Talk:Dinosaur/Archive 9

This is an archive of past discussions about Dinosaur. Do not edit the contents of this page. If you wish to start a new discussion or revive an old one, please do so on the current talk page.

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Is there a prejudice against the possibility of aquatic dinosaurs?

I removed the statement that no dinosaurs became aquatic. There seems to be a sort of reluctance to place them in water. This is probably because it is regarded as a retrograde condition (harking back to the image of water-bound, sluggish sauropods). Some dinosaurs may have been amphibious. There is some recent study on the possible amphibious lifestyle of diplodocids. It has been speculated that spinosaurids such as Baronyx may have hunted in rivers. And it seems unlikely that creatures that so successfully dominated every environment (save the seas, dominated by other reptiles, and the skies, dominated by pterosaurs) would not also have taken to the rivers and lakes. Elephants today display no obvious aquatic characteristics. But given the opportunity, they spend much time in water. They may have no specific adaptations to water but they have none mitigating against (observe how versatile the trunk is in varied environments. Likewise the marine iguana has no obvious adaptations to an aquatic lifestyle. That certainly doesn't stop it though! So I suggest we not appear to be dogmatic about the question.--Gazzster (talk) 00:16, 9 June 2008 (UTC)

Could we put our hands on our hearts and say no dinosaurs took to the water? It is harder to believe that none ever enjoyed water than to believe that they didn't.--Gazzster (talk) 00:38, 9 June 2008 (UTC)

Do we have a reliable source (say a peer-reviewed paper) which states any of them were aquatic? Firsfron of Ronchester 00:49, 9 June 2008 (UTC)

Do we have a reliable source to say that none were? There are however studies of diplodocids and spinosaurids that suggest some dinosaurs may have been amphibious. But I am not defending the aquatic habits of dinosaurs: I am pointing out that the statement as it stands is unjustifiably dogmatic and without a citation.--Gazzster (talk) 04:00, 9 June 2008 (UTC)

I think the larger problem is there is no evidence OF aquatic non-avian dinosaurs, and while dipodocids and other sauropods were historically believed to live in swamps, to my knowledge that has been completely discarded. IIRC some spinosaurids were thought to eat fish, but I'm unaware of anyone describing them as aquatic. Titanium Dragon (talk) 10:48, 9 July 2008 (UTC)

No prejudice, we just don't have any yet. If anything, I'd be happy to see "aerial" gone, since there's a decent chance some of the whole mishmash of almost avian nonavians were aerial. "Aquatic" may be a loaded term, though, since the real point is to distinguish them from definite marine animals like plesiosaurs, ichthyosaurs, and mosasaurs. J. Spencer (talk) 04:22, 9 June 2008 (UTC)

OK. Maybe we should use the word marine then. And add that some may have been aerial.--Gazzster (talk) 04:27, 9 June 2008 (UTC)

Or rather, none are known to have been marine creatures.--Gazzster (talk) 04:32, 9 June 2008 (UTC)

First, I agree with J. Spencer's point that we can't say there were no aerial dinosaurs - Origin of birds contains a lot of the details.

"Aquatic" is ambiguous, as it could cover anything from otters or crocs, which are physically not very different from their nearest terrestrial relatives (extinct on the case of crocs), to modern whales, which are practically helpless on land. AFAIK no fossils have been found that are clearly dinos and are at least as well adapted for swimming as they are for walking. Perhaps the article should be equally explicit - and provide a citation or two, as Gazzster suggests. Philcha (talk) 23:32, 9 June 2008 (UTC)

There are several types of aquatic and semi-aquatic dinosaurs. First, there are the birds, of which aquaticness has evolved several times (hesperornids, plotopterids, penguins, etc.), spinosaurs were predominantly coastal and shoreline hunters, eating fish, pterosaurs, and possibly preying on or scavenging small dinosaurs. There is evidence that shows that the primary prey of Ceratosaurus were fish, turtles, and crocodilians, with a lesser emphasis on dinosaurs. But the two reasons why we don't have massive whale-like radiations of dinosaurs is that one, the only major aquatic group (spinosaurs) died out in the Turonian extinction event, and two, the seas were already dominated by mosasaurs, plesiosaurs, icthyosaurs, etc.Metalraptor (talk) 17:05, 14 June 2008 (UTC)

Yes. I thinik it unlikely that most successful animals on the planet at the time did not not radiate into semi-aquatic environments also.--Gazzster (talk) 23:27, 14 June 2008 (UTC)

Well, given penguins exist, and we know they're aquatic... however, it is possible that non-avian never reverted to an aquatic lifestyle. It may be that they were too adapted to living on land, or perhaps they simply didn't have the ability to outcompete crocodiles, amphibians, and the already extant (and now long exinct) aquatic reptiles. I have my doubts that they didn't, but without evidence OF them, we can't say they existed, but I honestly don't think we should include a statement about them being aquatic or non-aquatic at all unless we've got a reliable source. Titanium Dragon (talk) 10:48, 9 July 2008 (UTC)

Fair enough.--Gazzster (talk) 23:16, 9 July 2008 (UTC)

I think there has been a prejudice against the idea of semi-aquatic dinosaurs due to the dicrediting of the once prevalent belief that sauropods needed to live in water in order to support their weight and stop their tails dragging. The rejection of this idea after it was established that dinosaur bones were hollow,has caused a backlash against semi-quaticism. However recent trackway discoveries seem to imply an ornithiscian dinosaur walking on tiptoe- i.e. partially supported by water, soperhaps we should not throw the dinosaur out with the bath water!(lol)--Streona (talk) 11:11, 20 July 2008 (UTC)

