Welcome Guest [Log In] [Register]






Shoot a firework rocket ~ Winners!
Make a forum zoo!

Welcome to The Round Table. We hope you enjoy your visit.


You're currently viewing our forum as a guest. This means you are limited to certain areas of the board and there are some features you can't use. If you join our community, you'll be able to access member-only sections, and use many member-only features such as customizing your profile, sending personal messages, and voting in polls. Registration is simple, fast, and completely free.


Join our community!


If you're already a member please log in to your account to access all of our features:

Username:   Password:
Add Reply
Extinct Animal Questions
Topic Started: Nov 26 2013, 10:24 PM (193,452 Views)
stargatedalek
Member Avatar
I'm not slow! That's just my moe!

pre-birds are presumed to have had great colour vision so don't be afraid to make them vibrant, but still try and keep it suited to the animals behavior

IE a large sauropod with few/no predators could be any vibrant colours you wish, but a small ornithopod living amongst dense underbrush would probably need to blend in
Offline Profile Quote Post Goto Top
 
SamtheMan
No Avatar


Hi there everyone.

I've recently become very interested in the geography of North America from the Latest Cretaceous to the Earliest Paleocene (roughly 66 - 65 million years ago) particularly with how the Western Interior Seaway defined the landscape into 3 major landmasses with Laramidia in the west being the most well known and at least a few fossils being known from the east in Appalachia (does anyone know what the 3rd landmass in the north was called and if we have any dinosaur fossils from there?). From what I have gathered so far, Appalachia at the end of the Cretaceous had the three-fingered tyrannosaur Dryptosaurus, the huge hadrosaur Hypsibema, and a few fossils that suggest an unknown species of nodosaur. However, I am still a bit unsure about how long the Western Interior Seaway divided North America or when exactly the Pierre Seaway came into play. Was Appalachia still an island 66-65 million years ago as some sources suggest? Or was it connected to the rest of North America as some other sources suggest? It seems like Laramidia and Appalachia were connected again at the end of the Cretaceous (many more sources plus images make it more likely) but I still encounter some sources that still say Appalachia was an island til the Paleocene so I thought I'd ask for clarification. Also, if it was connected like in this image:

Posted Image

where would the Hell Creek Formation be in relation to the coastline and what would stop the Laramidian animals like Tyrannosaurus and Edmontosaurus from moving into the lands of Appalachian animals like Dryptosaurus and Hypsibema? Thanks in advance.
Offline Profile Quote Post Goto Top
 
Brach™
Member Avatar
hi

SamtheMan
Oct 26 2014, 05:06 PM
Hi there everyone.

I've recently become very interested in the geography of North America from the Latest Cretaceous to the Earliest Paleocene (roughly 66 - 65 million years ago) particularly with how the Western Interior Seaway defined the landscape into 3 major landmasses with Laramidia in the west being the most well known and at least a few fossils being known from the east in Appalachia (does anyone know what the 3rd landmass in the north was called and if we have any dinosaur fossils from there?). From what I have gathered so far, Appalachia at the end of the Cretaceous had the three-fingered tyrannosaur Dryptosaurus, the huge hadrosaur Hypsibema, and a few fossils that suggest an unknown species of nodosaur. However, I am still a bit unsure about how long the Western Interior Seaway divided North America or when exactly the Pierre Seaway came into play. Was Appalachia still an island 66-65 million years ago as some sources suggest? Or was it connected to the rest of North America as some other sources suggest? It seems like Laramidia and Appalachia were connected again at the end of the Cretaceous (many more sources plus images make it more likely) but I still encounter some sources that still say Appalachia was an island til the Paleocene so I thought I'd ask for clarification. Also, if it was connected like in this image:

Posted Image

where would the Hell Creek Formation be in relation to the coastline and what would stop the Laramidian animals like Tyrannosaurus and Edmontosaurus from moving into the lands of Appalachian animals like Dryptosaurus and Hypsibema? Thanks in advance.
Keep in mind the Interior Seaway was much larger than that depicts. Hell Creek is also in a rugged landscape so look around central Montana. When Tyrannosaurus was around the Seaway split in 3 directions toward the Hudson and toward the Yukon.This water was what stood in the way of T.rex and Edmontosaurus showing up in the east.
Offline Profile Quote Post Goto Top
 
CyborgIguana
Member Avatar


IIRC the WIS had receded somewhat by the end of the Cretaceous, but I'm pretty sure it was still big enough to prevent T. rex, Triceratops, Edmontosaurus, Acheroraptor, etc. from spreading to the other side of the continent.
Offline Profile Quote Post Goto Top
 
Brach™
Member Avatar
hi

Yeah the three North American subcontinents likely weren't connected until after the extinction event begun.
Offline Profile Quote Post Goto Top
 
SamtheMan
No Avatar


Just to make things a little more clear, the image I posted was from a source that suggested that it was what North America looked like 65 million years ago, I know the Western Interior Seaway was much larger than that.

