Talk:Sauropsida/Archive 1

Untitled
On their respective pages, Birds and Reptiles are listed as Classes, whereas on their page Dinosaurs are listed as a Superorder of Class Sauropsida. On this page, however, Birds, Reptiles and Dinosaurs are all included in Group Sauropsida. So we have it that Birds and Reptiles are Classes in the Class Sauropsida, while Dinosaurs are only a Superorder of Sauropsida seen as a Group.


 * This is the situation one end up with when mixing cladistic pylogeny with Linnaean ranks. The two systems are two ways of looking at classification, and do not mix too well. Cladistic groups (clades) are by their nature not ranked, as ranks are artificial constructs to make overview simpler and help remembering what critters are out there. The cladistic approach is to make a system of very precisely naming groups of organisms purely based on phylogeny, trading overview for precision. Shoehorning cladistic units like Sauropsida into a Linnean system will give strange results (as described).


 * As such, Sauropsida is a clade, not a class. Petter Bøckman (talk) 13:11, 24 February 2009 (UTC)

Parareptiles
I removed the section on Parareptilia. It was unsoruced, and as far as my knowledge goes, made no sense. Sauropsida and Theropsoda/Synapsida are defined within Amniota as a node-branch triplet. All Amniotes fall on one side or the other by definition. There can't be non-Sauropsid, non-Synapsid amniotes any more than there can be non-saurischian, non-ornithischian dinosaurs. If it falls outseide either clade, it also falls outside amniota. The cladograms on the Parareptilia page also seem to back this up, as none place parareptiles as basal to Synapsida. If some cite does, they'd appear to be in a small minority and should be treated as such. Dinoguy2 (talk) 14:56, 4 May 2009 (UTC)


 * I'm afraid that is not quite correct. Dinosauria is node based as you describe (as it was largely left undefined by Owen), but Amniota is apomorphy-based. Amniota was described by Haeckel in 1866, well before the concept of nodes. The only way a node based Amniota could be identical to an apomorphy-based Amniota would be if the same individual who laid the first amniote egg also laid an egg with the first synapsid (again apomorphy-based line) and the first Sauropsid, and you'd still be pressed to define their siblings.


 * That being said, the section was not very good, and could do with sourcing. I'll go through the history of classification of the Reptiles first, then see if some of it is useable here. Petter Bøckman (talk) 20:17, 5 May 2009 (UTC)
 * Not sure I follow. All taxa used to be apomorphy based, but I thought we were speaking of the cladistic sense in this article. Do you have a current citation for a cladistically-defined apomorphy-based definition for Amniota? Pre-ICPN, we should go with whatever definition most papers use, and I've not heard many use anything but Amniota=Sauropsida+Synapsida, with no reference to amniotic eggs (which rarely fossilize), but I could be wrong. Dinoguy2 (talk) 14:46, 6 May 2009 (UTC)
 * Just as a start to backing myself up, this link provides a good discussion: . It lists the definition of Amniota as "the most recent common ancestor of extant mammals and reptiles, and all its descendants" (Gauthier et al., 1988)." Dinoguy2 (talk) 14:51, 6 May 2009 (UTC)


 * That's the whole problem here. Different taxa has different forms of definitions. Vertebrata, Tetrapoda, Reptilia, Diapsida, Synapsida and Mammalia are old taxa which are traditionally apomorphy-based. Sauropsida, parareptilia and Eureptilia are branch-based. Dinosauria and Aves are node-based. All these forms of definition leaves the odd group out here and there, and keeping tracks of what groups has what type of definition isn't all that easy. Due to this some prefer to scrap all definitions but node-based ones, or apply node-based definitions based on crown groups to all to make things easier. The problem is that reptilia node-based isn't the same as reptilia apomorphy-based.


