Dinosaurs

[Coorinna]

Sooo. Some people are deciding to hold the specimens of a type of dinosaur for themselves. So nobody knows what the new dinosaur actually looks like. They need to stop being jerks like that.

An alarming amount of fossils are sold illegally, stolen or modified. Some fossils even end up in traditional medicine. Because fossilization is so rare we will only ever find and categorize a fraction of all the dinosaur species which ever lived anyway, and unfortunately there are many specimens which will never be formally described because of them being sold or destroyed.

 

I found a Hyaenodon jawbone for sale a while ago that I wanted, but I felt guilty after reading SVP's opposition to fossil collectors. No creodont mandibles for me.

 

So what even IS the deal with raptors? I've been hearing a lot about how now they're mostly thought to have been ambush predators that dropped down on things, because most of them had awful legs for running.

 

Not sure about how cursorial/speedy raptors are. The vast majority of them are lightly built, which often suggests quick and agile movement, though. I guess it would depend on their prey; I can't imagine the smaller dromaeosaurs having the need to run cheetah-fast when chasing small mammals or lizards. I often assume that raptors we find with heavily-feathered hind legs are ambush predators or gliders (Microraptor), since all those floofy feathers would have caused drag in a straight run.

[nlechoppa]

I am fine with those allowing study. But they are jerks who will not allow anybody to see or touch it or examine it.

[Coorinna]

If anyone's interested, there's a newly-published study attempting to disprove the traditional bird-dinosaur evolutionary relationship, using that adorable dinosaurian aye-aye mimic Scansoriopteryx as proof.

 

The only issue I have with this is Alan Feduccia's involvement - he's one of the very few scientists opposed to the bird-dinosaur connection and I get the impression that he's pretty notorious among the paleontological community for it.

 

I think I'll stick to the ordinary birds-are-dinosaurs hypothesis. Feathery dinosaurs ahoy!

Edited July 12, 2014 by Coorinna

[edwardelricfreak]

I'm pretty sure they're still related, too. :\ Until we find massive evidence that concludes without-a-doubt that birds didn't evolve from dinosaurs at all, I'm not buying it yet.

 

And why does it matter if it was "before Archaeopteryx"? I thought there were already other creatures that were very bird-like around the time and even before Archaeopteryx.

[nlechoppa]

Well there is a possibility and the thing is called convergent evolution. Flying insects bats and birds aren't particularly related but they learned how to fly.

[nlechoppa]

Assuming that Amphicoelias has the same proportions as D. Carnegii. It would be 75 meters long and weigh 263 tons.

[grimace]

Not sure about how cursorial/speedy raptors are. The vast majority of them are lightly built, which often suggests quick and agile movement, though. I guess it would depend on their prey; I can't imagine the smaller dromaeosaurs having the need to run cheetah-fast when chasing small mammals or lizards. I often assume that raptors we find with heavily-feathered hind legs are ambush predators or gliders (Microraptor), since all those floofy feathers would have caused drag in a straight run.

Yeah, their build is just weird. utahraptor has bizarrely short legs, which wouldnt make sense for something that ran down prey.

[Starscream]

When it comes to the dino's I can't help but think they are still living amongst us. I mean, Every time I look at a bird, I swear I am looking into the eyes of the only surviving line of these great prehistoric monsters. And beasts such as Emu and Ostrich really really haunt me with the Likeness of a dino. Those huge heavy scaled feet to those big all seeing reptilian eyes.

 

I think the great beasts died out, but the feathered ones or at least the smaller feathered ones, adapted well to whatever ended their reign. I don't think it ended as suddenly as, Friday night they all get back from the Dino Party and drunk on whatever ancient fruits that fermented and the following morning only birds and mammals survived. It could be that some survived whatever cataclysm ended the reign and they were unable to repopulate and the little birds and mammals were all about hey lets spread out.

 

There was that time between dinos and mammals that was age of the birds. There were giant birds called terror birds, or even more recently moas and giant eagles that fed upon them.

 

The image below - unfortunately with french text, but it pretty much covers the giant birds that lived Post dinosaur era and they themselves look quite like the raptors.

http://naturalishistoria.files.wordpress.c...giant-birds.jpg

 

my thoughts were the reptiles that survived had a fairly heavy feathered coat and could adapt to whatever change in climate there was.

 

Dinosaurs have been presumed to have warm blooded bodies, like birds, which would allow them sustained activity which cold blooded bodies do not. Birds are very active.

