|
|
Post by Horridus on Nov 19, 2009 17:07:35 GMT
I take issue with the Dracorex/Stygimoloch/Pachycephalosaurus theory. Why would a creature have smaller spikes as it grew older? Wouldn't it grow larger ones? I think the idea is that the spikes remained about the same size, at least on the periphery, but the rest of the skull and in particular the dome grew larger. A lot larger in the case of the dome. |
|
|
|
Post by lorenzovargas77 on Oct 4, 2011 18:20:10 GMT
Another one would be Guanlong/Monolophosaurus.
|
|
|
|
Post by dinoguy2 on Oct 5, 2011 0:40:49 GMT
Another one would be Guanlong/Monolophosaurus. Monolophosaurus lived several million years earlier so it's not likely to be the same species as Guanlong. |
|
|
|
Post by eriorguez on Oct 5, 2011 4:44:15 GMT
And Tyrannosauroids and Megalosaurs are quite different. I seriously wonder how the **** Greg Paul came to that conclusion.
|
|
|
|
Post by dyscrasia on Oct 5, 2011 10:35:46 GMT
Well, as more of an artist rather than a scientist (and also considering that he doesn't accept cladistics) he might have a certain viewpoint which differs from most other scientists when it comes to dinosaur classification.... even though it doesn't mean that I agree with him.
|
|
|
|
Post by bowheadwhale on Oct 22, 2011 18:26:26 GMT
While there are most certainly dinosaur species that are really the misidentified younger forms of others, I don't think it's safe to say that a third of known dinosaur species didn't exist. I take issue with the Dracorex/Stygimoloch/Pachycephalosaurus theory. Why would a creature have smaller spikes as it grew older? Wouldn't it grow larger ones? Not if they didn't need those spikes anymore. Look at Hoazin birds who have wing claws when they are chicks, claws that get worn out when they are adults. I agree totally with that "many small dinos were young dinos we all know". The triceratops skulls show a clear aging evolution. So do the pachycephalosaurus ones. |
|
|
|
Post by dinoguy2 on Oct 22, 2011 20:01:43 GMT
While there are most certainly dinosaur species that are really the misidentified younger forms of others, I don't think it's safe to say that a third of known dinosaur species didn't exist. I take issue with the Dracorex/Stygimoloch/Pachycephalosaurus theory. Why would a creature have smaller spikes as it grew older? Wouldn't it grow larger ones? Not if they didn't need those spikes anymore. Look at Hoazin birds who have wing claws when they are chicks, claws that get worn out when they are adults. I agree totally with that "many small dinos were young dinos we all know". The triceratops skulls show a clear aging evolution. So do the pachycephalosaurus ones. The spikes aren't that much smaller, the rest of the head is just bigger (also the spikes are larger if you take into account the keratin). |
|
|
|
Post by pawnosuchus on Oct 27, 2011 15:17:24 GMT
To reduce the species of dinosaurs by a third is in my opinion not warranted. I have no doubts that some species have been misidentified but certainly more research is called for. Even the Nanotyrannus controversy has not been totally settled. I do have a question though regarding the number of fossils. Haven't there been a great many more Triceratops fossils found than Torosaurus? And if this is true wouldn't numbers alone lead one to conclude that they are different species? Or is one to conclude it was rare for a Triceratops to reach full adulthood? Could be wrong about the numbers and maybe over simplifying. Comments?