 * The Wiki-article of bout Reptilia and Amniota (to which it is intimately bound, naturally) are bout clearly apomorphy-based, starting as they do with listing their apomorphies, and citing Laurenti and Haeckel as their auctors. The Amniota you cite isn't Amniota (Haeckel 1866), it's another Amniota (Amniota (Gauthier 1988) perhaps?), and the contents of the two aren't quite the same. Personally I must say I find it rather cheeky to use an old name for a new clade (which is what Gauthier has done), and then go on to say things like "... according to the definition of Amniota, ...", using his own non-standard definition without making that point clear. Particularely interesting is the fact that his definition excludes animals with an amnion from the Amniota. These kind of things are a serious problem with the PhyloCode rules, (unlike their resistance to grades, which is just a matter of taste), because it makes nomenclature unstable. Petter Bøckman (talk) 16:32, 6 May 2009 (UTC)
 * I'm not sure if you're arguing in opposition to phylogentic taxonomy, or simply misunderstanding something. Yes, some old taxa are still widely believed to be based on apomorphies. This is incorrect, however, as nearly all major taxa have long since been given cladistic definitions. Some of those cladistic definitions also include apomorphies (in the cladistic sense), but most don't. Also, just because an article begins by listing characteristics doesn't and shouldn't be implied) to mean a group is defined by those characteristics. A diagnosis is not a definition. Also, under the rules of taxonomy, just because a taxon has been given a definition, doesn't mean the author changes. The author is for the name itself, not any particular definition. If you want to specify a particular definition, it's listed as "Amniota sensu Gauthier". Amniota on its own is still Haeckel no matter what. Haeckel never defined amniota, he diagnosed it. Definitions for clades didn't begin in earnest until the 1980s, and there is still no governing body to determine priority (that's what PhyloCode is for). Yes, the current definition excludes animals with an amnion from Amniota. Dinosauria also excludes all lizards, despite the name ;) The relative merits of one definition over another is a moot point for an encyclopedia, to my knowledge nobody has published an apomorphy-based phylogenetic definition for Amniota, only diagnoses. I've heard the name Apo-Amniota proposed for the apomorphy-based group corresponding to traditional Amniota but I don't think it's been published.
 * Anyway, even if a traditional useage of Amniota based only on diagnosed characters is used, it can't be said that there are non-Sauropodis, non-Synapsid amniotes, because now you're mixing systems--the node and stem based system that governs Synapsida and Sauropsida with the traditional character-based system that you're using for Amniota. If you want to talk about Amniota in the traditional sense, fine (as long as the particular sense is clear in the text), but then don't bring Sauropsida into it, or you'll only confuse things. Dinoguy2 (talk) 21:42, 6 May 2009 (UTC)
 * For the record, I agree that using old names for new clades and completely changing the meaning of well-known taxon names is very far from an ideal situation (just look at the total mess we have with Aves--when PhyloCode goes into effect it will likely be a crown group, leaving things like Ichthyornis as non-avian dinosaurs). But that's the way it is, that's the way almost all researchers have been using these names for the past decade, and that's what should be reflected here since it's majority usage. Dinoguy2 (talk) 21:45, 6 May 2009 (UTC)


 * I'm not arguing in opposition to phylogenetic taxonomy, it clearly has its use and merits. I'm arguing in opposition to the notion that phylogenetic taxonomy is the only valid taxonomy and nomenclature. The argument over what defines versus what categorizes a group is a matter of definition of "definition". The very widespread use of node based definition in amniotes palaeontology does not mean that "some old taxa are still widely believed to be based on apomorphies" is true. In biology these definitions are alive and actively used.


 * Working in a natural history museum, I'm well aware of the use of cladistical methods in research, being a zoologist I'm well aware that despite this Linnaean taxonomy is used by the majority of my colleagues, and as a museum teacher I know it is virtually the only taxonomy used outside academic circles. Using cladistic classification uncommented on Wikipedia like it was the only valid and only used classification is not making Wikipedia better. In the amniote article I tried to make room for bout systems and make clear their differences.


