Talk:Vertebrate/Archive 1

Archive 1

Agnatha

Shouldn't we be able to access Agnatha(fishes) from this page, since it is the superclass under Vertebrata? I looked around, and I could only access Agnatha from its own article page (correct me if I'm wrong). So on the table to the right, I think it should include Agnatha superclass under the 'typical classes'... Buzoo 10:30, 9 Feb 2004 (UTC)

Agnatha is not a proper superclass. It is paraphyletic.--Dustin Asby 20:36, 13 of 2005

My Biology Textbook lists it as a proper subclass...

Taxonomic Confusion

I was wondering: If veretebrata is a subphylum, what is craniata?--Dustin Asby 20:36, 18 October 2005 (UTC)

It's an unofficial grouping of animals with skulls. --M1ss1ontomars2k4 | T | C | @ 04:09, 16 May 2006 (UTC)

Odd phrase

"Vertebrates strted to evolve about 530 million years ago ..." the article states. So before that we just sat around passing the time? Jimp 01:33, 8 March 2006 (UTC)

Well no, most mammals weren't even around at this time so i dont think you were just sitting around waiting for time to pass, the forms of life around at that time had other means of movement, so they didnt just sit around all day.

Taxonomy

The list of classes should be better organized.

It's organized roughly in evolutionary order, with indents indicating line of descent... do you have anything specific to suggest?Dinoguy2 02:58, 21 April 2006 (UTC)

Lamprey taxon?

The lamprey page lists them as class Cephalaspidomorphi, while this page lists numerous lamprey classes under Hyperoartia. As I know next to nothing about lamprey, could someone please standardize this? It's very confusing when different pages use different taxonomies :) Dinoguy2 14:29, 25 April 2006 (UTC)

Although I made the change to Hyperoartia, I must agree that it's somewhat confusing. Part of the blame lies with my formatting. Listing "Hyperoartia (lampreys)" right after the bullet, with no rank, may suggest to some that the classes and orders listed below it are all types of lampreys. However, this was not my intent; if the groups below it were subsets of Hyperoartia, their bullets would be indented farther in. Instead, the groups listed below it (Conodonta, Thelodonti, etc.) are different groups of jawless fish that are not lampreys. I'll think of a clearer way to type that line, but the recent classifications I've seen do not assign Hyperoartia a Linnean rank.

The article for Cephalaspidomorphi provides some explanation why different authors disagree about where to classify lampreys. Essentially, Hyperoartia includes lampreys with certainty because it's defined to include them. By contrast, Cephalaspidomorphi is anchored on a group of fossil jawless fish that may or may not be close relatives of lampreys. So Hyperoartia may be a subgroup of Cephalaspidomorphi, or it may be unrelated, as Mr. Janvier argues on the Tree of Life site.

I agree that we should make the classification as uniform as possible among articles, but we shoudln't try to obscure that there are arguments out there for more than one classification. I don't want to remove all reference to Cephalaspidomorphi on the lamprey pages, but will include Hyperartia in the hierarchy and list it as a possible subgroup of the cephalaspidomorphs.

Cephal-odd 07:32, 26 April 2006 (UTC)

Ah, I see. I had checked the lamprey page and could not find any mention of Hyperartia in the taxonomy section, which is what threw me. If Hyperartia were listed as unranked somewhere in the Lamprey taxobox, or Cephalaspidomorphi included on this page as a sub-bullet of Hyperatia, it would help enourmously.Dinoguy2 13:36, 26 April 2006 (UTC)

Over Precision

The openning paragraph quotes the number of vertebrates as "about 57,739 species". That doesn't seem much like an approximation to me. I know that most people agree the only additions to most families will be from arguments over species and subspecies, but there is still room for expansion; fish in particular seem to be found at a rate of a few species a year. I'm not an expert in the area, but I think 57,739 is far too precise a number. I'd change it, but I thought it might be a good idea to leave that to someone who knows more about what they're talking about. Morgrim 09:40, 21 September 2006 (UTC)