|
|
|
|
Post by Griffin on Oct 27, 2011 16:28:00 GMT
To reduce the species of dinosaurs by a third is in my opinion not warranted. I have no doubts that some species have been misidentified but certainly more research is called for. Even the Nanotyrannus controversy has not been totally settled. I do have a question though regarding the number of fossils. Haven't there been a great many more Triceratops fossils found than Torosaurus? And if this is true wouldn't numbers alone lead one to conclude that they are different species? Or is one to conclude it was rare for a Triceratops to reach full adulthood? Could be wrong about the numbers and maybe over simplifying. Comments? Ur correct there are way more specimens dubbed triceratops than there are torosaurus. However apparently all known torosaurus skulls belong to fully grown adult animals. If they were indeed the same species one would have to wonder if there was a high mortality rate of animals before reaching this adult stage. If they were different species all along then where are the baby torosaurus? Personally I'm still leaning towards the different species idea but if more convincing evidence surfaces I may be swayed. |
|
|
|
Post by sbell on Oct 27, 2011 17:09:06 GMT
To reduce the species of dinosaurs by a third is in my opinion not warranted. I have no doubts that some species have been misidentified but certainly more research is called for. Even the Nanotyrannus controversy has not been totally settled. I do have a question though regarding the number of fossils. Haven't there been a great many more Triceratops fossils found than Torosaurus? And if this is true wouldn't numbers alone lead one to conclude that they are different species? Or is one to conclude it was rare for a Triceratops to reach full adulthood? Could be wrong about the numbers and maybe over simplifying. Comments? Ur correct there are way more specimens dubbed triceratops than there are torosaurus. However apparently all known torosaurus skulls belong to fully grown adult animals. If they were indeed the same species one would have to wonder if there was a high mortality rate of animals before reaching this adult stage. If they were different species all along then where are the baby torosaurus? Personally I'm still leaning towards the different species idea but if more convincing evidence surfaces I may be swayed. How many dinosaurs--or fossil organisms overall--do we have more than a handful of specimens? In an ideal world, we could identify the growth stages of every known species, but the reality is that we often don't even know the growth stages of many living organisms. So a lack of juveniles of one species is hardly d**ning evidence that it should be the adult of another species--especially since some Triceratops skulls look pretty 'adult' as they are. |
|
|
|
Post by Griffin on Oct 27, 2011 18:45:57 GMT
I guess I wasn't that clear in what I meant. Those two questions I brought up on opposite sides of the debate are if one is to assume one of the two theories. Yes of course the fossil record is spotty. We DO have an exceptionally large number of triceratops specimens on record though.
|
|
|
|
Post by pawnosuchus on Oct 27, 2011 21:23:55 GMT
I think that juveniles were less likely to fossilize. The lack of Torosaurus babies is certaintly understandable. I'd imagine that many dinosaur species are lacking juvenile specimens. My bias is showing through. I don't want to lose ANY species. ( Stiil get a pang of nostalgia when I look at my Marx Trachodons.)
|
|
|
|
Post by dinoguy2 on Oct 28, 2011 1:03:14 GMT
If we found a thousand torosaurus skeletons, unless the frills were preserved, they'd be called triceratops by default. Also it is expected that most fossils of a slow growing species will be of mid aged specimens, with a very few juvenile and a very few mature. See also t. Rex. Very few 40+ footers, very few Jane like juveniles, but lots of 35 footers.
|
|
|
|
Post by Horridus on Oct 28, 2011 13:10:20 GMT
( Stiil get a pang of nostalgia when I look at my Marx Trachodons.) I hope you weren't too attached to Anatotitan copei! |
|
|
|
Post by sbell on Oct 28, 2011 15:25:30 GMT
( Stiil get a pang of nostalgia when I look at my Marx Trachodons.) I hope you weren't too attached to Anatotitan copei! Or most of the Edmontosaurus species... |
|
|
|
Post by dinoguy2 on Oct 28, 2011 23:01:31 GMT
I hope you weren't too attached to Anatotitan copei! Or most of the Edmontosaurus species... Nah people only get attached to genera, which are fake, not species, which are somewhat more concrete. Nobody shed any tears for Edmontosaurus saskatchewanensis  |
|
|
|
Post by arioch on Oct 29, 2011 14:11:38 GMT
I was actually rather fond of Anatosaurus, but that was just in my childhood...
|
|
|
|
Post by dinoguy2 on Oct 29, 2011 19:30:30 GMT
I was actually rather fond of Anatosaurus, but that was just in my childhood... Actually, with Anatotitan gone and E. regalis restricted to the Campanian, there's really no reason not to bring Anatosaurus back. |
|
|
|
Post by arioch on Oct 29, 2011 19:48:42 GMT
What happened to Anatotitan? I´m out of the loop here...
(And what about Trachodon, while we´re on it?)
|
|
|
|
Post by dinoguy2 on Oct 29, 2011 21:07:59 GMT
What happened to Anatotitan? I´m out of the loop here... (And what about Trachodon, while we´re on it?) Trachodon is a nomen dubium based only on teeth. It may be a synonym of Brachylophosaurus, or it may be some undetermined, possibly already known lambeosaurine. Anatotian is probably just the mature growth stage of Edmontosaurus/Anatosaurs annectens. blogs.smithsonianmag.com/dinosaur/2011/10/goodbye-anatotitan/ |
|