Elephants are not hairless

I want to point out that in the Dinosaur page, it contains a piece of information saying elephants are 'hairless.' In reality, they are not. Or you can check out a photo at http://picasaweb.google.com/beckydono/PaiElephantTrek/photo#5052795800087148306. The following website has an elephant's tail with hairs. http://www.globelens.com/african-elephant/ There is also a BBC News mentioning hairs of elephants. http://news.bbc.co.uk/nolpda/ukfs_news/hi/newsid_4567000/4567534.stm?REF=0

If anyone is able to edit the page, please correct the inaccurate information. Thank you. Tc03a (talk) 00:17, 14 June 2008 (UTC)

Size Picture

I think we need to change the size picture on the dinosaurs, for several reasons. One, no marginocephalian is represented, some ceratopsians got very large. Second, while I don't doubt that Lambeosaurus (although Shangtungosaurus could probably give it a run for its money) and Stegosaurus were the largest in their respective category, Amphicoelas and Spinosaurus were doubtful. Amphicoelas and the big B (I forget the name of that Indian sauropod) are known from dubious remains. Amphicoelas was named by a guy who was trying to one-up his rival, and the bone has been subsequently lost. It is very possible that he lied about its size to get one over on Marsh. As for the big B, part of its skeleton (which consists of only two bones) turned out to be a theropod. Until we get a good skeleton of it, it really can't be the biggest dinosaur. As for spinosaurus, I consider its large size dubious. Its current sixty foot size is inferred from a maxilla from Africa. Until we come up with a complete skeleton (or at least one that consists of more than fragments), it is doubtful that Spinosaurus is the biggest. I'm not doubting there could be a sixty foot long spinosaur, or a real Amphicoelas, but until we find more concrete evidence supporting them, we should add sillouhettes of the current record holders (Argentinosaurus and either Giganotosaurus or Mapusaurus).Metalraptor (talk) 17:11, 14 June 2008 (UTC)

These size comparisons are always contentious. The text does explain that Amphicoelias may have been the largest (my own belief is that it was a genuine find and Cope did not exaggerate the size of its vertebra). The artist may very well have substituted Diplodocus hallorum or Argentinosaurus in its place however. But the purpose of these comparative diagrams is not to show the biggest, or nastiest, but to give an idea of the massive sizes dinosaurs could reach. Today we find certain individual animals of a species which far exceed the average dimensions of that species. No doubt the same happened with the dinosaurs. A 120 ft Diplodocus may simply be an overgrown individual. So I suggest we treat all such comparative diagrams as suggestions, not dogmatic statements. And in the context of the text, this is what is intimated here.--Gazzster (talk) 23:13, 14 June 2008 (UTC)

Tail dragging

Correct me if I'm wrong but I think before the 1990s, it was widely believed that dinos dragged their tails. Now, we know that they use them as a counterbalance. Should this be in the article? I don't think it's there. 207.179.153.124 ([[User talk:207.179.153.124|talk]]) 14:41, 17 June 2008 (UTC)

It was noticed far before the 1990s by several scientists, but it was not generally accepted before the 70s. By the begining of the 80s it was perfectly assumed. Just compare, in youtube, the "dinosaur segment" of The animal world (directed in 1956 by Irwin Allen) with the 1985 television documentary Dinosaur!, hosted by Christopher Reeve. You'll see ;-) 343KKT Kintaro (talk) 22:12, 20 August 2008 (UTC)

Not all of the dinosaurs held their tails in the air as counterbalance. Dinosaurs such as brachiosaurus probably kept their tails pretty close to the ground, though they were probably held slightly up. It was only the dinosaurs that were often attacked or that attacked others that needed the counterbalance the most.

It would be presumptuous to suppose that dinosaurs never rested their tails on the ground.Most animals with long tails do.--Gazzster (talk) 10:03, 9 July 2008 (UTC)

Several dinosaurs simply could not have rested their tails on the ground: they would have had to have had their tails broken to accomplish this. Firsfron of Ronchester 12:49, 9 July 2008 (UTC)

The current view is that all dinos, even the huge sauropods, evolved from small, bipedal forms. For a long time bipedal dinos were reconstructed in a "kangaroo-like" posture, with their backs sloping and their tails dragging. In this posture the femurs (thigh-bones) would have been angled backwards relative to the spine, especially in the trailing leg while walking (see picture). Then it was realised that at this angle their hip joints would be near or even past the point of dislocation. So biped dinos are now restored with their spines approx horizontal. That would require a dragging tail to be bent down much more sharply than appears to be possible in most cases, and in addition having the body horizontal meant that a stiff horizontal tail was required as a counter-balance.

Even in quadrupedal dinos such as sauropods the proximal parts of the tails (closest to the body) have features that would have made that part of the tail fairly rigid — spines on the vertebrae that overlap neighboring vertebrae and / or attachments for stiff tendons that bound the vertebrae.

On the other hand ideas that Diplodocus could have defended itself by using its tail as a whip imply that a lot of the rear part of Diplodocus’ tail was pretty flexible. Exceptions like this indicate that there was too much variation for Dinosaur to accommodate, and the best place for this sort of analysis is in the articles about major clades such as Theropoda, Sauropoda, Ankylosauria, etc. -- Philcha (talk) 13:46, 9 July 2008 (UTC)

dinosaur

personally i find this section in etymology to be a little awkward and pointless (i am also unaware of the word meaning unsuccessful): "In colloquial English "dinosaur" is sometimes used to describe an obsolete or unsuccessful thing or person, despite the dinosaurs' 160 million year reign and the global abundance and diversity of their descendants, the birds. This usage became common while dinosaurs were regarded as cold-blooded and sluggish."

also, i wonder if the introduction and the first section on etymology should just be merged. they seem very similar. —Preceding unsigned comment added by Fantiquitous (talk • contribs) 01:22, 5 July 2008 (UTC)