 * The blanket statement that all amniotes are either Synapsids or Saurapsids is only true under a certain subset of definition of the three, and thus that should be made clear. Saying that e.g. Casineria can not have been an amniote as it predates the Synapsid/Sauropsid split is downright ridiculous when just this genus has been suggested as the group that had the first amnions, unless the node-based definition is made clear.


 * There are a few myths in cladistical circles that do not quite conform to reality. One is that cladistic taxonomy is universal, quite a few others can be found in the article pertaining to cladistics. The example used in the clade-article, that Archaeopteryx can not be classed except by using cladistics is a neat example.


 * As for cladistic dinosaur-bird classification, isn't Aves defines as Vulturus + Archaeopteryx, or has that definition been abandoned?


 * BTW, I love your dino-illustrations!Petter Bøckman (talk) 07:46, 7 May 2009 (UTC)
 * Well, if you look at the quote at the top of my userpage, you'll see I agree with you on most points. However I'm not convinced Linnaean taxonomy is still in wide use among amniote workers. Any recent cites that use the Linnaean sense of these names to back it up? The only recent example I know of is Benton's Vert. Paleo. (cited in the Linnaean section of Amniote), but even he doesn't seem to be using an apomorphy sense of Amniota as nothing is basal to Synapsida or Sauropsida. Dinoguy2 (talk) 15:16, 7 May 2009 (UTC)


 * I did look at the quote (actually, it's so good I'm considering nicking it), so I was a bit surprised at our discussion here. I don't know many amniote palaeontologists who use Linnaean (actually, more Romerian) nomenclature (then again, I don't know many vertebrate palaeontologists). The one I know (Jørn Hurum, see Predator X) does. I know a good deal of amniote zoologists who do (I'm a zoologist myself, so that's the group I know best), and it is very widespread in our botanical department.


 * I suppose this only goes to show that the circles you move in shape your perception. I work in a museum, my job is to keep "dead knowledge" alive, little wonder I have such knee-jerk reactions to the PhyloCoode and the changing definitions of the cladisticians. Just so you know it I have nothing against cladistics as such. It is a wonderful tool, the work done on the Lobopodia is a real gem, and the evolution of Sauropoda would never have been understandable without it. Cladistics is a great way of making evolutionary trees, but it is a ratty way of describing and naming groups. Petter Bøckman (talk) 18:48, 7 May 2009 (UTC)
 * That's all well and good, but as I said, it needs to be citable. If there aren't recent peer reviewed sources treating amniotes and sauropsids in a Linnaean sense, it's not appropriate for inclusion here. Whether or not biologists studying living groups use the cladistic sense or not is kind of a moot point, because there are no living, basal amniotes, so this is entirely the domain of vert paleo, which is pretty much 100% cladistic. Implying otherwise would be disingenuous. For extant groups, the definition is used doesn't matter, because the content will be the same either way. I suspect this is why cladistics is popular in paleo and maybe less so for workers studying extant species--the modern guys don't need to worry about what to call "transitional" species, or whether a given species has a given character. A modern biologist can tell if an animal is an apomorphy-amniote by looking at it. A paleontologist would have to wait until some kind of evidence turns up that species x actually had an amnion, which will never happen for almost all fossil species. Dinoguy2 (talk) 19:09, 7 May 2009 (UTC)


 * The description of Casineria published in Nature is a point in question (abstract, I'll post the entire article when I get back to work if you can't access it). The article isn't word-by-word specific about it, but does go on describing how their critter may have been the one to evolve an amnion and thus be the first Amniote, thus indirectly confirming an apomorphy-based definition. Their views are expressed more clearly in the article in Science News Online here. Science News Online isn't peer review as far as i know, but Nature most definitely is, and the article is extremely relevant as far as Amniota goes. Petter Bøckman (talk) 19:32, 7 May 2009 (UTC)