Vandalism

This page has been subject to alot of vandalism i suggest that somone put a lock on this page to solve this problem.Fheo 22:24, 16 October 2007 (UTC)

looks like someone likes to keep taking tetrapods out of lobed fishes... probably creationists —Preceding unsigned comment added by 76.189.206.11 (talk) 15:42, 28 December 2007 (UTC)

Creationists? Tetrapod chauvinists! I'll try to fix it. Innotata 22:57, 25 October 2009 (UTC) —Preceding unsigned comment added by Innotata (talk • contribs)

Classification chaos

There are some serious problems with the classification section and I think I need some help. Until just now the allegedly phylogenetic listing classed tetrapods as sister to lobefin fishes and it still classes Gnathostomata alongside some taxa of a rather lower rank. I just revised the lobefin/tetrapod part and changed, for example, "formal" to conventional classification (what does a formal classification look like? Does it wear a suit-coat?), but the way it is remains unsatisfactory. All that "unranked groups" and "sometimes this" stuff etc. will probably confuse a lot of people but I can't think of any thing else. Since this page is refers to a major animal group this is urgent. I also am worried that some people — creationists as claimed above perhaps, the sort of "chauvinists" I half-jokingly referred to, the sort of people trying to project their conservative opinions on biological classification who turned Flamingo into an editorial, well-intentioned people I suspect caused all the old problems by trying to make all the Superclasses fit into the next ranks, vandals, etc. Can editing this page be restricted? Can somebody help fix this? --Innotata 20:58, 26 October 2009 (UTC) —Preceding unsigned comment added by Innotata (talk • contribs)

Whoops I left out that I think the people listed above might mess things up! --Innotata 21:37, 26 October 2009 (UTC) —Preceding unsigned comment added by Innotata (talk • contribs)

Why are there ranks like class used in the Phylogenetic classification section at all? Phylogenetic classification is rankless practically by definition... As far as I can see, the page currently contains two traditional classifications: one simple, one detailed and mistakenly labeled as a phylogeny. Those sections should be merged, and an actuall phylogeny added, with a graphical cladogram like this [1] Dinoguy2 (talk) 23:08, 26 October 2009 (UTC)

Good point. Personally I believe that the Linnaean system is compatible with phylogeny (see Aves: Taxonomy in Flux at [2] for an example of a very speculative taxonomy based on genetic studies), but right now things are completely unsettled in systematics. If the tree on here were to actually look like that for therizinosaurs it would be rather wide, though! So what to do here, I don't know. Also: I sure got carried away above! Innotata 14:24, 27 October 2009 (UTC)

I agree that Linnaean taxonomy isn't necessarily incompatible with PN, but the hybrid of the two is something else altogether, Evolutionary Taxonomy, and you'd be hard-pressed to find a single citeable source that uses such a thing from the last 40 years or so. The only one i know of is here, and it only covers vertebrates. As for the sprawl issue, the best thing to do would be to simplify the tree down as much as possible and end on very high "ranks", leaving further detail to the sub-pages. I may take a crack at this and see how it turns out. Dinoguy2 (talk) 16:12, 27 October 2009 (UTC)

Ok, I put up a cladogram based on the TOL project, though I'm not sure how up to date it is. Dinoguy2 (talk) 16:54, 27 October 2009 (UTC)

This still needs improvement. You need to explain phylogeny better, in my opinion: phylogeny and Linnaean taxonomy are widely recognized as potentially compatible. Phylogeny obviously does use morphology, and at least in bird phylogenies the best supported clades genetically have some morphological characters. Also, Dipnoi is usually considered to be close to Tetrapoda, and the classification of the prehistoric fishes needs checking. Still, it is an improvement. Thanks, Innotata 17:45, 27 October 2009 (UTC) —Preceding unsigned comment added by Innotata (talk • contribs)

Well, like I said I took the actual phylogeny from the TOL project, which is dated to 1997, over a decade ago, so if somebody has a more up-to-date cladogram we should certainly use it. If there's a source explicitly combining Linnaean and phylogenrtic taxonomy, we can use that, but I don't have much lit in this area. Dinoguy2 (talk) 19:30, 27 October 2009 (UTC)