Posted Image

This is from the same source. Image A shows NA 75 million years ago while Image B shows NA 65 million years ago. However, it is making much more sense that the Western Interior Seaway would be larger at the end of the Cretaceous than what Image B suggests and most likely much closer to what Image A shows with 3 NA subcontinents that separated the fauna. Out of curiosity, does anyone recall what is the name of the 3rd subcontinent in the north next to Greenland and what animals have been found there?
Edited by SamtheMan, Oct 27 2014, 11:03 PM.
Offline Profile Quote Post Goto Top
 
Incinerox
Member Avatar
Āeksiot Zaldrīzoti

SamtheMan
Oct 27 2014, 11:02 PM
Just to make things a little more clear, the image I posted was from a source that suggested that it was what North America looked like 65 million years ago, I know the Western Interior Seaway was much larger than that.

Posted Image

This is from the same source. Image A shows NA 75 million years ago while Image B shows NA 65 million years ago. However, it is making much more sense that the Western Interior Seaway would be larger at the end of the Cretaceous than what Image B suggests and most likely much closer to what Image A shows with 3 NA subcontinents that separated the fauna. Out of curiosity, does anyone recall what is the name of the 3rd subcontinent in the north next to Greenland and what animals have been found there?
I'm struggling to believe that either of those maps are accurate for Maastrichtian North America.

Every T. rex fossil found in the States seems to be directly IN the northern waters of what they've presented as the inland sea, when we know the areas spanning from Alberta and Saskatchewan, down through Montana and the Dakotas, right down to New Mexico were actually land by the time T. rex showed up in Hell Creek.

In other words, the world 65Ma probably looked more like this:
Posted Image
Edited by Incinerox, Oct 28 2014, 10:16 AM.
Offline Profile Quote Post Goto Top
 
Even
No Avatar


I still don't think that the WIS has dried up 100% even by the Maastrichtian...
Offline Profile Quote Post Goto Top
 
Furka
Member Avatar


AFAIk Hell Creek has some marine facies, and some animals found in it are from marine environments (ammonites, sharks, Belonostomus ...)
Offline Profile Quote Post Goto Top
 
Brach™
Member Avatar
hi

Lets keep in mind, the extinction event started 1.5 million years before 65mya.
Offline Profile Quote Post Goto Top
 
Incinerox
Member Avatar
Āeksiot Zaldrīzoti

Furka
Oct 28 2014, 01:05 PM
AFAIk Hell Creek has some marine facies, and some animals found in it are from marine environments (ammonites, sharks, Belonostomus ...)
Almost the aquatic species from Hell Creek I could find information on were excavated from freshwater deposits. Even the wobbegongs present were from freshwater areas. All of the aquatic vertebrates were freshwater species for sure as far I could gather.

The ONLY marine species I could find were all molluscs dug up from a small strip of marine deposition in South Dakota. So that'd be the absolute highest point where you'd have a narrow strip of seawater present in Hell Creek.

And like I said before, terrestrial species were relatively consistent right across from Alberta and Saskatchewan through Montana and the Dakotas, Wyoming, Colorado, and down to New Mexico and Texas. And while I can't confirm this, I wouldn't be surprised if that vast beech forest ecosystem spread right from Mexico itself to British Columbia, cutting through Utah.

Also, it's interesting to note that anywhere further east from these locations are only known really from marine rocks 10 million years older than Hell Creek deposits until you reach Appalachia, where we barely have anything anyway (like seriously, what DO we have?).

I'm currently trying to find as many end-cretaceous species from North America as possible to try and map out my own take of that inland sea. Nothing I've seen previously generated either in this topic or any website seems to match the species distributions at all. So far I've gotten through 40 odd T. rex fossil locations and 2 marine fossil sites that already make some things seem backwards-side down compared to the renders earlier in this topic.

That's all I can say until I've done a bit more...
B-)
Digging...
Edited by Incinerox, Oct 28 2014, 05:19 PM.
Offline Profile Quote Post Goto Top
 
BossAggron
Member Avatar
Formerly Dilophoraptor

Incinerox
Oct 28 2014, 05:19 PM
That's all I can say until I've done a bit more...
B-)
Digging...
Even here DG, even Here.

Anyways, I was wondering if there are any good maps of the Major Time Periods of the Mesozoic that could be useful.
Offline Profile Quote Post Goto Top
 
CyborgIguana
Member Avatar


You mean as in timelines, or maps of what the Earth looked like at various points of the Mesozoic?
Offline Profile Quote Post Goto Top
 
Brach™
Member Avatar
hi

Theres an end cretaceous deposit in Mantua, New Jersey I went with Drexel to dig at called Inversand. It was some kind of estuarine habitat with crocodilians, mosasaurs, turtles and shit loads of clam shells. At least in that habitat clams made up the bedrock of the food chain.

Imo New Jersey is probably one of the more Prolific states of fossil finds in the east. http://www.fossilsites.com/STATES/NJ.HTM
Edited by Brach™, Oct 28 2014, 09:50 PM.
Offline Profile Quote Post Goto Top
 
BossAggron
Member Avatar
Formerly Dilophoraptor

CyborgIguana
Oct 28 2014, 08:03 PM
You mean as in timelines, or maps of what the Earth looked like at various points of the Mesozoic?
Maps of the Mesozoic World, Mostly just those with Major Continental Movement or Sea Formation.
Offline Profile Quote Post Goto Top
 
3 users reading this topic (3 Guests and 0 Anonymous)
Go to Next Page
« Previous Topic · Extinct Animals & Evolution · Next Topic »
Add Reply