|
|
Post by EmperorDinobot on May 29, 2009 2:41:17 GMT
 Clidastes the mosasaur. |
|
|
|
Post by Dan on May 29, 2009 3:08:17 GMT
Impressive. But what happened to your "dinosaurs only" clause?
|
|
|
|
Post by EmperorDinobot on May 29, 2009 4:18:19 GMT
Mesozoic animals.
|
|
|
|
Post by Dan on May 29, 2009 5:23:08 GMT
There were rodents during the Mesozoic.
|
|
|
|
Post by stoneage on May 29, 2009 10:54:22 GMT
There were rodents during the Mesozoic. ;D YES!!!! |
|
|
|
Post by sbell on May 29, 2009 13:35:22 GMT
There were rodents during the Mesozoic. ;D YES!!!! No, there weren't. There were multituberculates, that had a similar incisor structure but very different molars and morphology (and are a separate mammal group from placentals or marsupials) and who went extinct possibly because of competition with rodents in the Eocene; and zalambdalestids are Mesozoic mammals that may have been ancestral to the rodent/lagomorph group (Glires--but this is controversial) but rodents themselves weren't around yet. |
|
|
|
Post by Tyrannax on May 29, 2009 15:02:10 GMT
No, there weren't. There were multituberculates, that had a similar incisor structure but very different molars and morphology (and are a separate mammal group from placentals or marsupials) and who went extinct possibly because of competition with rodents in the Eocene; and zalambdalestids are Mesozoic mammals that may have been ancestral to the rodent/lagomorph group (Glires--but this is controversial) but rodents themselves weren't around yet. I was going to post that rodents weren't around, but upon reading your post, you certainly go more into detail on mesozoic mammals. After all, stagodont marsupials, like didelphodon, were really the only mammals around at the time (The Cretaceous was especially full of primitive marsupials) - with the exception of a few of course. |
|
|
|
Post by sbell on May 29, 2009 15:30:20 GMT
No, there weren't. There were multituberculates, that had a similar incisor structure but very different molars and morphology (and are a separate mammal group from placentals or marsupials) and who went extinct possibly because of competition with rodents in the Eocene; and zalambdalestids are Mesozoic mammals that may have been ancestral to the rodent/lagomorph group (Glires--but this is controversial) but rodents themselves weren't around yet. I was going to post that rodents weren't around, but upon reading your post, you certainly go more into detail on mesozoic mammals. After all, stagodont marsupials, like didelphodon, were really the only mammals around at the time (The Cretaceous was especially full of primitive marsupials) - with the exception of a few of course. Other than mutlituberculates. And Cimolestids. And Zalambdalestids... This list gives a good idea of how varied they actually were--there are a lot of groups (even primitive artiodactyls!). Although obviously they were from various places and times within the Cretaceous. en.wikipedia.org/wiki/Category:Cretaceous_mammals |
|
|
|
Post by Tyrannax on May 29, 2009 15:55:59 GMT
I was going to post that rodents weren't around, but upon reading your post, you certainly go more into detail on mesozoic mammals. After all, stagodont marsupials, like didelphodon, were really the only mammals around at the time (The Cretaceous was especially full of primitive marsupials) - with the exception of a few of course. Other than mutlituberculates. And Cimolestids. And Zalambdalestids... This list gives a good idea of how varied they actually were--there are a lot of groups (even primitive artiodactyls!). Although obviously they were from various places and times within the Cretaceous. en.wikipedia.org/wiki/Category:Cretaceous_mammalsI was rather rough with that statement - I meant animals similar to Didelphodon (Anatomical size and looks) were abundant animals during the Cretaceous. Large, and dog-like. I see many animal groups in this list that have rodent-like teeth. Maybe a closer relative? |