Oxygen

If the dinosaurs had respiratory systems similar to those commonly found in modern birds, it may have been particularly difficult for them to cope with reduced respiratory efficiency, given the enormous oxygen demands of their very large bodies Unfortunately, I cannot access the reference, but the sentence looks like bullshit; birds are far more tolerant to low oxygen levels than mammals and dinosaurs were okay in oxygen-deficient Triassic and Early Jurassic times.Alliumnsk (talk) 16:10, 13 April 2009 (UTC)

It also fails to account for the fact that most dinosaurs did not have very large bodies. Dinoguy2 (talk) 16:21, 13 April 2009 (UTC)

Thermoregulation

I should like to object to the vulgar view that "cold-blooded" means sluggish in dinosaur terms. The Mesozoic era was a time when the ambient temperature was much higher than now and the oxygen content of air greater. Ectothermy may have resulted in higher body temperatures than endotherms, who may have had to regulate their temperature downwards. Heat regulation among warm blooded or endothermic animals is usually held to imply the production of inner body heat by food consumption, whereas there are other forms of heat production - such as that in bumble bees, who have a high body temperature induced by the exercise of their wings. Endothermy seems a very inefficient mechanism in the context of the Mesozoic environment, devoting 80% of food consumption to thermo-regulation instead of growth which may account for mammals relative lack of success in this period. Insulating media such as feathers and down may equally have served to preserve nocturnal core temperature in ectotherms as to imply endothermy--Streona (talk) 22:43, 17 July 2008 (UTC)

The terms "cold-blooded" and "sluggish" appear in a sentence that describes common perceptions before Ostrom and Bakker got to work. You're right to point out that ambient temperatures were higher than now and the oxygen content of air greater in the Mesozoic. But there's a set of reasons why sustained activity seems to require a fairly high and stable body temperature for vertebrates - see Physiology_of_dinosaurs#Metabolism for a more detailed explanation. Even in warm climates such as Florida or the tropics, ectothermic terrestrial vertebrates lack stamina - they can move as fast as endotherms for a few seconds, but then need a long rest. Insects are different because their small sizes give them superior power-to-weight ratios (muscle power is proportional to area, mass is proportional to volume) - but even so, bees do "warm-up" exercises before flying, especially early in the morning. And aquatic creatures are different because they are not constantly fighting gravity when they move. -- Philcha (talk) 23:08, 17 July 2008 (UTC)

But I think sometimes in editing dinosaur articles some of us tend to forget that the arguments for endothermy amount to nothing more than strong suggestions, not proof.And there is a case for ectothermy as well, as explained (but not necessarily supported) by Reese Barrick (Book of Dinosaurs, Scientific American, p.314, 2000) He also explains the case for a third possibility, mesometabolism. And then, of course, there is the possibility that metabolism varied between species, just as metabolism varies greatly amongst mammal species today. As Streona intimates, 'cold-blooded' is misleading, because ectothermy does not mean inefficiency or inactivity. And even a 'cold-blooded' giant dinosaur could sustain moderate to high levels of activity (though factors such as size and bone mass would mitigate against high levels). In moving away from the notion that dinosaurs were 'sluggish', we have conversely reinforced the idea that 'cold-bloodedness' is a deficient means of thermoregulation. That's not fair on our reptilian friends, who are very clever and efficient chaps.--Gazzster (talk) 00:20, 18 July 2008 (UTC)

Id like to object to the statement of birds and crocidilians being the only living ancestors of dinosaurs, as a New Zelander I am somewhat offended that the closest living relative the Tuatara lizard was completly overlooked —Preceding unsigned comment added by Wmagic1990 (talk • contribs) 21:47, 21 November 2008 (UTC)

No, the Tuatara is more closely related to lizards and snakes than to crocs, dinos and birds - see Tuatara#Taxonomy_and_evolution. --Philcha (talk) 22:27, 21 November 2008 (UTC)

weights are a problem

In the size section there are some, well, rather incorrect metric to US conversions:

…most often fall into the 100 to 1,000 kilogram (500 to 4,500 lb) category, whereas recent predatory carnivorans peak in the 10 to 100 kilogram (50 to 450 lb) category…

I don't know which is right, but 100 to 1,000 kg does *not* correspond to 500 to 4,500 lb (nor does 10 to 100 correspond to 40 to 450). So which is the basal number here? I presume the metric amounts, so I am going to change the lb weights to 220 to 2,200 and 22 to 220 respectively. If the pound weights are the basis here, someone will need to fix the change and correct the metric weights, but the present conversions are off by well over a factor of 2 in one direction or the other.

-Fenevad (talk) 11:35, 19 July 2008 (UTC)

Diplodocus did not have a semi-aquatic lifesyle!

I would like to point out that on one part of this talk page suggests that diplodocus had a semi-aquatic lifestyle.there would be lots of pressure on the diplodocuses lungs if it wnt in the water and would probably squashed its lungs and killed it! 5:49 pm, 19 July 2008 ([[User:Streona (talk) 17:01, 19 July 2008 (UTC)[[)

I'm not defending the idea of a semi-aquatic diplodocus, but this old objection is not as sound as it may appear. Many modern creatures have adaptations to cope with water pressure and there is no reason to suppose some dinosaurs could not have evolved similar adaptations. But there is no reason why a diplodocus would have had to submerge its whole body anyway. It may have wallowed like an elephant. There are objections to browsing sauropods on the grounds of pressure to the heart. But it is similarly counter-argued that animals such as giraffes have evolved mechanisms to overcome stress on the heart and so we might reasonably expect such in the sauropods. We talking about extinct creatures whose soft tissues have not, for the most part, been preserved.--Gazzster (talk) 20:52, 19 July 2008 (UTC)