I've taken a step in clearing this up by mentioning evolutionary taxonomy. But really, the ranked taxonomy in the article is already evolutionary. A non-evolutionary taxonmy could include such things as class Pisces, etc., and group like characters together without regard for relationships. Strictly speaking, nobody has used non-evolutionary taxonomy since at least the mid-20th century. Dinoguy2 (talk) 19:35, 27 October 2009 (UTC)

The phylogeny looks pretty good. The main thing I would change is that Tetrapodomorpha usually refers to the total group of Tetrapoda, so it should include the rhizodonts and osteolepids from the tetrapod stem group. That node is labeled "terrestrial vertebrates" on the TOLweb. That site calls that clade Stegocephalia, but most people call it Tetrapoda.

Also, relationships among some of the fossil fish taxa are contentious, so we may want to simplify the phylogeny to show a consensus of different views. Cheers, Cephal-odd (talk) 21:37, 27 October 2009 (UTC)

I've reverted the name change--whether or not you would change it, it's not what the source uses so changing it is original research. Various people use various definitions of tetrapoda (include, exclusive, apomorphy-based, etc.) and until PhyloCode comes out, all are equally valid anyway. The authors of Tiktalik, for example, classify it as a basal tetrapodomorph outside Tetrapoda proper. Dinoguy2 (talk) 17:43, 28 October 2009 (UTC)

You're right that the TOLweb page doesn't call that node Tetrapoda, but they don't call it Tetrapodomorpha either. Tetrapodomorpha is usually applied to the node that includes osteolepiformes and rhizodonts, such as here or in the literature here. Basically it's the total group of tetrapods and the sister group of lungfishes. We could follow the convention used by Laurin et al. on TOLweb, but then we should call that node Stegocephalia.

As you point out, specialists disagree about what node to call Tetrapoda. Some have argued against applying the name to the crown group, and there are several publications supporting a definition based on limbs with digits, not least because reconstructions of phylogeny have been too unstable to be sure what falls into the crown group. This opinion has been published several times, so it shouldn't qualify as original research, although it should be referenced.

Although it's close to tetrapods, I think Tiktaalik would be a non-tetrapod under the apomorphy-based defintion as well, given its fins. Presumably it would fit in among the (paraphyletic) osteolepids in the phylogeny that appears in this article.

Cephal-odd (talk) 20:50, 28 October 2009 (UTC)

Tetrapoda, I should note, is the older name. Also, this really looks like a tree of fish! Shouldn't this be on the fish page instead? The description of taxonomy is good for now in my opinion, but I'll get back to it later. I don't know what all this talk on the incompatibility of the prohibition of certain polyphyly and Linnaean taxonomy on Wikipedia is about. It seems to be highly exaggerated and not necessarily neutral. I'll try to find a source "explicitly combining Linnaean and phylogenetic taxonomy", and expect to find one: but do you really want this to say things like "Class Dipnoi"? Innotata 22:16, 27 October 2009 (UTC) —Preceding unsigned comment added by Innotata (talk • contribs)

"Fish" isn't a taxon, it's a descriptive form synonymous with 'basic vertebrate'. We are, after all, slightly modified lobe-finned fishes... There's no prohibition on combing Linnaean taxonomy et.c, it's just that most scientists no longer use it. If you can dig up a source that's fine, but altering the cladogram to make our own evolutionary taxonomies is original research, which is prohibited. If the source places Tetrapodomorpha where it is, that's where it goes. To do otherwise is editorializing. If it's not the current consensus, find a different tree from a different source. Dinoguy2 (talk) 03:57, 28 October 2009 (UTC)