Turtles
While I think that Sauropsida should be presented as a class–a lot of scientists do this and this is the best phylogenetically sound option, more urgently I think note should be made here, and elsewhere, of the theory that turtles, like "euryapsids", are modified diapsids. This theory is all too briefly noted on the Turtle page, and is widely but not completely accepted. The great big tree from the tree of life project gets in the way of presenting this theory, though. I will add notes like this on other "reptile" pages. Innotata 16:51, 19 October 2009 (UTC) —Preceding unsigned comment added by Innotata (talk • contribs)


 * Feel free to ad the relevant information, preferably with sources. Petter Bøckman (talk) 18:55, 20 October 2009 (UTC)


 * There are only a few sources that I can find yet–all from the Turtle page–and it seems I'll need to change this page an awful lot to add anything–and I now have more things to add. Innotata 20:09, 21 October 2009 (UTC) —Preceding unsigned comment added by Innotata (talk • contribs)

Problem
So who can tell me what's wrong with this sentence:

"all existing reptiles, dinosaurs, and birds." —Preceding unsigned comment added by 68.225.137.124 (talk) 00:37, 5 May 2010 (UTC)
 * Well, it's certainly confusingly worded; for one thing, all existing birds are also existing dinosaurs. J. Spencer (talk) 03:29, 5 May 2010 (UTC)
 * Depends on whose definition of Dinosauria one uses, but from a phylogenetic point of view they certainly are. Not everyone is aware of this fact though. I suggest the following: ...is a group of amniotes that includes all existing reptiles and birds and their fossil forefathers, including the dinosaurs, the immediate ancestors of birds. It should cater for all.--Petter Bøckman (talk) 16:44, 5 May 2010 (UTC)
 * I'm agreeable - will you do the honors? J. Spencer (talk) 23:14, 5 May 2010 (UTC)
 * Gladly!--Petter Bøckman (talk) 06:06, 6 May 2010 (UTC)

Sauropsida is being listed on all the wrong articles
Okay. As someone has mentioned waay up there, Sauropsida is not a class. Yet, there are bunches of articles about dinosaurs and many other reptiles that have the class listed as Sauropsida. The proper name is Reptilia, not Sauropsida. --TangoFett (talk) 06:05, 27 January 2011 (UTC)
 * The new automatic taxobox will hopefully help sort this out, but it will take some time to implement across all pages. This can be changed on an individual basis in the mean time. MMartyniuk (talk) 07:08, 27 January 2011 (UTC)

The meaning of "Synapsids"
Just to avert an edit war:

The term "synapsids" have two distinct, but closely related meanings: As a grade and as a clade. In this article, discussing a name from phylogenetic nomenclature, it is tempting to see it as the latter. Thus, whether I mean one or the other, I need to specify. For the clade, I suppose "the synapsid line" will suffice. For the grade however, I am left with several sub-optimal alternatives: reptile-grade synapsids, mammal-like reptiles, class Synapsida and stem synapsids. The first one is easily understandable and cater to those using "synapsids" as a clade. The second one is antiquated and vernacular, but has a very clear and stable meaning. The class really require an intimate knowledge of the use of the term in it's many forms, and the last one require the reader to know the crown-, stem-, total group concepts. Non of them are ideal. I'd would like some feedback on just which term serves us best here. Petter Bøckman (talk) 19:53, 13 November 2011 (UTC)
 * What about non-mammalian synapsids? And since it needs to be verifiable, how do the sources you're drawing from phrase it? It's not our place to decide which is most clear, just to use the terms a majority of sources do. The line in question is "Goodrich's classification thus differs somewhat from Huxley's, in which the reptilian-grade synapsids known at the time (mainly Dicynodon) would have fallen under the sauropsids." Where are you getting this from, and how does that source put it? Or is this an original conclusion drawn from a primary reading of the material? If the latter it probably shouldn't be included. MMartyniuk (talk) 20:38, 13 November 2011 (UTC)
 * It's from Goodrich, 1916. He wrote: [Huxley] failed at the time (Huxley, 1871) to appreciate the fact that his group Sauropsida included forms like Dicynodontia and the Sauropterygia, which belong in all probability to the Mammalian line. I'll source the article text at once. Petter Bøckman (talk) 22:50, 13 November 2011 (UTC)
 * Since the source uses the term "mammalian line", that's what we should use. MMartyniuk (talk) 13:28, 14 November 2011 (UTC)