It is perfectly sound; diving 10 m with holding breath is very different from breathing submerged at same distance. In the first case, lungs contract until air pressure in lungs equals water pressure at chest plus athmospheric pressure, so there is a limit of how lungs may contract to. In the second case, lungs contract too, but pressure in lungs will be still equal to athmospheric, so animal's ribs and muscles have to sustain strong pressure, and if they not - chest cavity will be entirely crushed. There is a reason to suppose that no sauropods could have evolved similar adaptations as cetaceans, because sauropods plainly lack any adaptaions associated with aquatic lifestyle.16:01, 13 April 2009 (UTC) —Preceding unsigned comment added by Alliumnsk (talk • contribs)

It was recently suggested that a sauropod could not be submerged anyway, due to internal air spaces (BBC): you couldn't have a sauropod walking on the bottom of a lake with its nose sticking up because the rest of it would be floating as well! J. Spencer (talk) 00:31, 14 April 2009 (UTC)

Dinos did not diversify much in the Cretaceous

I just got notice of a new paper, Dinosaurs and the Cretaceous Terrestrial Revolution (KTR), by Graeme T. Lloyd and a cast of thousands, which argues that:

Raw statistical data (e.g. Fastovky) shows a late-K diversification of dinos, but it's an artifact caused by sampling bias.
Dinos did not take advantage of the new opportunities offered by the rise of angiosperms, while insects, lizards, snakes, crocs, mammals (notably placentals) and birds did. Dinos had only 2 significant diversifications in the Late Cretaceous, the initial radiations of the euhadrosaurs

and the ceratopsids.

The KTR was a key in the origination of modern continental ecosystems, but the dinosaurs were not a part of it, and this may have doomed them.

Sounds like a revival of the old "senescence" idea, or a more sophisticated version of the old "alkaloid poisoning" idea. -- Philcha (talk) 17:37, 28 July 2008 (UTC)

I think it's too early in the game to draw too many conclusions, but it's interesting to think about. J. Spencer (talk) 23:59, 28 July 2008 (UTC)

I wouldn't take notice of anything Graeme says! Lol. No it's really good work, shame Nature and Science pasted it over, but at least its finally out now! Mark t young (talk) 00:02, 29 July 2008 (UTC)

"Nature and Science pasted it over". You mean they tried to paper over the cracks, or they missed a good opportunity to polish an interesting pepper? — Philcha (talk) 07:40, 29 July 2008 (UTC

:p passed. I always make stupid spelling mistakes like that with keyboards. Mark t young (talk) 18:30, 4 August 2008 (UTC)

Birds

This article does not metion much about dinosaur/bird relationship or the fact of including birds as a dinosaur ingeneral. Yes it does metioned birds evolved from theropod dinosaurs. And does lable birds as the only living dinosaurs. The whole thing though is that when dicussing dinosaurs in the article it metioned the origins of birds but not dicussing birds as dinosaurs or giving birds their own section in the article. I think birds should have a short article in the dinosaur page that gives a short summary of how modern day dinosaurs (birds) live and behave, with a link to the Bird article. All that is metioned on how dinosaurs are separate from birds should be eradicated and the article should be more of a possitive focus on birds being dinosaurs. Meaning that metioning dinosaur extinction is obsolite (you can metioned the K-T extinction event and the speices that died out but can not metioned that dinosaurs ingeneral are extinct). So the fossil record should change from Trassic-Cretaeous to Trassic-Resent. The Dinosaur article needs to be more bird friendly. —Preceding unsigned comment added by Westvoja (talk • contribs) 08:12, 14 August 2008 (UTC)

Dinosaur has a section Feathers and the origin of birds, which summarizes and links to the "main article" Origin of birds. "Feathers and the origin of birds" is a little brief and the content is not as how I would have written it, but these are matters of individual taste. Dinosaur is a pretty long article, and that limits the amount of detail that can be given about birds. Instead it concentrates on explaining dinos, including the group of dinos from which birds are thought to have evolved, and I think that plus the link to Origin of birds is a pretty helpful way to package the vast amount of information that has to be summarised. If you'd like to read these 2 articles, plus Cretaceous-Tertiary extinction which you also mentioned, and then suggest at this Talk page how much detail the summary versions should contain, I'm sure your suggestions would be taken seriously, and any with with editors disagree will be answered helpfully and courteously - most Wikipedia articles need feed-back from non-specialists. -- Philcha (talk) 10:35, 14 August 2008 (UTC)

Sorry Philcha, but I agree with Westvoja. In addition this paragraph should be entirely replaced : "It is also technically correct to refer to dinosaurs as a distinct group under the older Linnaean classification system, which accepts paraphyletic taxa that exclude some descendants of a single common ancestor". Why should it be entirely replaced ? BECAUSE IT'S FALSE. The Linnaean system does not accept or refuse paraphyletic or monophyletic taxa... those terms ("paraphyletic taxa", "monophyletic taxa"...) have no sens in old Linnaean classifications because in Linnaean the question itself about such concepts is not even formulated. "Technically correct" means nothing... or it even means "false". It is indeed very confusing for the reader, who should learn what's correct (phylogenetics is correct) and what's wrong (Linnaean is wrong, or being more accurate : Linnaean doesn't have an objective criterion of classification). I suggest the following lines:
"In modern popular terms the word dinosaurs still refers to a traditionnal conception of extinct giant reptiles who excluded birds from their membership. This conception is only a popular persistence of an old abandoned status of classification, the Linnaean one. Modern scientific classification methods (cladistics and phylogenetics) include birds in dinosaurs and that's why birds are dinosaurs. The popular persistence of the idea that birds are not dinosaurs is anyway inevitable in popular culture (comics, movies, fantasy novels) or in popular opinion, but is no longer accepted in systematics."
This text, or a similar expression, is what we should offer, in my opinion, to the reader. 343KKT Kintaro (talk) 21:57, 20 August 2008 (UTC)

