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What annoys you about paleontology?; Rant on about moronic theories, complaints, or just animals that annoy you.
Topic Started: Sep 28 2013, 05:04 PM (256,243 Views)
Incinerox
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@Paleosaurus: Oh, in that sense I totally agree.

@Babehunter: Oh s***! Alioramus was actually contemporaneous with Tarbosaurus! I suppose my point still kinda stands with Raptorex which was far older (I thought Alioramus was 5-10 million years older than Tarbosaurus itself, but it seems I am indeed wrong). But my point about them being different still stands. The fact that different species of Alioramus can be identified, alongside a more closely related genus than Tarbosaurus shoots the juvenile hypothesis down, and has done so for a while.
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babehunter1324
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Yeah I can recall that my old books claimed that Alioramus was from the Early/Mid Campanian (about 80 MYA) apparently the re-assesment as a contemporary to Tarbosaurus came latter (after 2005).

That makes me think about something. In Dinosaur Park we had Daspletosaurs and Gorgosaurus, in the Kaiparowits Formation we have Teratophoneus and Albertosaurus*, in Nemegt we had Tarbosaurus and Alioramus and in Hell Creek we may have Tyrannosaurus and Nanotyrannus. It seems that in several geological formations two different genus of Tyrannosauridae manage to coexist, I really wonder how they managed to partition their niche in between them.

* I'm kinda skeptic that the Albertosaurine in Kaiparowits was the same genus let alone species as the one in Horshoe Canyon (A. sarcophagus) considering the fact that the one in Utah is about 4-5 MY older and the distance that separated both regions (Edit: Also it's based in fragmentary remains from 2004).

Also did Teratophoneus and Bistahieversor (two of the most over the top scientific names ever, btw) coexist? I'm not sure...
Edited by babehunter1324, Feb 23 2015, 07:31 PM.
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Furka
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Quote:
 
That makes me think about something. In Dinosaur Park we had Daspletosaurs and Gorgosaurus, in the Kaiparowits Formation we have Teratophoneus and Albertosaurus*, in Nemegt we had Tarbosaurus and Alioramus and in Hell Creek we may have Tyrannosaurus and Nanotyrannus. It seems that in several geological formations two different genus of Tyrannosauridae manage to coexist, I really wonder how they managed to partition their niche in between them.


My personal Opinion?

1- Both seem to be built for different hunting tactics, with Das looking more like an ambush hunter rather than something that would chase hadrosaurs in the open. IIRC there was also the thing with one of the two being more common at certain latitudes. Plus, DP environment seems to have a great variety of herbivores, perhaps allowing predators to stay away from each other's prey
2- no idea
3- Again, great variety of prey species, and also size difference, Plus, if Alioramus did really have a long snout like Pinocchio rex, it ,ay have been more specialized in smaller prey than a similar sized Tarbo juvenile.
4- this is the one puzzling me the most. We don't know as many different prey items from HC as from Nemegt or DP (at least those that could be seen as regular prey by a big predator), and Nanotyrannus seems to be in direct competition with the young Tyrannosaurus (that is, if it was something else ...)
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babehunter1324
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I also think that Albertosaurines may had favoured more humid habitats than large Tyrannosaurines, I'm not sure about Gorgosaurus but both Albertosaurus and the Kaiparowits formation Albertosaurine came from areas that suffered very important seasonal flooding.
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CyborgIguana
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Personally I don't think Daspletosaurus and Gorgosaurus co-existing is any more puzzling than lions and leopards co-existing in present-day Africa.
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BossAggron
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Formerly Dilophoraptor

Isn't it kinda weird that many formations have a few contemporary carnivores where Hell Creek only has Tyrannosaurus rex in the large carnivore niche?
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Paleosaurus
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Dilophoraptor
Feb 23 2015, 10:59 PM
Isn't it kinda weird that many formations have a few contemporary carnivores where Hell Creek only has Tyrannosaurus rex in the large carnivore niche?
Clearly indicative that T.rex was the single most badass awesome predator to ever live. It's a wonder that it didn't start hopping through time and outcompeting other big theropods. One can dream.....