"Non-avian dinosaur": a bit of advice.
The phrase "non-avian" before "dinosaur" was recently deleted by someone who (like me) considers that the vernacular "dinosaur" does not encompass birds and that it is pointless to try to change common use so that birds are referred to as dinosaurs&mdash;pointless even if the attempt is successful. I suggest that deleting "non-avian" is not a useful strategy. Many published works add the redundant qualifier "non-avian" just to avoid controversy, and there can be no objection to doing the same on Wikipedia.

The three points that do need to be made, over and over again, are as follows: Those who oppose paraphyly even in vernacular use and wish to comment will please start a new subsection. (They might also explain why they have not been fighting the vernacular use of "lizard".) This post is directed to the pro-paraphyly editors, and I welcome their comments in this section. Peter Brown (talk) 20:06, 3 September 2013 (UTC)
 * The fact that someone uses "non-avian dinosaurs", in Wikipedia or elsewhere, involves a minor redundancy that does commit the writer to the view that birds are dinosaurs.
 * When the term "dinosaur" is used in the professional literature, it is normally assumed that the reader will not consider that the term covers birds. A writer who really means to include the entire clade has to counter that assumption by writing "dinosaurs including birds" or by some equivalent means. Most scientists, like everyone else, do not include birds among dinosaurs unless instructed to. Thus, The Paleontological Society can publish a 2011 paper entitled "The First Hatchling Dinosaur Reported from the Eastern United States" &#8203; without the absurd implication that no one had reported bird hatchlings from this area prior to that year.
 * Even among professionals, there is no consensus as to whether paraphyletic taxa should be formally recognized. To foist an anti-paraphyletic POV on the public with the claim that it is more "scientific" although the scientists themselves are divided is dishonest. And the only objection to excluding birds from dinosaurs is that it renders the latter group paraphyletic.

A word from the opposition
To briefly address point 2 above, a Google Scholar search for "non-avian" returns over 4,000 results over the last 10 years. I understand the argument that it's cumbersome and not always necessary given context, but let's not pretend it isn't near-universally used in the modern technical literature, a few counter-examples aside (that I suspect were committed by researchers who either genuinely don't care/think the context is clear, were sloppy with wording, etc., rather than genuinely don't consider birds a dinosaurian sub-group). I agree non-avian dinosaur is a terrible and clunky phrase (waiting patiently for "stem-bird" to catch on, which I should point out was invented by PhyloCodists for a paraphyletic group!), but if we're being both verifiable and precise, it's the one that should be used. If we use it at all. Not sure why every example related to extinct reptiles always has to be dinosaurs, or even why single specific examples are needed at all. If you say "extinct reptile group" dinosaurs are the first thing people think of. To address point three, paraphyly isn't the only or even the biggest problem. The biggest problem with removing birds from dinosaurs taxonomically is that there are about 30 different defensible options regarding where to draw that line. It throws the entire taxonomic unit into anarchy (which may be why monophyly's biggest supporters are all dinosaur paleontologists...) MMartyniuk (talk) 21:04, 3 September 2013 (UTC)


 * Unfortunately, Google Scholar provides no way of determining how important that 4,000 number is. Now, if we could tell how many times "non-avian" might intelligibly have been used but wasn't, we'd have some statistics we could reasonably compare. I'm not pretending that the phrase isn't near-universally used; I honestly believe that there are a host of exceptions and that they don't indicate sloppiness or lack of interest.


 * Try to find cases where an author clearly uses "dinosaur" to mean the whole clade without stating explicitly that he or she is including birds. Yes, there are a few, but they really are hard to find. I take this difficulty as evidence for my statement, "Most scientists, like everyone else, do not include birds among dinosaurs unless instructed to."