I sympathise, since I'm currently working mainly on articles connected the Cambrian explosion. Many of the critters involved are very hard to fit into a Linnean-style classification, so cladistics and the concepts of stem and crown groups are generally more useful there. But the "taxonomy" sections of scientific articles that discuss the Early Cambrian critters in cladistic terms nevertheless generally use the Linnean species-genus-family-order-class-phylum hierarchy in their "taxoboxes". The sentence "It is also technically correct to refer to dinosaurs as a distinct group under the older Linnaean classification system, which accepts paraphyletic taxa that exclude some descendants of a single common ancestor" accurately summarises current practice, irrationally conservative though it may be. -- Philcha (talk) 22:18, 20 August 2008 (UTC)

The cambrian explosion? that's a fascinating subject, nice from you to keep the line on such interesting articles (I know I couldn't write a single word on this particular and difficult subject). But anyway in terms of systematics (in all the Wikipedias) I think we really should abandon the so called "taxoboxes", or change them by replacing the ranks hierarchy by a cladogram. When you say "current practice" you are wrong, it is the (wrong) current practice in Wikipedia to use taxoboxes with ranks in every article concerning taxons or species, but IS NOT current at all tu use them in modern systematics. Searchers don't use them and serious modern books neither. The current status of science is that cientists only investigate possible cladograms and don't take care any more about ranks. Only a few authors try to continue establishing a system of ranks, by putting (boldly!) modern monophyletical taxa into them, but such classifications are a sort of hybrid, an artificial "artifact", and don't correspond to the majority of "systematicians" (should we say "systematicists" ?). I already said in the Wikipedias where I can read and write (french, english, catalan and spanish) that we should abandon taxoboxes and use only phylogenetical cladograms (the old Linnaean taxoboxes with their ranks being shown to the reader in specialised articles where it could be clearly explained that they are abandoned). I need to be followed on that motion, followed by a majority of wikipedian authors, but for the moment it's not the case... why? your "technically correct" is still in fact a "totally wrong" sentence! Friendly : 343KKT Kintaro (talk) 00:02, 21 August 2008 (UTC)

I meant current practice in scientific journals - which Wikipedia then follows. I guess part of the problem is that the Linnean system still works quite well for modern animals, and then for fossils that are obviously closely-related to modern animals - e.g. mammoths and mastodons; or, going further back, dinosaurs and birds. The Mid Cambrian is the latest point at which there are fossils that clearly do not fit the Linnean system, but OTOH no-one seriously doubts that the very Early Cambrian helcionellids were molluscs. So there's no simple criterion for deciding at what geological time to stop using the Linnean system.

There's a further problem. It's simple enough to describe e.g. Marella as an arthropod (phylum) of an unknown class (it's almost certainly not a trilobite, chelicerate, crustacean, hexapod or myriapod), and this does not commit the author to a specific theory about its ancestry as a cladogram would.

However I think that's enough, as this Talk page is supposed to be about dinosaurs! -- Philcha (talk) 00:24, 21 August 2008 (UTC)

If you want to talk about getting rid of the taxoboxes, or replacing them with cladoboxes, you should bring it up at Wikiproject TOL. But I don't know how far you'll get, that has been tried without success many times by now. Dinoguy2 (talk) 05:46, 21 August 2008 (UTC)

Christianity

Tangential religious discussion

The following discussion has been closed. Please do not modify it.

At school, they taught us dinosaurs were extinct long before there were people. Does that mean our school went against the truth, that God made animals and people in the beginning, at the same time? —Preceding unsigned comment added by 72.192.94.145 (talk) 03:31, 15 August 2008 (UTC)

Truth is specific to an individual's beliefs. What might be true for you might not be true for me, and vice versa. Maybe your school did not teach something that is true for you, but it doesn't make it any less valid. -- Diggsey (talk) 18:38, 12 October 2009 (UTC)

No. Your school is right. Genesis says that God made different aspects of the world on different days. A "day" may be a metaphor for a much longer period. At the time it was written people had little idea of very large numbers or periods and the Earth shows innumerable evidence of being much more ancient than medieval biblical scholars estimated. If this is not so then the creator of the world would be planting false evidence and why would that be? Some 19th century Christian apologists tried to say that the Devil planted this evidence. However the geological evidence is so widespread, this would be tantamount to saying the devil had made the whole Earth- a view held by some medieval gnostics who were generally burnt as heretics. Given the extreme age of the Earth and the millions of generations involved, evolution is inevitable. This was first proposed by Muslim scholars in the 9th century.--Streona (talk) 05:48, 15 August 2008 (UTC)

I don't think so. In Genisis it said "And the evening and the morning were the sixth day" that sounds like a day to me; a twenty-four hour period. --Special:Contributions/Fwooper (talk) 23:27, 26 August 2008 (UTC)

Here's something to think about then: the sun was created on the fourth day. A day is the measure of the rotation of the earth in relation to the sun. So how can the days of creation be literal 24 hour periods before the fourth 'day'? And if we're going to use the Bible in a scientific discussion, 'to the Lord a day is a thousand years, and a thousand years a day'.And, raising a philosophical point, why should a Deity which exists outside time be limited in its actions by events in time?--Gazzster (talk) 00:20, 28 August 2008 (UTC)

God created light and dark the first day. The light wasn't necessarily the sun. —Preceding unsigned comment added by 70.184.39.134 (talk) 13:55, 17 September 2008 (UTC)

You mean the Big Bang? -- Philcha (talk) 14:03, 17 September 2008 (UTC)