In all seriousness, though, I wonder if it had anything to do with the North American ecosystems being relatively low-diversity compared to ones from 10 million years prior. Less prey supports less predators, after all.
Edited by Paleosaurus, Feb 23 2015, 11:22 PM.
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Posted Image Guat
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Paleosaurus
Feb 23 2015, 11:21 PM
In all seriousness, though, I wonder if it had anything to do with the North American ecosystems being relatively low-diversity compared to ones from 10 million years prior. Less prey supports less predators, after all.
I'm pretty sure that was the case.
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Paleosaurus
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AVCDPS
Feb 23 2015, 11:24 PM
Paleosaurus
Feb 23 2015, 11:21 PM
In all seriousness, though, I wonder if it had anything to do with the North American ecosystems being relatively low-diversity compared to ones from 10 million years prior. Less prey supports less predators, after all.
I'm pretty sure that was the case.
That's an interesting problem for speculative no K/PG projects. Would tyrannosaurines even be able re-evolve moderate sizes before dromaeosaurids could take it? Usually you see projects with gracile and robust tyrannosaurines and the maniraptorans stay small. I think a project with big tyrannosaurines and the medium-small predators being maniraptorans of Utahraptor size and smaller is more plausible and more interesting.
Edited by Paleosaurus, Feb 23 2015, 11:34 PM.
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BossAggron
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Formerly Dilophoraptor

Do we have possible Subspecie Dinosaur specimens?
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Incinerox
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SUBSPECIES... No.

It's practically impossible to be that specific in the fossil record. If you consider how we identify subspecies of birds, it's usually something like "Subspecies X is slightly redder than subspecies Y", or "Subspecies X is slightly larger than Subspecies Y and lives slightly further north". Stuff you can't really tell in the fossil record unless you have enough data to rule out individual variation.
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Furka
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Paleosaurus
Feb 23 2015, 11:21 PM
Dilophoraptor
Feb 23 2015, 10:59 PM
Isn't it kinda weird that many formations have a few contemporary carnivores where Hell Creek only has Tyrannosaurus rex in the large carnivore niche?
Clearly indicative that T.rex was the single most badass awesome predator to ever live. It's a wonder that it didn't start hopping through time and outcompeting other big theropods. One can dream.....

In all seriousness, though, I wonder if it had anything to do with the North American ecosystems being relatively low-diversity compared to ones from 10 million years prior. Less prey supports less predators, after all.
Acrocanthosaurus was just like that, too.

Of course, there' still the chance HC had more herbivores that we don't know yet. The Therizinosaur astragalus is the proof of at least one more animal living there (I wish we knew more, so I could have added it to my story), and who knows if some of the bones that were just labeled as Triceratops/Edmontosaurus actually belonged to some other genus ...
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Incinerox
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Furka
Feb 24 2015, 05:27 AM
Acrocanthosaurus was just like that, too.
Not quite.

It did coexist with Deinonychus. Yes, it was the only LARGE theropod in the area, but as we do know, Deinonychus was indeed hunting large game of its own.

T. rex literally had ZERO competition in its environment. UNLESS Nanotyrannus turns out to be valid. In which case T. rex faced competition in the Lance Formation.
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babehunter1324
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Well I'm not sure that Deinonychus was much more valid competitor for multi-ton predator than Acheroraptor was (OFC we don't know enough about Acheroraptor to know if it also could hunt medium sized animals like Deinonychus did).

I might be wrong but I think one of the reasons why the biodiversity during the Late Maastritchian wans't as big as during the late Campanian may had something to do with the fact that there wasn't as much isolation as during the Campanian due to the shrinking of the Western Interior Seaway resulting in less habitat heterogeny and permiting more fauna interchange across Laramidia (which may reduce the overall biodiversity).
Edited by babehunter1324, Feb 24 2015, 10:35 AM.
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CyborgIguana
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People who still use the term "dinosaur" to refer to anything obsolete or inefficient.
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