 * In popular writing, a rejection of paraphyly (though without using the term) seems to be the most common reason for including birds as dinosaurs. I freely grant that excluding Avialae or whatever from Dinosauria poses difficulties for systematics, and I'm not suggesting that this be done in the technical literature. Sure, include Passer in Dinosauria if that's convenient, just don't insist that the layperson regard sparrows as dinosaurs. Peter Brown (talk) 22:18, 3 September 2013 (UTC)


 * Martin's current edit omits the whole problem and is a good solution in my view. Petter Bøckman (talk) 13:12, 4 September 2013 (UTC)


 * All the same, my original point stands. With some exceptions that I consider significant, as when peer reviewers allow "non-avian" to be omitted from journal-article titles, "non-avian dinosaur" is commonly used both by writers who think that the phrase is mildly redundant and among writers who consider it nothing of the kind. There is no telling how many of Matt's Google Scholar hits reflect one view rather than the other. Use of the phrase in Wikipedia, which accords with frequent use in the professional literature, is unobjectionable; the qualifier "non-avian" should not be deleted.


 * Bear in mind that Owen introduced "Dinosauria" and "dinosaur" to two different audiences: "Dinosauria" to the intelligentsia in the British Association for the Advancement of Science and "dinosaur" in his popular lectures. Though the words were synonymous when introduced, the semantic futures of these words&mdash;what they came to mean&mdash;were crucially dependent on the diverse influences that came to bear on these two words as they operated in different communities. Today, they differ both in meaning and in scope. Sparrows are in Dinosauria but they are not dinosaurs.


 * Peter Brown (talk) 21:57, 4 September 2013 (UTC)
 * Good points, and let's remember that realistically, and in practical usage, the vernacular "dinosaur" does NOT refer to the taxon Dinosauria, but to any giant extinct reptiles. Try as scientists might to change popular usage, this vernacular term exists. It may be time for professionals to start drawing a hard distinction between "dinosaur" and "dinosaurian", or to de-emphasize use of this totally arbitrary and now very confusing assortment of bird-line archosaurs altogether As I've written before here . MMartyniuk (talk) 11:38, 5 September 2013 (UTC)


 * They would have surely been dinosaurs when the extinction occurred. When speaking of the evolution of avians, referring to them as dinosaurs seems absolutely necessary. In colloquial speech I think it's too much to try to save "dinosaur" but if we're discussing evolution, they came from dinosaurs, are still dinosaurs and will always be dinosaurs.


 * The word "dinosaur" in ordinary nonscientific usage does not include birds. It is similar to "great ape", "ape" and "animal " in nonscientific usage excluding humans. 99.101.56.68 (talk) 18:23, 13 November 2022 (UTC)

Link to Sauria
As it stands, the taxobox in this article contains a wrong link: Sauria, which currently redirects to Lizard. Reading the lizard page, there have been three different proposals for the name 'Sauria'; I presume that the link from here was intending one of the recent proposed meanings, rather than the established one.

I have no desire to get into disputes about taxonomy, but as it stands that link is wrong and useless: the text says "all living reptiles and birds", but it takes you to Lizard. I was tempted to change it, but I'm not sure what to change it to: I suspect reptiliomorpha, but I'm not sure. --ColinFine (talk) 13:20, 28 December 2013 (UTC)


 * You are quite right Colin, I see Dinoguy beat me to finding a solution. I think his solution is about as good as we'll get it, though I would ideally like to see birds in the taxobox here. I guess I'll have to settle for the mallard in the picture. Petter Bøckman (talk) 21:17, 28 December 2013 (UTC)

Cladogram
Why does the cladogram so faithfully reproduce the Tree of Life hierarchy when the text of the article clearly refutes its placement of turtles? &mdash;Gordon P. Hemsley&rarr; &#x2709; 01:38, 24 October 2014 (UTC)

Probably because the placement of turtles is very controversial. Depending on you talk to they are either true anapsids or lapsid diapsids (ie they lost the second hole). Morphology suggests the former and the molecules suggest the latter. It's really quite confusing.