Sweet mother of God, what part of allegorical is difficult to grasp? The Jews don't even take the book of Genesis literally, and they wrote the book. The entire book is an allegory meant to teach valuable lessons as well as construct a framework which served as an ideological foundation for a particular religion, Judaism. No where in the book does it suggest that every passage should be taken literally and in fact its form would lead one to believe the opposite. If one knows anything about ancient Hebrew culture or Judaism in general, he or she should know that the type of allegorical framework being used in Genesis is common. No one actually believes that there really was a prodigal son or that the three men with the talents or that the kingdom of God is 'literally' a bunch of scattered seeds, and the list goes on and on. Did Jesus ever outright say that these stories were figurative or didn't literally happen? No, it was a given. Why did he talk like this? Because it was a style of narrative teaching that was immediately familiar to his Jewish audience. Does the book of Genesis ever come outright and say that it is an allegory? No, it's a given. Stop trying to judge scientific issues through a bizarre and erroneous interpretation of Genesis. You can have faith in God or Jesus all you want, but when you put absolute faith into human interpretation (and translation, for that matter) you will always end up looking foolish. —Preceding unsigned comment added by Jdlund (talk • contribs) 01:06, 1 October 2008 (UTC)

bald statement that birds are dinosaurs?

I understand that in cladistics, birds must be considered dinosaurs. And the article correctly (at least in broad outline) describes the different senses of the word "dinosaur" later in the article. But the last sentence of the intro is, "Today there are 10,000 living species of dinosaurs that are commonly known as birds." I think this needs some qualification; cladistic definitions are not yet universally adopted, as one can see in various dictionaries. How about, "By cladistic definitions, today there are 10,000 living species..."? For comparison, our article on bacteria begins, "The Bacteria are a group of unicellular microorganisms." If cladistics were universally adopted, this sentence would be something like, "The Bacteria include all life on earth, except viruses." --Allen (talk) 20:17, 22 August 2008 (UTC)

I'd prefer "Today there are 10,000 living species of dinosaurs, the ones we know as birds." But it's no big deal any way - there are enough TV pop science programmes that say birds are dinos. Besides, the tone of WP articles is often downright sombre or even soporific, and a statement that wakes readers up is a Good Thing.

I don't think Bacteria is a good example, as AFAIK bacteria do their best to undermine the species concept by frequent horizontal gene transfer. Since it's generally accepted that eukaryotes were produced by a series of these, most importantly by endosymbiosis of an aerobic eubacterium with an anaerobic archaean, it seems the first true eukaryote had immediate ancestors that may have belonged to more than one domain. Hence the eukarote family tree resembles a braid rather than the hierarchy that cladistics assumes.

Witty comments on "horizontal gene transfer" are welcome :-) -- Philcha (talk) 20:52, 22 August 2008 (UTC)

True what you say about eukaryote evolution. Fish are another example I like to use when trying to point out how incomplete our adoption of cladistic definitions is. --Allen (talk) 21:18, 22 August 2008 (UTC)

I'm a Pisces, so I have to agree -- Philcha (talk) 22:20, 22 August 2008 (UTC)

You're a pisces? Talk about horizontal gene transfer! (Oh crap, you said witty...) --Allen (talk) 01:48, 23 August 2008 (UTC)

'What's in a name?' the saying goes. Names are simply labels. The label, in this case, 'dinosaur', is usually attached to a reptile of the Ornithischia or Saurischia. It is not usually attached the creatures we group in the Aves. That is one consideration. Let us remember also that there are a scientists, albeit in the minority, who dispute that your budgerigar is a dinosaur. Some say that the resemblances between birds and dinosaurs may represent a case of convergent evolution.They may be right. They may be wrong. The truth is that the truth is not known for a fact. The truth may never been known. Or the 'truth' once established, may be in time debunked or replaced by a more trendy theory.--Gazzster (talk) 12:47, 27 August 2008 (UTC)

Presumably birds are bird-hipped, but descended from lizard-hipped dinosaurs. This has always struck me as odd. Also that if birds diverged from dinosaurs in the Jurassic (Archaeopteryx) they did not therefore descend from Cretaceous raptors.--Streona (talk) 14:18, 27 August 2008 (UTC)

Yes, the hip-thing is a problem.--Gazzster (talk) 00:23, 28 August 2008 (UTC)

The hip thing is an adaptation to herbivory/omnivory, and doesn't have much to do with classification. It evolved several different times among dinosaurs. It shouldn't be "bird-hipped" as much as "herbivore-hipped." The arrangement allows for a longer digestive system. The ancestors of birds (and dromaeosaurs?) appear to have been at least partly herbivorous (troodonts, oviraptorosaurs, and therizinosaurs are all at least omnivores. Since only dromies are the odd man out, they may have re-evolved pure carnivory).

And no, of course they didn't descend from Cretaceous raptors. They descended from Jurassic raptors, which everybody seems to forget about... there are "raptors" from the same time as and before Archaeopteryx. Troodonts lived in the late Jurassic (Koparion, "Lori", possibly Jinfengopteryx). Scansoriopterygids and Pedopenna (ancestral to raptors) lived before Archaeopteryx. Teeth that appear to come from true dromaeosaurs are found in the Middle Jurassic. Palaeopteryx from the Morrison formation may be a dromaeosaurid. Dinoguy2 (talk) 01:28, 28 August 2008 (UTC)

And there's the enigmatic Protoavis to fall back on, even though Chatterjee and everyone else seems to have distanced himself from making it a bird. Doesn't look much like a bird to me. We may never know the answer. Dromaeosaurs? Archosaurimorphs? I like mystery. It may be the ancestor is still nicely snugged up in its chunk of rock, waiting to be discovered. And it may be something utterly unexpected. I mean, who would have thought Scutosaurus was related to a turtle, as is speculated? --Gazzster (talk) 07:00, 3 September 2008 (UTC)

