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"The bladder of amphibians is thought to be homologous with the allantois (a fetal excretory organ) of amniotes. The bladder of turtles, Sphenodon and some lizards is formed by retention of part of the fetal allantois. Bladders are absent in crocodilians, snakes, some lizards, and most birds, because the urine of these is semisolid, consisting mostly of uric acid. In mammals the bladder is formed from part of the allantois and from the urodeum (a subdivision of the cloaca). The bladder empties into the cloaca in tetrapods except for therian mammals, in which it has a separate external opening called the urethra."
http://www.lifesci.utexas.edu/courses/bio478L/LecturesPDF/kidney.pdf.
"The bladder and the urethra develop from the urogenital sinus. The bladdder also develops in part from the allantois. The hindgut and the allantois empty into the cloaca early in development. The cloaca ends as the cloacal plate, a region of ectoderm and endoderm without intervening mesoderm. The urorectal septum develops in that region of the cloaca where the allantois and the hindgut meet. This septum grows toward the cloacal plate and divides it into an anal canal and a urogenital sinus. The cloacal plate then gets divided into an anal membrane and a urogenital membrane with a perineal body in between. The mesonephric duct empties into the urogenital sinus. The urogenital sinus and the allantois enlarge to form the urinary bladder."
http://isc.temple.edu/marino/embryology/Kidney98/kidney_text.htm
As far as I can see, the allantois does contribute to the formation of the urinary bladder in amniotes.
in the cladogram, having an image of a bird for diapsids might demonstrate diversity better. many other taxa use lizard-like organisms for their images already. — Preceding unsigned comment added by 96.70.198.37 ( talk) 13:55, 27 March 2019 (UTC)
Is there a published reference for referring Aminota to the rank of Microphylum? If so, it should be listed and discussed in the text, especially as I've seen this being migrated to taxoboxes on other pages. Dinoguy2 22:01, 17 August 2006 (UTC)
The Taxonomy section shows the Class Synasida containing the Order Therapsida, which in turn contains the Class Mammalia. You really can't mix traditional classification and cladistics this way.This needs to organized like Synapsid is. -- Donald Albury 22:55, 5 February 2007 (UTC)
Erm, we need one. Badly. Samsara ( talk • contribs) 14:45, 3 June 2007 (UTC)
Based on this and related articles, it seems that synapsids and sauropsids are two different lineages of amniotes which have evolved separately and are not directly related to one another. This means that "amniota" is a polyphyletic group, and therefore it is not a valid clade by the standards of modern cladistics. Is this correct? —Preceding unsigned comment added by 79.179.255.83 ( talk) 15:26, 29 March 2008 (UTC)
The Out of the swamps external link does not work, when I tried to get on it it said "HTTP 404 not found" —Preceding unsigned comment added by Phthinosuchusisanancestor ( talk • contribs) 21:40, 14 November 2008 (UTC)
I am a mammal, and I have two legs (last I checked). 75.118.170.35 ( talk) 19:59, 10 September 2009 (UTC)
The ranked taxonomy of amniotes taken from Benton is not really phylogenetic. At best it is a hybrid of the "traditional" system and a phylogenetic classificiation. I don not believe that it is very widely used. The (or a) real phylogenetic classification is the one given in the cladogram: in phylogenetics a cladogram and a classification are one in the same. As written the article also gives the impression that the "traditional" system still is in widespread use. It is not, although it persists in some textbooks. Struvite ( talk) 16:26, 9 March 2010 (UTC)
The amniote egg traditionally has been considered a major evolutionary advance that permitted vertebrates to reproduce on dry land, freeing them of the need to return to standing water. I intend to revise this article (with references) to reflect recent challenges to this view, and in particular to point out that 1. we have no direct evidence, and essentially no indirect evidence, of how the first amniotes or their ancestors reproduced. There is no reason to assume that the reproductive mode of modern amphibians is primitive or that the amniote egg evolved from anything resembling a frog egg. Some of the features of amniote eggs that have been interpreted as adaptations to terrestrial reproduction may in fact be primitive. 2. Amniote eggs provide no more protection from dehydration than amphbian eggs, even modern amphibian eggs. Eggs buried in underground nests need no such protection as the water potential of soil in such nests is higher than the physiological water potential of vertebrate eggs. 3. buildup of nitrogenous waste in terrestrial eggs is not the serious problem it often is assumed to be. 4. Terrestrial eggs need no special adaptations for gas exchange.