 * I think there are three or four published positions for turtles, and no real consensus in sight. Petter Bøckman (talk) 21:31, 25 November 2014 (UTC)

Reptilia, Aves
I realise others have alluded to the issue of mixing clades with traditional classes, but at the moment the automatic taxobox is showing the Class is Reptilia. Can this be edited to show the class as "Reptilia, Aves" or "Reptilia and Aves"? (I can't work out how to edit the taxobox...)Ordinary Person (talk) 09:09, 8 April 2015 (UTC)
 * Aves is a subgroup of Sauropsida, not one possible parent group... Dinoguy2 (talk) 11:44, 8 April 2015 (UTC)

Bird classification.
First of all, if theropods are a suborder, and penguins are an order, then Birds should be classified as a class. Two, orders cannot occupy classes. Three, the bird classification within Dinosauria is heavily inconsistent. — Preceding unsigned comment added by 68.117.14.169 (talk) 01:13, 19 October 2015 (UTC)


 * The reason I just reverted your sidebar edits is because your edits do not reflect the content of the article - specifically the cladogram. I would suggest first editing the content of the article (including the proper citations), then nobody would object to the sidebar being edited (though they may object to the changes to the article). But if you keep editing the sidebar to something that doesn't reflect the content of the article, you should expect your edits to continue being reverted. --holizz (talk) 01:41, 21 October 2015 (UTC)

Taxobox
The taxobox currently lists Reptilia and Aves as two separate subgroups and excludes the latter from clade Romeriida, which is incorrect. Someone had already corrected this, but that edit was reverted by someone who claimed the taxobox needed to explicitly acknowledge the inclusion of birds in Sauropsida, but this already mentioned in the text (in the first sentence) and the cladograms, and illustrated by the first image.Kiwi Rex (talk) 18:35, 31 October 2019 (UTC)

Introduction
In the introduction, we have: Sauropsida ("lizard faces") is a taxonomic clade that consists of reptiles (which includes birds) and the extinct Parareptilia. The sentence as written implies that reptiles naturally (and possibly always) includes birds; however, the inclusion of birds within reptiles is a matter of context. I've made a small edit that allows for this nuance: Sauropsida ("lizard faces") is a taxonomic clade that consists of reptiles (including birds) and the extinct Parareptilia.

We also have: Sauropsids are the sister taxon to synapsids (often mistakenly referred to as "mammal-like reptiles", as synapsids are not reptiles), some of which later evolved into mammals. As I read it, the clause "as synapsids are not reptiles" is intended to explain the error of the commonly-made equivalence (that synapsids are mammal-like reptiles); unfortunately, however, the syntax conveys basic support for a reference to be made, which, since the reference is explicitly described as erroneous, is nonsensical. More succinctly, the natural link of as in the second clause is to referred, and not to mistakenly as the writer no doubt intends. My suggestion is something along the lines of: Sauropsids are the sister taxon to synapsids—often mistakenly referred to as "mammal-like reptiles," although synapsids are not reptiles—some of which later evolved into mammals. I expect there are more elegant ways it can be said, but the original, if read carefully, is absurd. Aboctok (talk) 19:15, 16 July 2020 (UTC)

Wiki Education assignment: Physiological Ecology of Animals
— Assignment last updated by Rico.schultz (talk) 20:56, 26 March 2023 (UTC)

Excretion of Nitrogenous Waste
A pretty fundamental difference between mammals and reptiles is that (all?) mammals excrete nitrogenous in the form of urea, and (all?) reptiles and birds excrete it as uric acid (saving a lot of water at a small cost in energy (birdshit is much more concentrated than urine!)). Is it known at what point in the evolution of tetrapods, sauropsids and synapsids this happened? If so it would be great if someone could generate an article, reference, or explanation. [Is the method of excreting nitrogenous waste even a key difference between sauropsids and synapsids??]. GlidermanGliderman (talk) 14:36, 19 April 2023 (UTC)