point comes later.

2) Obviously, using only fragments to estimate overall size is gonna distort any results depending on how you fill in the blanks. And you'd be surprised by how much you can mess up the results this way. For instance, Tyrannotitan's barely known from anything. All of its bones are partials, and those officially described were simply noted in some four page description. Current estimates are based on comparisons with Giganotosaurus suggest a 40ft animal. But of course that depends entirely on it being built the same way. In the case of Mapusaurus, you've got a femur that suggests a current maximum of, again, 40 feet. But the same specimen has a pubic shaft a whole 10% LARGER than Giganotosaurus's largest known pubic bone. Even Giganotosaurus itself had problems where its entire skull had to be redesigned a few years ago because the replicas and diagrams used in comparative data was based on an entirely bogus design (basically, the snout was too long and the rear of the skull was VASTLY oversized - This is wrong). And that can completely mess up how you interpret skull : body size ratios in carnosaurs.

2.5) This is more of an add on to the second point, but so far this has only covered some carnosaurs with very small sample sizes. The only giant theropod we have from good data is T. rex, and one of the things that strikes me was how insanely variable that one species was. We have specimens overly robust, specimens with disproportionately sized heads, specimens with massive overbites, you get the idea. These aren't animals that all look the same, no animal is. Every individual's got different proportions. There's this one toe bone attributed to T. rex (I forget the name of the specimen). Anyone that tries to restore that whole specimen based on just a toe bone is going to have a bad time. Which individual is your "average joe" T. rex? Sue's our most complete and has plenty to work with, but is also our oldest and most robust. AMNH 5027 is probably the most reasonably proportioned, but we have no material for its legs, so that individual may have had porportionally massive feet or tiny feet by the species' standards. We just don't know. So apply that logic to the Giganotosaurus dentary that apparently suggests a GIANT Giganotosaurus. Is it really gigantic? Or is it the Giganotosaurus equivalent to T.rex's Stan?

3) Again, we seem to have consistently gigantic carcharodontosaurids reaching more or less 12.2m, with one possible Giga stretching a whole metre longer, but see point 2.5). But so far I've been talking length. Nobody cares about an animal's width when talking about theropod size. In this aspect, Sue would be our heaviest terrestrial theropod by a considerable margin, simply by being super wide compared to any of its equally long carnosaurian rivals. If we go by those numbers, it takes the largest fragmentary Giga specimen to rival Sue, assuming standard proportions. And they'd come out at the same weight (give or take 200kg). But again, this coincides with point 2) in that most of our giant theropods are too fragmentary to make decent weight calculations for on the basis that we have to standardise their build, when clearly (in Mapusaurus's case for instance), you've got an animal with a proportionally deeper body, but proportionally slender legs that max out on a lighter load (I'm seeing 3 tons for the 10m-ish holotype, and I have no idea how reasonable that is because there's no substantial data to work with).

So my thinking is that all giant theropods could probaby hit the same maximum, and that their bodies would have the capacity to be as large as neccesary as long as they don't cross some sort of threshold (I'm assuming the absolute maximum for a carnivorous theropod is 9 tons). It's bogus speculation at that point but there is a running trend of some kind.

Also, pay special note to how I've deliberately ignored Spinosaurus. Spinosaurus is a bizarre and unusual case and we still haven't solved how it supported itself on land at all, numbers aside. And whatever it did, it was the only theropod in that weight class with near-solid bones and a habit of spending a lot of time in water, which would probably increase its potential weight limit significantly. It's so different from the other theropods in every possible way that it makes it impossible to compare. It's completely void in this argument.
Edited by Incinerox, Jul 30 2015, 02:11 AM.
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Even
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@Luca9108: Postosuchus is now considered to be, at least, facultatively bipedal... But see here
Edited by Even, Jul 30 2015, 12:49 PM.
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