It may be best to create a separate section dealing with the amniote egg.
I'm new here and wanted to give a heads up before I make a lot of changes Struvite ( talk) 17:06, 9 March 2010 (UTC)
In the lede, the first amniotes are described as The first amniotes (referred to as "basal amniotes" or "stem amniotes"). This is misleading, as it indicates the stem group amniotes are limited to to the proper egg-laying animals. While "basal amniotes" is not a very precise term, stem amniota denotes a very wide assemblage, including most of (if not all) of the groups traditionally assigned to Reptiliomorpha, including Seymouria, Eogyrinus and Archeria, not to mention quite a few fossil tadpoles. The labyrinthodont tree is not well understood, and the actual content of "stem amniota" is a matter of some dispute, and may even contain some groups traditionally assigned to Temnospondyli. As such, the term "stem amniotes" is useless, and I have removed it from the lede. Petter Bøckman ( talk) 07:09, 4 May 2011 (UTC)
With the Mesosauridae evolving within the Parareptilia (= Anapsida). Sauropsida should be considered a junior synonym of Reptilia.
Tsuji, L. A., and J. Müller. 2009. Assembling the history of the Parareptilia: phylogeny, diversification, and a new definition of the clade. Fossil Record, 12(1): 71-81.
Modesto, S. P. 2006. The cranial skeleton of the Early Permian aquatic reptile Mesosaurus tenuidens: implications for relationships and palaeobiology. Zoological Journal of the Linnean Society, 146: 345-368. Ronald Van Heest ( talk) 14:07, 5 September 2010 (UTC)
Please see the discussion at Template talk:Taxonomy/Teleostomi, where we are discussing how to handle the taxon Eugnathostomata. Bob the WikipediaN ( talk • contribs)
The third paragraph of the lede says: The first amniotes, referred to as "basal amniotes", resembled small lizards and evolved from the amphibian reptiliomorphs about 312 million years ago,[2]. This doesn't look right. The conventional date is 340 mya. The statement is not supported by the source, which gives 312-330 as the date for the Saurapsid/Synapsid split, which would be the crown group. Zyxwv99 ( talk) 04:30, 7 March 2015 (UTC)
I am confused about the references to Infraclass. For example, it looks as if under the clade "Infraclass Diapsida" there are "Infraclass Neodiapsida" and "Infraclass Lepidosauromorpha". Should there be a different designation for the clade "Diapsida"? TomS TDotO ( talk) 21:30, 8 August 2020 (UTC)
Talk- Amniote/Reptile debate- I do not want to get in trouble, so I am writing in this talk page before I edit anything, but the strict split of synapsids as non-reptiles and sauropsids as reptiles including birds that I see on other wikipedia pages is inaccurate. Amniotes, at least all reptiliomorphs, are in fact the best definition of reptiles, not sauropsids. Synapsids and sauropsids are two major branches of reptiles/ reptiliomorphs. Should we make amniotes equivalent to reptiles or make the main group reptiliomorphs. In taxonomic terms, where should we put the crown group of reptiles? It is is not as the sauropsid level but above that. — Preceding unsigned comment added by Cbinetti ( talk • contribs) 22:22, 6 June 2022 (UTC)
@ I heard you like clades has recently edited the larger cladogram in the article. I've noticed that it poorly fits when displayed on both my phone's and my computer's screen. I checked what it looked like before the edit, and it had the same/similar issue. Is there some way to fix this? At least so I can scroll past the last image so that the Archosauriformes aren't crammed in the bottom left of my screen.
Another issue is that when scrolling through the cladogram on my phone, my screen is often entirely empty. This makes navigation and keeping the relationships of thing in mind a tad confusing at times. I know that it'll be hard to display so much info in an aesthetic manner but I thought that it would be a nice improvement.
