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Extinct Animal Questions
Topic Started: Nov 26 2013, 10:24 PM (193,451 Views)
SamtheMan
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I'm glad to see that quite a few people are curious about what North America was like at the end of the Cretaceous!

It seems like we can agree that there was still a large seaway that separated the western and eastern parts of North America at the end of the Cretaceous (I didn't even realize that some parts of the Hell Creek Formation were at the very edge of the sea!). However, as Incinerox pointed out, the images we found so far don't do a good job of matching up with dinosaur fossil sites. After some further research, Hell Creek was roughly where Montana, North Dakota, and South Dakota intersect so the western shores of the Western Interior Seaway at that time would have been roughly around the central areas of the Dakotas. It still seems relatively uncertain as to where its eastern shores would've been. I'll keep looking to see if I can find a more accurate picture though this has somewhat inspired me to perhaps make one myself based on what we already know.

@Rhodedicut Thanks for that site about fossils from New Jersey, its appreciated! Apparently most of the fossils from the end of the Cretaceous were from sharks, crocodilians, and other sea life such as mosasaurs and ammonites. It seems like the only dinosaurs that we know fairly well that were in Appalachia at the end of the Cretaceous were the tyrannosaur Dryptosaurus and the large hadrosaur Hypsibema (I thought Hadrosaurus lived with Appalachiasaurus around 78 million years ago but I certainly have no complaints if it actually was contemporary with the Dryptosaurus and Hypsibema). Also, I thought that the extinction event was closer to 66 million years ago but that it also lasted many thousands of years up to 65.5 million years ago since I recall dinosaur fossils being found at that age as well.

@ Dilophoraptor I definitely agree that we need more prehistoric maps (perhaps with locations of major fossil formations as well). If all else fails we could always make them ourselves!
Edited by SamtheMan, Oct 29 2014, 03:07 AM.
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Brach™
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hi

SamtheMan
Oct 29 2014, 03:05 AM
I'm glad to see that quite a few people are curious about what North America was like at the end of the Cretaceous!

It seems like we can agree that there was still a large seaway that separated the western and eastern parts of North America at the end of the Cretaceous (I didn't even realize that some parts of the Hell Creek Formation were at the very edge of the sea!). However, as Incinerox pointed out, the images we found so far don't do a good job of matching up with dinosaur fossil sites. After some further research, Hell Creek was roughly where Montana, North Dakota, and South Dakota intersect so the western shores of the Western Interior Seaway at that time would have been roughly around the central areas of the Dakotas. It still seems relatively uncertain as to where its eastern shores would've been. I'll keep looking to see if I can find a more accurate picture though this has somewhat inspired me to perhaps make one myself based on what we already know.

@Rhodedicut Thanks for that site about fossils from New Jersey, its appreciated! Apparently most of the fossils from the end of the Cretaceous were from sharks, crocodilians, and other sea life such as mosasaurs and ammonites. It seems like the only dinosaurs that we know fairly well that were in Appalachia at the end of the Cretaceous were the tyrannosaur Dryptosaurus and the large hadrosaur Hypsibema (I thought Hadrosaurus lived with Appalachiasaurus around 78 million years ago but I certainly have no complaints if it actually was contemporary with the Dryptosaurus and Hypsibema). Also, I thought that the extinction event was closer to 66 million years ago but that it also lasted many thousands of years up to 65.5 million years ago since I recall dinosaur fossils being found at that age as well.

@ Dilophoraptor I definitely agree that we need more prehistoric maps (perhaps with locations of major fossil formations as well). If all else fails we could always make them ourselves!
iirc the extinction event's lasting effects went into the early Eocene but thats not based on information in front of me right now.
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Luca9108
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Master of Dinosaurs

I have a question: I heard about a dwarf form of Tarascosaurus. Does anyone know the correct name of it?
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Similis
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Tarascosaurus material is scarce as it is (upper thigh bone and supposedly some vertebrae) so I think it's impossible to say whether or not this animal could have 'dwarf forms".
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Luca9108
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Master of Dinosaurs

Thanks for answer :) .
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Brach™
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hi

dwarf Tarascosaurus is from the Dinosaur planet special. It wasn't based on any find, its instead based on insular dwarfism when a population gets isolated on an Island where they then evolve and diverge from the original population like with Sicilian dwarf Elephants and dwarf Mammoths. In this case becoming much smaller than their original counterparts.
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CyborgIguana
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Tarascosaurus is pretty small to begin with anyway.
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Mathius Tyra
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Rat snake is love... Rat snake is life

They are estimated to be only 3-4 metres long...

DP exaggerated its size. It'd be actually only two times bigger than Pyroraptor.
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Incinerox
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Āeksiot Zaldrīzoti

Not only that, it was likely it wasn't even an abelisaur at all.

Also, 3m turns out to be its upper estimate.

The thing, if an abelisaur, was a dwarf in its own right anyway. But I'm leaning towards it not being on at all.

My bets are it was a Noasaurid.
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Even
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Well, we can have a dwarved majungasaurine there (made sense with few-million-years-older Arcovenator found further west)... There's also Betasuchus and such...
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Posted Image Flish
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Incinerox
Oct 31 2014, 07:00 AM
Not only that, it was likely it wasn't even an abelisaur at all.

Also, 3m turns out to be its upper estimate.

The thing, if an abelisaur, was a dwarf in its own right anyway. But I'm leaning towards it not being on at all.

My bets are it was a Noasaurid.
Err... DG, aren't Noasaurids Abelisaurs? :P
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Yi Qi
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Flish
Nov 1 2014, 08:15 PM
Incinerox
Oct 31 2014, 07:00 AM
Not only that, it was likely it wasn't even an abelisaur at all.

Also, 3m turns out to be its upper estimate.

The thing, if an abelisaur, was a dwarf in its own right anyway. But I'm leaning towards it not being on at all.

My bets are it was a Noasaurid.
Err... DG, aren't Noasaurids Abelisaurs? :P
They as a matter of fact are, altough i believe DG was referring to Abelisaurids more specifically.
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Carnoraptorsaur
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Okay I have two questions.

1. I read somewhere that one of the methods we use to tell the age of dinosaurs aka carbon dating is not that accurate. I always thought is was a good method to date fossils but is it accurate or not?

2. I also read that the method we were using to tell the colors of some feathered dinosaurs is not accurate either.
So is it or not?

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CyborgIguana
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1. Carbon dating is only effective on fossils and artifacts less than 60,000 years old. We use other methods for dating things older than that, which are generally believed to be accurate. You didn't happen to get this information off a creationist web-site, did you? :P

2. That's debatable, some believe they are, but others note that the melanosomes may have scattered during the fossilization process, which would mean that the living animals may have been coloured differently.
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Brach™
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hi

Carnoraptorsaur
Nov 1 2014, 10:54 PM
Okay I have two questions.

1. I read somewhere that one of the methods we use to tell the age of dinosaurs aka carbon dating is not that accurate. I always thought is was a good method to date fossils but is it accurate or not?

2. I also read that the method we were using to tell the colors of some feathered dinosaurs is not accurate either.
So is it or not?

https://www.youtube.com/watch?v=QbvMB57evy4

Check this out. The assertion that carbon dating is inaccurate and doesn't work is a watered down fiction by creationists.

You can't carbon date dinosaur fossils because they've been replaced by minerals millions of years ago and thus lacks any carbon to date.
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