What I meant by a tree of fish is that it looks rather similar to what is on the fish page already. How it is now is quite good and I won't change it except as noted below unless I come across something worthwhile and new. I think this might exclude some obscure fossil fish and I'll check this to be sure. I also will add extinct tags. (I can understand why you forgot this, being a "dino guy"). If you think (extinct) looks better than † go ahead and alter this. I'll also check if any of the red-linked clades are listed under a different name. I also think that most scientists do use Linnæan taxonomy. Innotata 16:17, 28 October 2009 (UTC) —Preceding unsigned comment added by Innotata (talk • contribs) I just saw the tree of life page and it puts this classification on a weaker foundation than shown here as fsr as I can tell. Thanks for putting up the tree and for all the input nonetheless; Innotata 16:29, 28 October 2009 (UTC)

I'd recommend against adding anything to the current tree, as it is as complete as the cited source provided. We're reporters here, not researchers, and creating our own, non-verifiable supertree or synthesis of obscure fossil fish is not a very encyclopeadic thing to do. If a more complete tree can be found in a book or in the literature, we'll use that and completely discard the current one. Dinoguy2 (talk) 17:46, 28 October 2009 (UTC)

Shouldn't the hagfish be in the cladogram too? Petter Bøckman (talk) 09:39, 29 October 2009 (UTC)

Ask Janvier 1997. IIRC this cladogram was published before several recent studies finding a monophyletic Agnatha. Janvier et al. find hagfish to be non-vertebrate craniates. That is, they fall just outside vertebrata proper. Dinoguy2 (talk) 16:01, 29 October 2009 (UTC)

I'd just like to be done with this now, and I guess I agree that the tree should be left alone, though I think certain popular books show a more up to date tree than this, though with very few sources. I'd like to explain the taxonomy better, but I can't think of anything to put on here. Sorry for all the confusing remarks made above. Innotata 16:14, 29 October 2009 (UTC) —Preceding unsigned comment added by Innotata (talk • contribs)

Since we're citing the Tree of Life web, I'll label the tetrapod node "Terrestrial Vertebrates as they do here, and provide wikilinks to Stegocephalia and Tetrapoda. Stegocephalia is the name used by Laurin in TOLweb, and Wikipedia's tetrapod article discusses basically the same taxon rather than crown tetrapods specifically. With luck this will be a suitable compromise.

Cheers,Cephal-odd (talk) 23:28, 31 October 2009 (UTC)

I think using Stegocephalia (despite Laurins use) is unfortunate, as the name was coined to descrine a grade, and is still in use as such. I suppose Laurins use is meant as sort of a cladistic in-joke. Abandoning the very commonly used apomorphy-based Tetrapoda (an expression always used to denote the clade) in favour of Stegocephalia only gives meaning to the in-crowd. Even though I started the Stegocephalia page and would like links to it, I don't think this use is appropriate for a public encylopedia. Petter Bøckman (talk) 09:52, 1 November 2009 (UTC)

I'm inclined to agree that Stegocephalia as used this way is an obscure name that departs considerably from its traditional usage in the literature. Advocates of that usage would probably say that that particular clade isn't especially important, and that crown Tetrapoda is a more relevant clade to most biologists. But this thread seems to be predicated on following the usage on the TOLweb site, at least until we find another source. Cheers,Cephal-odd (talk) 21:58, 16 November 2009 (UTC)

Re: Hagfish: Even though the hagfish have been in and out of vertebrata a bit, I feel it should be included in the tree, and marked with a comment to the effect that it's status as vertebrate is under dispute. Petter Bøckman (talk) 10:49, 30 October 2009 (UTC)

I agree about the hagfish, and the Tetrapoda. How did Janvier et al & Laurin decide what defines Tetrapoda and Vertebrata. I think that you should stop calling tetrapods or stegocephalians "terrestrial vertebrates." This shows you haven't seen a terrestrial fish (e.g., a swampeel or a walking gourami). I can't really think of anything else though. Also: if you want to see a Wikipedia supertree, click here innotata (Talk | Contribs) 19:50, 9 November 2009 (UTC)

I (or we) are not calling terrestrial vertebrates anything. The source is. Deal or find a different source ;) Anyway, it's not saying "all" terrestrial vertebrates, and not all tetrapods are even terrestrial. It's just a descriptor, not a diagnosis. Placoderms aren't the only armored fishes either. Dinoguy2 (talk) 20:15, 9 November 2009 (UTC)