Could the functionality be added to allow the cladogram to be opened in a different tab as an image or pdf file? That might help. FropFrop ( talk) 03:33, 5 January 2024 (UTC)
This
level-5 vital article is rated Start-class on Wikipedia's
content assessment scale. It is of interest to the following WikiProjects: | |||||||||||||||||||||||||||||||
|
"The bladder of amphibians is thought to be homologous with the allantois (a fetal excretory organ) of amniotes. The bladder of turtles, Sphenodon and some lizards is formed by retention of part of the fetal allantois. Bladders are absent in crocodilians, snakes, some lizards, and most birds, because the urine of these is semisolid, consisting mostly of uric acid. In mammals the bladder is formed from part of the allantois and from the urodeum (a subdivision of the cloaca). The bladder empties into the cloaca in tetrapods except for therian mammals, in which it has a separate external opening called the urethra."
http://www.lifesci.utexas.edu/courses/bio478L/LecturesPDF/kidney.pdf.
"The bladder and the urethra develop from the urogenital sinus. The bladdder also develops in part from the allantois. The hindgut and the allantois empty into the cloaca early in development. The cloaca ends as the cloacal plate, a region of ectoderm and endoderm without intervening mesoderm. The urorectal septum develops in that region of the cloaca where the allantois and the hindgut meet. This septum grows toward the cloacal plate and divides it into an anal canal and a urogenital sinus. The cloacal plate then gets divided into an anal membrane and a urogenital membrane with a perineal body in between. The mesonephric duct empties into the urogenital sinus. The urogenital sinus and the allantois enlarge to form the urinary bladder."
http://isc.temple.edu/marino/embryology/Kidney98/kidney_text.htm
As far as I can see, the allantois does contribute to the formation of the urinary bladder in amniotes.
in the cladogram, having an image of a bird for diapsids might demonstrate diversity better. many other taxa use lizard-like organisms for their images already. — Preceding unsigned comment added by 96.70.198.37 ( talk) 13:55, 27 March 2019 (UTC)
Is there a published reference for referring Aminota to the rank of Microphylum? If so, it should be listed and discussed in the text, especially as I've seen this being migrated to taxoboxes on other pages. Dinoguy2 22:01, 17 August 2006 (UTC)
The Taxonomy section shows the Class Synasida containing the Order Therapsida, which in turn contains the Class Mammalia. You really can't mix traditional classification and cladistics this way.This needs to organized like Synapsid is. -- Donald Albury 22:55, 5 February 2007 (UTC)
Erm, we need one. Badly. Samsara ( talk • contribs) 14:45, 3 June 2007 (UTC)
Based on this and related articles, it seems that synapsids and sauropsids are two different lineages of amniotes which have evolved separately and are not directly related to one another. This means that "amniota" is a polyphyletic group, and therefore it is not a valid clade by the standards of modern cladistics. Is this correct? —Preceding unsigned comment added by 79.179.255.83 ( talk) 15:26, 29 March 2008 (UTC)
The Out of the swamps external link does not work, when I tried to get on it it said "HTTP 404 not found" —Preceding unsigned comment added by Phthinosuchusisanancestor ( talk • contribs) 21:40, 14 November 2008 (UTC)
I am a mammal, and I have two legs (last I checked). 75.118.170.35 ( talk) 19:59, 10 September 2009 (UTC)
The ranked taxonomy of amniotes taken from Benton is not really phylogenetic. At best it is a hybrid of the "traditional" system and a phylogenetic classificiation. I don not believe that it is very widely used. The (or a) real phylogenetic classification is the one given in the cladogram: in phylogenetics a cladogram and a classification are one in the same. As written the article also gives the impression that the "traditional" system still is in widespread use. It is not, although it persists in some textbooks. Struvite ( talk) 16:26, 9 March 2010 (UTC)
The amniote egg traditionally has been considered a major evolutionary advance that permitted vertebrates to reproduce on dry land, freeing them of the need to return to standing water. I intend to revise this article (with references) to reflect recent challenges to this view, and in particular to point out that 1. we have no direct evidence, and essentially no indirect evidence, of how the first amniotes or their ancestors reproduced. There is no reason to assume that the reproductive mode of modern amphibians is primitive or that the amniote egg evolved from anything resembling a frog egg. Some of the features of amniote eggs that have been interpreted as adaptations to terrestrial reproduction may in fact be primitive. 2. Amniote eggs provide no more protection from dehydration than amphbian eggs, even modern amphibian eggs. Eggs buried in underground nests need no such protection as the water potential of soil in such nests is higher than the physiological water potential of vertebrate eggs. 3. buildup of nitrogenous waste in terrestrial eggs is not the serious problem it often is assumed to be. 4. Terrestrial eggs need no special adaptations for gas exchange.