Odd bird statement

"Today there are 10,000 living species of dinosaurs that are commonly known as birds." - This seems a bit dubious... birds aren't dinosaurs any more than humans are small shrewlike creatures from which mammals evolved. 81.157.243.185 (talk) 10:24, 26 August 2008 (UTC)

There are a few ways of classifying organisms. The oldest one still in use, devised by Linnaeus, regards dinos as reptiles and birds as something else, namely birds. But Linnaeus' system was produced before scientists knew about evolution, and does not handle extinct organisms very well. The classification system most used in studies of evolution and of extinct creatures is cladistics, which tries to draw up a "family tree" of organisms. Under this scheme, birds are dinosaurs since they evolved from one group of dinos; and if you trace back through the family tree you'll see that birds and dinos are archosaurs, diapsids, amniotes, tetrapods, fish(!!), chordates, deuterostomes, bilaterians, metazoa and eucaryotes. Likewise humans are primates, mammals, therapsids, synapsids, amniotes (this group contains the last common ancestor of all mammals and all dinos), tetrapods, fish(!!), chordates, deuterostomes, bilaterians, metazoa and eucaryotes. -- Philcha (talk) 10:56, 26 August 2008 (UTC)

I do agree, though, there is one very dubious notion, namely Using the strict cladistical definition that all descendants of a single common ancestor must be included in a group for that group to be natural, birds are dinosaurs and dinosaurs are, therefore, not extinct. - this would make all land-living vertebrates fish! Grouping birds into the dinosaur taxon is either a misintepretation of that statement (as it would prevent introduction of ANY new taxon during the course of evolution) or inconsequential 90.134.120.187 (talk) 12:39, 10 October 2008 (UTC) (btw. that identification won't help you recognize me as my IP changes every 24 hours. But I'm too lazy to create an account)

I just said that birds are dinos, archosaurs, ..., and eucaryotes; and we are fish, and chordates, ..., and eucaryotes. This does not prevent the introduction of new taxa, for example if ET biologists tracked the course of evolution on this planet they'd have seen the appearance of and defined new taxa for fish, tetrapods, amniotes, ..., and humans - but the new taxa would be contained within the existing oes, like Russian dolls. Right now I don't know how many new insect species are discovered per year, and new taxa are defined for them (more Russian dolls). Grouping birds into the dinosaur taxon is not inconsequential, as it implies that dinos are not extinct, and that at one time there must have been a few birds that were very like non-bird theropods and a few non-bird theropods that were very like birds. This has a lot of implications, e.g.: dinos are not one monolithic lump but varied a lot, both over time and at any one time between about 190 million years ago and 65 million years ago, and the survivors (birds) have diversified very successfully since then; since birds are warm-blooded, there's a big debate about whether any non-bird dinos were warm-blooded. -- Philcha (talk) 13:10, 10 October 2008 (UTC)

"Birds are dinosaurs"??? You must be bloody kidding me. I won't get drawn into an argument over claudistics or the strict scientific justification, or how it is like saying "Man" is an "Ape" (although sometimes I wonder.) Let me just say it's statements like this that make WP look silly and unprofessional to the average reader. JQ (talk) 02:37, 6 March 2009 (UTC)

Thanks for your suggestions. We'll refrain from including the opinions of professionals next time. Dinoguy2 (talk) 03:26, 6 March 2009 (UTC)

You have it backwards, JQ. Saying birds are dinosaurs is as professional as it gets. Go ahead, ask a professional. The only people (well, almost) who wouldn't say that birds are dinosaurs are laymen (non-professionals). So actually, saying that birds AREN'T dinosaurs would be the unprofessional way to go. Sheep81 (talk) 05:52, 6 March 2009 (UTC)

I wouldn't dispute there's fact to the statement, but just perusing the article the sentence is poorly worded and sticks out like a sore thumb. WHO has classified birds as dinosaurs? Briefly, why? Is it really a case of 'have officially been' or 'may be'? (It makes it sound, for instance, like anyone would be perfectly entitled to point at a blackbird and say "Look! A dinosaur!) Is it really so uncontroversial as to be unreferenced?--Tomsega (talk) 21:05, 11 June 2009 (UTC)

Actually, it is referenced. From the same section: "Research has since identified theropod dinosaurs as the most likely direct ancestors of birds; most paleontologists today regard birds as the only surviving dinosaurs, and some suggest that dinosaurs and birds should be grouped into one biological class.[1]" That's sourced to Bakker and Galton (1974). Wikipedia:LEAD#Citations indicate that since the lede is supposed to cover the material in the rest of the article, that citations in the lede are undesirable anyway. The guide recommends placing them in the body of the article, so another citation in the lede, when there's already one in place, probably isn't necessary. Firsfron of Ronchester 01:48, 12 June 2009 (UTC)

Interesting. I went to the Page museum 2 days ago and asked this very question to 3 paleontologists and they disagree completely. When specifically talking cladistics to other paleontologists yes, they use the term birds are dinosaurs. But when talking to other scientists, laymen, people in general and writing books, they never use the term at all. They said it was simply the weird terminology that cladistics demands that makes then use the term birds are dinosaurs at all. Any other time it is simply said birds descended from dinosaurs. I should also say the a 4th paleontologist there, who came into the end of the conversation, would not admit at all that birds descended from dinosaurs. Keeping it this way in the article is confusing to the general populous and wrong except in the tiny confines of cladistics. Dump it. Fyunck(click) (talk) 02:39, 12 June 2009 (UTC)