I don't see any trees at all on that passerine page. I think you're confusing a cladogram with a taxonomy. Dinoguy2 (talk) 20:12, 9 November 2009 (UTC)

I shouldn't leave this page with red links: climbing gourami & swamp eel innotata (Talk | Contribs) 19:53, 9 November 2009 (UTC)

Dinoguy2: Deal or find a different source. Would it be a posibility to ad things from other sources, as long as it is clearly marked as such? Petter Bøckman (talk) 01:23, 10 November 2009 (UTC)

I don't think so. "Articles may not contain any new analysis or synthesis of published material that serves to advance a position not clearly advanced by the sources." [3] On a taxonomy this is probably ok, as long as each line is sourced. A cladogram, however, is not a diagram or taxonomy as much as the mathematical outcome of an analysis. Adding things to it mislead the reader, because had these things been in the original, the entire structure of the cladogram would likely be different. A synthetic cladogram is a supertree, and even those don't simply slap various trees together, but mesh the original raw data together to arrive at a consensus result. Dinoguy2 (talk) 01:30, 10 November 2009 (UTC)

Hm, that leaves us in a difficult situation as far as cladograms goes, as there are probably not to identical takes on anything, at least not yet. Publishing a cladogram under this regime means taking side for one author over another, and may thus bring us into conflict with neutrality. Not a good situation at all. Petter Bøckman (talk) 07:05, 10 November 2009 (UTC)

Why not post two conflicting cladograms and explain the differences? If the field is that unresolved, posting any kind of taxonomy by itself is very misleading to the reader. Apparently, we really have no clue how these things are related. So why pretend there's consensus? Dinoguy2 (talk) 17:52, 10 November 2009 (UTC)

There's not that much a question of phylogeny, rather of nomenclature.Petter Bøckman (talk) 10:11, 11 November 2009 (UTC)

As far as passerine is concerned, see the talk pageinnotata (Talk | Contribs) 19:21, 11 November 2009 (UTC)

I should have clarified the above comment. The point is that despite the supposedly old-style-taxonomic nature of passerine and similar bird pages, the detailed clades are in effect a tree, and requests and guidelines for what could be called synthesis on the part of editors are on the talk page. As for the name of the Tetrapoda (or whatever), why not use the best descriptive term that exists, rather than a formal or informal clade name? The pont about the swamp-eels was that not only are tetrapods as important in nonterrestrial habitats as in terrestrial ones, but that in much of the world non-vertebrates are common and important in terrestrial habitats <font: Monial>[[User:Innotata|''innotata'']]<font> <small>([[User_talk:Innotata|Talk]] &#124 [[Special:Contributions/Innotata|Contribs]])</small> (talk) 20:42, 11 November 2009 (UTC)

Whether or not original synthesis like that is ok is a matter of debate. But if it's a cladogram, it's a specific diagram reproduced from a scientific study. To change anything in the diagram is to change the data which produced that arrangement (no actual data goes into arranging a taxonomy, especially a ranked one. It's an art, not a science). Changing scientific diagrams to include data not included by their author is to falsely attribute findings to the study that produced it, and frankly, looks very unprofessional as it could imply that we don't even know what cladograms are, how they work, or why it's highly problematic to arbitrarily change them around.

As for nomenclature, if it differs than anything we do except list common names is taking sides. That's the nature of the beast until PhyloCode is published. We should just use whatever the most comprehensive studies are or most recent. If you'd like to change the content of the cladogram, go ahead, but I'm putting an OR tag at the top of the article. Dinoguy2 (talk) 00:12, 12 November 2009 (UTC)

If we are reproducing a cladogram from a specific study, then I agree that we shouldn't change it. But the heading is "phylogenetic relationships" rather than "cladogram", which affords much more flexibility. A cladogram is one way to represent a group's phylogeny, but efforts to show phylogeny go back almost a century before Hennig. Many secondary sources use phylograms, such as this one, that are the accumulation of many studies, without citing any one analysis.