|
|
|
Post by sbell on May 29, 2009 16:27:05 GMT
Other than mutlituberculates. And Cimolestids. And Zalambdalestids... This list gives a good idea of how varied they actually were--there are a lot of groups (even primitive artiodactyls!). Although obviously they were from various places and times within the Cretaceous. en.wikipedia.org/wiki/Category:Cretaceous_mammalsI was rather rough with that statement - I meant animals similar to Didelphodon (Anatomical size and looks) were abundant animals during the Cretaceous. Large, and dog-like. I see many animal groups in this list that have rodent-like teeth. Maybe a closer relative? For the most part, those will be multituberculates--it's a convergence; as a group, they do not even fall with modern placentals (unless that has changed recently)--they are part of the Allotheria, which is entirely separate. |
|
|
|
Post by Tyrannax on May 29, 2009 16:59:39 GMT
I was rather rough with that statement - I meant animals similar to Didelphodon (Anatomical size and looks) were abundant animals during the Cretaceous. Large, and dog-like. I see many animal groups in this list that have rodent-like teeth. Maybe a closer relative? For the most part, those will be multituberculates--it's a convergence; as a group, they do not even fall with modern placentals (unless that has changed recently)--they are part of the Allotheria, which is entirely separate. Allotheria sounded familiar- it turns out, after looking it up, this subclass was mentioned in one of my Tyrannosaurus (Sue) books, called "Rex Appeal" (Funny name btw) Conveniently, I can now use Allotheria as a substitute for my "Didelphodon similarity" statement I mentioned a few posts ago. This is exactly what I was intending to say. Which group exactly may have developed into placentals? - Bats, mice, rats, etc. |
|
|
|
Post by sbell on May 29, 2009 17:37:51 GMT
For the most part, those will be multituberculates--it's a convergence; as a group, they do not even fall with modern placentals (unless that has changed recently)--they are part of the Allotheria, which is entirely separate. Allotheria sounded familiar- it turns out, after looking it up, this subclass was mentioned in one of my Tyrannosaurus (Sue) books, called "Rex Appeal" (Funny name btw) Conveniently, I can now use Allotheria as a substitute for my "Didelphodon similarity" statement I mentioned a few posts ago. This is exactly what I was intending to say. Which group exactly may have developed into placentals? - Bats, mice, rats, etc. Those are already all placentals. As for what evolved into Therians, I haven't looked into it much--but I believe there is evidence that they evolved from a marsupial line (and of course co-existed for quite some time). In the Mesozoic, all of the major branches were represented, not just the allotherians (monotremes, marsupials, allotheres, placentals, etc). |
|
|
|
Post by Tyrannax on May 29, 2009 18:42:30 GMT
I know. I was just giving some examples of what placentals were as to just simplify things in general.
The marsupial line is suspected of evolving into Therians? Interesting how we are possibly descendants of marsupials. It is also interesting how marsupials have not lost their pouches. These appendages have not changed dramatically over millions of years to my knowledge. The pouches are still used for nurturing and teaching their brood while maintaining safety. Obviously this was a very successful evolutionary advantage..
|
|
|
|
Post by EmperorDinobot on May 30, 2009 13:44:49 GMT
I am willing to draw anything mesozoic except mammals, mammaloids and mammal like animals unless they are still 100% reptilian. I &%#$&$%# hate mammals.
They make no sense.