Dinosaurs lay eggs, and built nests, there is evidence that shows many dinosaurs were excellent parents. Most birds are very excellent parents.

 

On an interesting note. Duck Billed Platypus seem to be a lot like the ancient mammal-like reptiles. They produce milk to feed their young much like mammals and yet lay eggs much like reptiles. Dimetradons were considered a mammal-like reptile and quite possibly one creature from which the mammalian lines spring - don't quote me on it when I learned this... it was ages ago and this theory could be obliterated by now. \

 

I love dinosaurs and I love birds, so it excites me more and more when they discover evidence that suggest these great beasts were more feathery than scaly.

 

I sort of dived in with my own thoughts. Anyway cheers. don't eat me alive - I allow that only for my pet Pigeon.

~linked for page stretch~

Edited July 16, 2014 by _Z_

[grimace]

Woah, dodos were THAT big and bulky?

[edwardelricfreak]

Ha, Diatryma. While I love that name, its actual name is Gastornis.

 

The big question about them, though: were they carnivores? There's a big debate on whether their powerful jaws were meant for crushing bone or crushing tough vegetation/nuts/seeds. They have a really deep lower jaw. Also, they had rather short legs for such large creatures, so they may not have been too fast, which means they might have either been ambush predators or not carnivores at all (or maybe even omnivores). Some even think it was a pack hunter.

 

It looks like the legs were really strong, though. Maybe it wasn't super fast, but it was probably still a strong runner, maybe even had good stamina.

 

It didn't have a hooked beak (well, it might have been a bit pointy, but was definitely not the hook of, say, an eagle's beak), which is common in birds of prey, and their talons weren't very long or sharp, either. I'm not sure if those are exactly necessary, though, as most birds of prey now can fly, unlike Gastornis. A bird like Titanis, with its seemingly more lithe build and definitely hooked beak was more likely to be carnivorous, same with Phorusrhacos. Interestingly, Gastornis is more closely related to ducks and geese.

 

I'm thinking it was an herbivore or omnivore, feeding on plants and insects. o3o

 

Titani and Phorusrhacos, though? Those are awesome terror birds. They fill the void my childhood favorite Diatryma once reigned.

[nlechoppa]

Going on about Amphicoelias fragilis.

I'm confident it's bigger than just 60m and 120 tons

Rendering this size chart completely useless unless your going for a small one.

[Coorinna]

The giant flightless bird thing is something evolution really likes to repeat, with ratites, gastornids, phorusrhacids and more. I wouldn't say dodos are exactly giants, but they're certainly larger (and weirder) than anything else in the pigeon family.

 

The last thing I read about Gastornis was probably a plain ol' herbivore, which basically falsifies pretty much any depiction of them in art or movies, where they're always shown preying on some unspecified primitive ungulate. The beak does look somewhat similar to those of the recently-extinct and closely-related Australian dromornithids, which were mostly herbivorous too.

 

I guess the true terror birds really are the phorusrachids. Interestingly enough (and linking back to the discussion on raptor claws) their closest relative, the seriema does actually have little sickle claws on its feet which it uses when hunting.

[nlechoppa]

Gastornis doesn't really look predator built. It looks like a walking pigeon that can't fly. It though looks like it could hunt and I doubt its a herbivore maybe a omnivore. On the topic of raptors. I doubt Utahraptor could run very fast. It's a ambush predator probably. Dodos are quite robust for their size. And why wont anyone comment about me trying to scale a Amphicoelias fragilis.

[edwardelricfreak]

And why wont anyone comment about me trying to scale a Amphicoelias fragilis.

I was wrapped up with raptors and Gastornis.

 

Honestly I wouldn't be surprised if Amphicoelias fragilis was much larger or not. Sauropod size really doesn't surprise me any more. They're big. Some are long. Some are tall. I normally can't tell one from the other unless there's just something about them like crests or something. D: Actually some of that also goes towards other dinos, too. I wish I could learn about all of them, but some just get mixed up with the others because they're so similar.

[nlechoppa]

I'll try and scale him and see if he's bigger or smaller some other time. I did a quick horrible looking sketch of the vertebrate drawing. And used that to extrapolate size.

[nlechoppa]

Amphicoelias is the biggest. D carnegii is white hallorum in grey. Monster of minden is the grey theropod and Saurophaganax is the other theropod. Edited July 22, 2014 by Soulking

[YanaAlYanas]

What is a dinosaur?