I agree with you that it's important to fairly represent the strong phylogenetic hypotheses without privileging one over another. But there's nothing misleading about, for example, drawing a consensus phylogeny that summarizes nodes that specialists agree on. For instance, if two studies disagree whether a phylogeny should be

• A (B (C + D))

or

• A ((B + C) D))

Then it would be reasonable to depict a consensus phylogeny as

• A (B + C + D)

and show an unresolved trichotomy where disagreement still lies. An example would be something like this figure from a Nature paper, where myriapods may be related more to chelicerates, or more to the crustacean-insect clade, but are obviously related to both in a more general way.

Another reason to adapt a phylogenetic tree is to use wording that matches Wikipedia's usage in other articles, so as not to confuse the readers. For instance, some names (such as "terrestrial vertebrates") don't match Wikipedia's articles about those clades (Stegocephalia and Tetrapoda). One advantage of having so many biologically informed editors is that we can draw a diagram that summarizes what biologists know, while pointing out where they disagree.

In conclusion, I think a group's phylogeny doesn't "belong" to anyone in particular, and needn't be a report of one particular study out of many. The important thing is to be clear, both in the information we show and in stating our sources. Cheers, Cephal-odd (talk) 21:58, 16 November 2009 (UTC)

I quite agree with Cephal-odd here, not at least for the sake of usability. The sourcing for the cladogram says "based on" anyway, which to me indicate that we have a bit of a leeway. As for naming, I cant say I see how changing Laurins "Stegocephalia" to e.g. "Tetrapodes (in the orogiginal cldogram termed Stegocephalia)" will in any way invalidate the tree, nor Laurins work. Petter Bøckman (talk) 05:37, 17 November 2009 (UTC)

I agree about craniates being included, but the ambiguous classification of a single group shouldn't be in the introduction. It needs its own section if it's to be included. Ekulio (talk) 14:53, 8 September 2011 (UTC)

I think a separate section is a good idea. Mentioning that something to the effect of "hagfish are sometimes included, depending on author" in the lede is probably enough. Petter Bøckman (talk) 18:10, 8 September 2011 (UTC)

Bony fish

Our lede says vertebrates include "bony fish", which I take to mean all fish that have bones, but the link seems to be to a grouping that is smaller than that. Is this meant, or can we fix it? DJ Clayworth (talk) 22:39, 12 March 2010 (UTC)

Bony fish redirects to Osteichthyes, which is correct. With ~30.000 different species, this superclass alone includes more than 95% of all fishes. Disregarding long-extinct groups only known from fossils, the only groups beyond the Osteichthyes are the cartilaginous fishes (~1.000 extant species), lampreys (<50 extant species) and hagfishes (50+ extant species). • Rabo³ • 23:03, 12 March 2010 (UTC)

The term "bony fish" is the vernacular name for the class Osteichthyes (it is also where the link goes). Their hallmark is having ossified (or bony) skeleton contrary to the cartilaginous fishes (sharks & rays) who have cartilaginous skeletons. One could exchange all the names in the lede with their scientific counterparts, but I feel it is better using the vernacular names. Petter Bøckman (talk) 23:04, 12 March 2010 (UTC)

My mistake. I didn't realise (and it's not clear from the article) that Osteichthyes included all the fish with bones. Another reader had a similar issue. I'll suggest a slight modification at Osteichthyes. DJ Clayworth (talk) 13:24, 13 March 2010 (UTC)

All fish are vertebrates, not just the bony fish. The Mysterious El Willstro (talk) 04:33, 14 August 2010 (UTC)

Hagfish aren't - they lack vertebrae entirely, though whether this is their primitive state or a secondary loss is unclear. Mokele (talk) 13:27, 14 August 2010 (UTC)

Teleostomi

Please see Template talk:Taxonomy/Teleostomi#Skipping Eugnathostomata where we are discussing how to handle the display of Eugnathostomata in the automatic taxobox. Bob the WikipediaN ^{(talk • contribs)} 01:32, 24 April 2012 (UTC)

Pronunciation

Dumb question, but is 'vertebrate' ever pronounced in the biological Latin way as 'vertebratee' or 'vertebratees'? Drf5n (talk) 18:36, 26 April 2012 (UTC)

In other languages, yes. Vertebrata (the Latin form) is of course often pronounced according to Latin pronunciation rules. Petter Bøckman (talk) 09:39, 27 April 2012 (UTC)

Relevance of gills?