It may be best to create a separate section dealing with the amniote egg.
I'm new here and wanted to give a heads up before I make a lot of changes Struvite ( talk) 17:06, 9 March 2010 (UTC)
In the lede, the first amniotes are described as The first amniotes (referred to as "basal amniotes" or "stem amniotes"). This is misleading, as it indicates the stem group amniotes are limited to to the proper egg-laying animals. While "basal amniotes" is not a very precise term, stem amniota denotes a very wide assemblage, including most of (if not all) of the groups traditionally assigned to Reptiliomorpha, including Seymouria, Eogyrinus and Archeria, not to mention quite a few fossil tadpoles. The labyrinthodont tree is not well understood, and the actual content of "stem amniota" is a matter of some dispute, and may even contain some groups traditionally assigned to Temnospondyli. As such, the term "stem amniotes" is useless, and I have removed it from the lede. Petter Bøckman ( talk) 07:09, 4 May 2011 (UTC)
With the Mesosauridae evolving within the Parareptilia (= Anapsida). Sauropsida should be considered a junior synonym of Reptilia.
Tsuji, L. A., and J. Müller. 2009. Assembling the history of the Parareptilia: phylogeny, diversification, and a new definition of the clade. Fossil Record, 12(1): 71-81.
Modesto, S. P. 2006. The cranial skeleton of the Early Permian aquatic reptile Mesosaurus tenuidens: implications for relationships and palaeobiology. Zoological Journal of the Linnean Society, 146: 345-368. Ronald Van Heest ( talk) 14:07, 5 September 2010 (UTC)
Please see the discussion at Template talk:Taxonomy/Teleostomi, where we are discussing how to handle the taxon Eugnathostomata. Bob the WikipediaN ( talk • contribs)
The third paragraph of the lede says: The first amniotes, referred to as "basal amniotes", resembled small lizards and evolved from the amphibian reptiliomorphs about 312 million years ago,[2]. This doesn't look right. The conventional date is 340 mya. The statement is not supported by the source, which gives 312-330 as the date for the Saurapsid/Synapsid split, which would be the crown group. Zyxwv99 ( talk) 04:30, 7 March 2015 (UTC)
I am confused about the references to Infraclass. For example, it looks as if under the clade "Infraclass Diapsida" there are "Infraclass Neodiapsida" and "Infraclass Lepidosauromorpha". Should there be a different designation for the clade "Diapsida"? TomS TDotO ( talk) 21:30, 8 August 2020 (UTC)
Talk- Amniote/Reptile debate- I do not want to get in trouble, so I am writing in this talk page before I edit anything, but the strict split of synapsids as non-reptiles and sauropsids as reptiles including birds that I see on other wikipedia pages is inaccurate. Amniotes, at least all reptiliomorphs, are in fact the best definition of reptiles, not sauropsids. Synapsids and sauropsids are two major branches of reptiles/ reptiliomorphs. Should we make amniotes equivalent to reptiles or make the main group reptiliomorphs. In taxonomic terms, where should we put the crown group of reptiles? It is is not as the sauropsid level but above that. — Preceding unsigned comment added by Cbinetti ( talk • contribs) 22:22, 6 June 2022 (UTC)
@ I heard you like clades has recently edited the larger cladogram in the article. I've noticed that it poorly fits when displayed on both my phone's and my computer's screen. I checked what it looked like before the edit, and it had the same/similar issue. Is there some way to fix this? At least so I can scroll past the last image so that the Archosauriformes aren't crammed in the bottom left of my screen.
Another issue is that when scrolling through the cladogram on my phone, my screen is often entirely empty. This makes navigation and keeping the relationships of thing in mind a tad confusing at times. I know that it'll be hard to display so much info in an aesthetic manner but I thought that it would be a nice improvement.
Could the functionality be added to allow the cladogram to be opened in a different tab as an image or pdf file? That might help. FropFrop ( talk) 03:33, 5 January 2024 (UTC)