|
|
|
|
Post by stoneage on Jun 10, 2009 22:06:40 GMT
No, there weren't. There were multituberculates, that had a similar incisor structure but very different molars and morphology (and are a separate mammal group from placentals or marsupials) and who went extinct possibly because of competition with rodents in the Eocene; and zalambdalestids are Mesozoic mammals that may have been ancestral to the rodent/lagomorph group (Glires--but this is controversial) but rodents themselves weren't around yet. Techniquely Bell is correct. However mammals are just very advanced Therapsids Synapsids. During the late Triassic until the Middle Cretaceous Tritylodontids existed, although Chronoperates may be one exception which lived in the Paleocene. They were small to medium sized extremely mammal-like cyncodonts. They have been found in the Americas, South Africa and Eurasia. The Tritylodonts can very much be seen as Mesozoic rodents. The appearance of these animals can be compared to that of mink, weasel, otter, the hare, and the ferret. Just like rodents they did not have canines. It would grind its food between the teeth in somewhat the same way as modern rodents would with their food. They also stood with there legs straight below their bodies unlike other Synapsids. If you were to see many of the Mesozoic Mammals in person you would probably identify them as rodents. Megazostrodon for instance looks like a shrew. en.wikipedia.org/wiki/MegazostrodonMany of thes remains are found in Liaoning, China along with most of the so-called Feathered Dinosaurs. Also studys show that Placental Mammals existed at least in the Late Cretaceous 10 Million Years before the K-T Boundry. Placentals make up 95% of the Cenozoic mammals. On the other hand, Archaeopteryx is often called the "First Bird". But it may actually may be less closely related to modern birds than are Deinonychosaurs. It doesn't look anymore like a bird then Megazostrodon does a rodent. In fact in my opinion less. Modern style Birds didn't show up till the Late Cretaceous with the exception of Gallornis (Early Cretaceous). Of these only Antatalavis seems to have made it across the K-T Boundry. At any rate it seems to me if we can call primitive Dinosaurs Birds, then we can call many primitive Mammals Rodents. ;D |
|
|
|
Post by Dan on Jun 10, 2009 22:21:19 GMT
I am willing to draw anything mesozoic except mammals, mammaloids and mammal like animals unless they are still 100% reptilian. I &%#$&$%# hate mammals. They make no sense. Batman is a mammal. |
|
|
|
Post by sbell on Jun 11, 2009 0:02:24 GMT
No, there weren't. There were multituberculates, that had a similar incisor structure but very different molars and morphology (and are a separate mammal group from placentals or marsupials) and who went extinct possibly because of competition with rodents in the Eocene; and zalambdalestids are Mesozoic mammals that may have been ancestral to the rodent/lagomorph group (Glires--but this is controversial) but rodents themselves weren't around yet. Techniquely Bell is correct. However mammals are just very advanced Therapsids Synapsids. During the late Triassic until the Middle Cretaceous Tritylodontids existed, although Chronoperates may be one exception which lived in the Paleocene. They were small to medium sized extremely mammal-like cyncodonts. They have been found in the Americas, South Africa and Eurasia. The Tritylodonts can very much be seen as Mesozoic rodents. The appearance of these animals can be compared to that of mink, weasel, otter, the hare, and the ferret. Just like rodents they did not have canines. It would grind its food between the teeth in somewhat the same way as modern rodents would with their food. They also stood with there legs straight below their bodies unlike other Synapsids. If you were to see many of the Mesozoic Mammals in person you would probably identify them as rodents. Megazostrodon for instance looks like a shrew. en.wikipedia.org/wiki/MegazostrodonMany of thes remains are found in Liaoning, China along with most of the so-called Feathered Dinosaurs. Also studys show that Placental Mammals existed at least in the Late Cretaceous 10 Million Years before the K-T Boundry. Placentals make up 95% of the Cenozoic mammals. On the other hand, Archaeopteryx is often called the "First Bird". But it may actually may be less closely related to modern birds than are Deinonychosaurs. It doesn't look anymore like a bird then Megazostrodon does a rodent. In fact in my opinion less. Modern style Birds didn't show up till the Late Cretaceous with the exception of Gallornis (Early Cretaceous). Of these only Antatalavis seems to have made it across the K-T Boundry. At any rate it seems to me if we can call primitive Dinosaurs Birds, then we can call many primitive Mammals Rodents. ;D As someone that spent too many years studying fossil rodents, no, you can't call them rodents. That would be like calling all primates people. Rodents are defined by a very specific zygomasseteric structure, a single pair of ever-growing incisors on in the upper and lower dental batteries, and a unique fore-aft chewing mechanism reflected in the molars. Not one of those animals you listed is even a rodent. And no, rabbits are not rodents. Mutlituberculates are the most likely Mesozoic mammal--they also have the incisors, but their molars are designed as bumpy mashers. Maybe we could just call them early mammals? |