Why are gills discussed in such detail in this article? I suggest this section should be deleted or moved to a more appropriate article.__DrChrissy (talk) 10:53, 12 May 2014 (UTC)

New lead image

Examples of major classes of vertebrates. Clockwise starting top left: Class Agnatha (jawless fishes), Class Chondrichthyes (cartilaginous fishes), Class Osteichthyes (bony fishes), Class Amphibia (amphibians), Class Reptilia (reptiles), Class Aves (birds) and central image, Class Mammalia (mammals)

I am proposing this new lead image as it covers all 7 of the classes of vertebrates - the current image contains examples of only 5 of the classes.

That's a good idea. Perhaps we could see if we can improve some of the component images. How many classes there are depends on the viewpoint. Bony fish are sometimes regarded as a superclass containing two classes: ray-finned fish and lobe-finned fish. And to complicate matters, lobe-finned fish are sometimes regarded as including the tetrapods. Jawless fish are controversial when it comes to deciding what a vertebrate is. They are sometimes regarded as a superclass, with lampreys belong to the class Hyperoartia and hagfish to the class Myxini. From that viewpoint there are 9 vertebrate classes. I've expanded the IUCN table by splitting fish into five classes. That seems more balanced, since there are as roughly as many fish species as tetrapod species. But there are other ways we could cut the cake. --Epipelagic (talk) 23:57, 10 October 2015 (UTC)

I was working with the "traditional classification" section in the article. I guessed there would be discussion about this, but I was working on the basis that the current lead image appears to suggest there are only 5 classes, conflicting with the text.DrChrissy ^(talk) 11:48, 11 October 2015 (UTC)

Yes, I wasn't arguing against using the 7 animal classes in your image, but arguing for the 9 classes used in the species table. --Epipelagic (talk) 20:50, 11 October 2015 (UTC)

OK - I will work on a montage of those tomorrow. Nine images make for an easier montage arrangement! ;-) DrChrissy ^(talk) 21:15, 11 October 2015 (UTC)

Confusion about the notochord

The article Chordate says

Chordates are animals possessing a notochord

This implies that vertebrates have a notochord. But the present article Vertebrate#Vertebral column (and also the lead of Vertebral column) says that in vertebrates

the notochord ... found in all chordates has been replaced by a segmented series of ... vertebrae

This sounds like it means "has been replaced by evolution with ...", in which case it contradicts the previous quote. But is the latter quote intended to say this instead?:

the notochord ... found in all chordates is present only in the embryonic stage and is replaced later in the organism's development by a segmented series of ... vertebrae

Loraof (talk) 17:38, 7 February 2016 (UTC)

Technically the notochord develops into the intervertebral discs. The sentence should state that all chordates possess a notochord (or structures derived from an ancestral notochord) at some point in their life cycle.--Khajidha (talk) 17:05, 16 February 2016 (UTC)

Birds are reptiles

Birds are reptiles so we should include them as such.

This has been discussed to death on several talk pages, and this is not the place to do it again. You need to be much more careful with the word "are"; birds are certainly part of the reptile clade, but they are a perfectly good class (and clade) of their own, with much distinctive biology and behaviour too. Cladistics is not, in a word, everything. Chiswick Chap (talk) 20:44, 26 July 2018 (UTC)

A Commons file used on this page has been nominated for deletion

The following Wikimedia Commons file used on this page has been nominated for deletion:

• Carcharodon carcharias drawing.jpg

Participate in the deletion discussion at the nomination page. —Community Tech bot (talk) 23:07, 3 March 2019 (UTC)