[edwardelricfreak]

Dinosaurs are reptilian animals that first showed up during the Triassic period. Birds are considered a subgroup of dinosaurs, as birds evolved from theropod dinosaurs, which were bipedal saurischian dinosaurs. Most theropods were also carnivorous.

 

There are two major groups of dinosaurs: Ornithischia, aka bird-hipped, as their hip structure resembles that of a bird, and saurischia, aka lizard-hipped, as their hip structure resembles that of a lizard. Oddly enough, birds are classified under the saurischia group, despite their hips.

 

Under the ornithischians, you have many dinosaurs like Iguanadon, Triceratops, Pachycephalosaurus, Ankylosaurus, and Stegosaurus. Saurischians, on the other hand, include groups like the sauropods like Brachiosaurus, Diplodocus, and Apatasaurus (aka Brontosaurus), and the theropods like the infamous Tyrannosaurus Rex and various raptors like Velociraptor and Deinonychus.

 

Many dinosaurs could reach absolutely enormous size, as Soulking's reference picture shows. The largest dinosaurs belonged to the sauropod group, though there are some rather small ones as well. Many theropods had feathers, though they weren't quite as sophisticated as bird feathers are today. Those feathers were more like the downy undercoat that birds have, which made the dinosaurs mostly just look fuzzy. It's theorized that their feathers were mostly for thermoregulation. Some dinosaurs had particularly developed feathers, at least on their arms. Though they were not large enough and their arms weren't powerful enough to allow for flight, it's theorized that they may have been used for display and even gliding in some cases.

 

There are many other animals that are often confused with dinosaurs, but are not in fact actual dinosaurs. The most common are pterosaurs, mosasaurs, ichthyosaurs, plesiosaurs, and Dimetrodon. Dimetrodon was mammal-like reptile that lived during the Triassic period. Though it appeared very reptilian, it was actually more closely related with mammals. Mosasaurs, ichthyosaurs, and plesiosaurs were all various marine reptiles. Mosasaurs included Mosasaurus and Tylosaurus. They sort of resembled a cross between sharks, crocodiles, and monitor lizards, in a rough sense. Ichthyosaurs, which included Ichtyosaurus and many others, often resembled dolphins and whales due to convergent evolution. Plesiosaurs included Plesiosaurus and Elasmosaurus and sort of looked like marine sauropods, since most had very long necks (not all of them, for example Liopleurodon which looks more like a mosasaur, but many did). The Loch Ness Monster is often depicted as a plesiosaur. Pterosaurs were flying reptiles that included Pteranodon, Pterodactyl, Quetzalcoatlus, Rhamphorhynchus, Sordes, and Tapejara. Once believed to only be able to glide if they could take to the air at all, more research has found that pterosaurs were powerful fliers with strong muscles.

[nlechoppa]

Isn't Liopleurodon a pliosaur. I know it's still a plesiosaur but pliosaurs are ones to have short necks and powerful bites. Though Liopleurodon

was for sure not 15 meters. Documentaries show him as 25 meters. Which is just unimaginable.

Edited July 23, 2014 by Soulking

[edwardelricfreak]

Isn't Liopleurodon a pliosaur. I know it's still a plesiosaur but pliosaurs are ones to have short necks and powerful bites. Though Liopleurodon

was for sure not 15 meters. Documentaries show him as 25 meters. Which is just unimaginable.

Yes, it was. Pliosaurs were the short-necked plesiosaurs. I just think Liopleurodon in particular looked more like a mosasaur than anything.

[Starscream]

I was looking at an article today about a 4 wingged dinosaur, it had feathers on its rear legs that were a lot like wings and large feathers on its tail. They think it was quite capable of long distance gliding.

 

http://www.cbc.ca/news/technology/fossil-i...found-1.2708406

 

Kinda neat.

[grimace]

Isn't amphicoelias almost entirely guesswork? Like, even moreso than most other dinosaurs?

[nlechoppa]

Um not really. We have a drawing of the femur. And it's from cope who I don't doubt.

[grimace]

Um not really. We have a drawing of the femur. And it's from cope who I don't doubt.

I don't mean like that it didn't exist, but I mean the entire proportions/weight/length/look of it.

[edwardelricfreak]

I don't mean like that it didn't exist, but I mean the entire proportions/weight/length/look of it.

Yeah. Like we only have a drawing, and only of a femur. They might have had spines or weirdly-shaped heads and such, so it's mostly guesswork until more fossils are found.