|
|
|
Post by stoneage on Jun 11, 2009 1:22:10 GMT
Techniquely Bell is correct. However mammals are just very advanced Therapsids Synapsids. During the late Triassic until the Middle Cretaceous Tritylodontids existed, although Chronoperates may be one exception which lived in the Paleocene. They were small to medium sized extremely mammal-like cyncodonts. They have been found in the Americas, South Africa and Eurasia. The Tritylodonts can very much be seen as Mesozoic rodents. The appearance of these animals can be compared to that of mink, weasel, otter, the hare, and the ferret. Just like rodents they did not have canines. It would grind its food between the teeth in somewhat the same way as modern rodents would with their food. They also stood with there legs straight below their bodies unlike other Synapsids. If you were to see many of the Mesozoic Mammals in person you would probably identify them as rodents. Megazostrodon for instance looks like a shrew. en.wikipedia.org/wiki/MegazostrodonMany of thes remains are found in Liaoning, China along with most of the so-called Feathered Dinosaurs. Also studys show that Placental Mammals existed at least in the Late Cretaceous 10 Million Years before the K-T Boundry. Placentals make up 95% of the Cenozoic mammals. On the other hand, Archaeopteryx is often called the "First Bird". But it may actually may be less closely related to modern birds than are Deinonychosaurs. It doesn't look anymore like a bird then Megazostrodon does a rodent. In fact in my opinion less. Modern style Birds didn't show up till the Late Cretaceous with the exception of Gallornis (Early Cretaceous). Of these only Antatalavis seems to have made it across the K-T Boundry. At any rate it seems to me if we can call primitive Dinosaurs Birds, then we can call many primitive Mammals Rodents. ;D As someone that spent too many years studying fossil rodents, no, you can't call them rodents. That would be like calling all primates people. Rodents are defined by a very specific zygomasseteric structure, a single pair of ever-growing incisors on in the upper and lower dental batteries, and a unique fore-aft chewing mechanism reflected in the molars. Not one of those animals you listed is even a rodent. And no, rabbits are not rodents. Mutlituberculates are the most likely Mesozoic mammal--they also have the incisors, but their molars are designed as bumpy mashers. Maybe we could just call them early mammals?  Rabbits are not rodents, but except for the fact that they have double the number of incisors, a scrotum in front of the thingy, and no Baculum (thingy bone), they are very similiar. Both have teeth that grow throughout their lifetimes, and neccessitate constant chewing. The point is that scientist call Archaeopteryx a bird and it has teeth and a tail. So we can conclude that there were no birds during the mesozoic. ;D |
|
|
|
Post by sbell on Jun 11, 2009 3:32:43 GMT
As someone that spent too many years studying fossil rodents, no, you can't call them rodents. That would be like calling all primates people. Rodents are defined by a very specific zygomasseteric structure, a single pair of ever-growing incisors on in the upper and lower dental batteries, and a unique fore-aft chewing mechanism reflected in the molars. Not one of those animals you listed is even a rodent. And no, rabbits are not rodents. Mutlituberculates are the most likely Mesozoic mammal--they also have the incisors, but their molars are designed as bumpy mashers. Maybe we could just call them early mammals? Rabbits are not rodents, but except for the fact that they have double the number of incisors, a scrotum in front of the thingy, and no Baculum (thingy bone), they are very similiar. Both have teeth that grow throughout their lifetimes, and neccessitate constant chewing. The point is that scientist call Archaeopteryx a bird and it has teeth and a tail. So we can conclude that there were no birds during the mesozoic. ;D That wasn't the point of the original post at all--it was that true rodents were not their with the dinos (that we know of). Trying to create unrelated analogies with birds/dinos has nothing to do with it. |
|
|
|
Post by [][][]cordylus[][][] on Jun 11, 2009 3:39:23 GMT
Let's stop talking about mammals. Emp hates them.
|
|
Rabbits are not rodents, but except for the fact that they have double the number of incisors, a scrotum in front of the thingy, and no Baculum (thingy bone), they are very similiar. Both have teeth that grow throughout their lifetimes, and neccessitate constant chewing.![[][][]cordylus[][][] Avatar](http://files.sharenator.com/Troll_Face_U_MAD_RE_wrestling_1-s407x405-126802.jpg)