The Page Museum isn't a dinosaur museum, is it? We're not dumping material referenced to a peer-reviewed paper on the subject in favor of a personal anecdote at a museum which doesn't display or study dinosaurs, just as we couldn't say, take a verbal statement from an expert at a Civil War museum regarding the Revolutionary War. Firsfron of Ronchester 05:07, 12 June 2009 (UTC)

No it is not, but that wasn't the point of contention as you deftly try to twist the subject. It has paleontologists and that's what we were talking about. They use many of the same terms for prehistoric life as you do for dinosaurs. This article is about dinosaurs not cladistics. Cladistics certainly should be mentioned here and then linked to the proper page but it should not be used exclusively because you say it should. It bothered me here for awhile but I let it go as I do most things when there are people writing on a subject more knowledgeable than I. I now know after a simple museum visit (that anyone can do) that the term "birds are dinosaurs" is NOT generally used. In the coming weeks I have a natural history museum and a university visit scheduled so I will see if the paleontologists there agree or disagree with the wording in an an all-encompassing dinosaur article. I only asked at one place but the results were 100% against you so I would say this is far from cut and dry as to using cladistics in the first paragraph saying birds are dinosaurs. Again I'm not saying it shouldn't be mentioned here... it should, but only briefly, with the main thrust saying that birds evolved (or likely evolved) from dinosaurs not that they are dinosaurs. Fyunck(click) (talk) 05:43, 12 June 2009 (UTC)

This discussion needs some common sense. In ordinary speech (based on very dim folk-memories of Linnaeus) birds are not dinos, but in the opionion of the vast majority of paleontologists (an even greater majority of whom use cladistics as their primary classification tool) birds are dinos. It's really easy to find good sources for the majority paleo view. It's probably harder to find good sources for the ordinary speech use of "dinosaur", because the most likely sources are dictionaries. It's to readers' advantage to point out the the majority paleo view, because they'll find it in library books about dinos. Doing that means acknowledging the existence of the ordinary speech use of "dinosaur". --Philcha (talk) 06:03, 12 June 2009 (UTC)

PS Merriam-Webster --Philcha (talk) 06:07, 12 June 2009 (UTC)

<CR> One doesn't surround an article on humans saying "humans are fish." You might touch on it saying something midway through the article like "using a strict definition of cladistics, humans are fish... to understand more see the article 'cladistics.'" Then move on to the traditional humans evolved from fish. That's all I'm saying should happen here imho. Fyunck(click) (talk) 06:53, 12 June 2009 (UTC)

The gap between "dinosaurs"_ordinary and birds is negligible, and in shape birds are clearly theropodss. And enough dino programmes on TV have pointed this out. OTOH boths humans and dinos are cladistically fish, but are several steps removed from fish in the relevant lineage, and have very un-fishy shapes and lifestyles. --Philcha (talk) 07:05, 12 June 2009 (UTC)

The "humans are fish" analogy is a (heh) red herring. As our fish article states, fish are not a single clade but a paraphyletic grouping. Thus it won't even be cladisticly sound to say that humans are fish. Note that the fish article, though, does get into cladistic discussion. Firsfron of Ronchester 07:57, 12 June 2009 (UTC)

Firsfron of Ronchester, I think you need to re-read paraphyly. That article's explanation shows a cladogram topology that applies equally well (i.e. very) to "humans are fish" and to "birds are dinos". Paraphyly is the reason for the ambiguity of the term "dinosaur". --Philcha (talk)

I do not misunderstand, nor do I need to re-read paraphyly. Please, Philcha, refrain from the "you need to re-read" stuff. Fish aren't a clade (as you can read in the fish article: "Fish are a paraphyletic group: that is, any clade containing all fish also contains the tetrapods, which are not fish. For this reason, groups such as the "Class Pisces" seen in older reference works are no longer used in formal classifications.") Humans can be classified as chordates, but not as fish. All birds can be classified as Aves, a group that comes under dinosaurs in published cladograms. Firsfron of Ronchester 09:24, 12 June 2009 (UTC)

Your statement "The "humans are fish" analogy is a (heh) red herring" is ... a red herring. If you don't like my response to your derogatory comment, you should not have made it.

"The "humans are fish" analogy was relevant. If dinos are a clade, then so are fish, provided "fish" includes tetrapods, which is quite reasonable when you look at the origins of tetrapods. However you find plenty of TV programmes and popular science articles calling birds dinos, but I can't remember seeing any call humans fish - presumably because they don't want to bother tracing the rather longer evolutionary arc from the piscine LCA to humans. As Dinoguy2 points out below, top dino paleontologists like Holtz publicly explain why birds are dinos. All we need is for one of the holy trinity of early tetrapods to say it in a popular article - Jennifer Clack comes close in Getting a Leg Up on Land. --Philcha (talk) 19:56, 13 June 2009 (UTC)

I don't appreciate your comments to me only because they're rude in tone. "You need to re-read" stuff is rude (especially when it's wrong). Please, Philcha, just stop with the passive-aggressive commentary toward me. It's really old by now. I'm asking this as a favor; I don't critisize you, and I'd expect the same from you. Fish aren't a clade, so the comparison is a red herring: it's not the same thing. Firsfron of Ronchester 20:44, 13 June 2009 (UTC)

Your "The "humans are fish" analogy is a (heh) red herring" was a disparaging remark, and I didn't find it as amusing as you evidently did.

If you want to maintain that the "humans are fish" analogy is irrelevant, please explain why the topology of a cladogram showing all fish but excluding humans differs significantly from that of one showing all dinos but excluding birds. --Philcha (talk)

Philcha, I've asked you repeatedly to stop. If you continue to respond to me again, I plan to open a request for comment. Again, please stop. Firsfron of Ronchester 22:04, 13 June 2009 (UTC)

Fyunck: if the scientists at the page museum haven't published those opinions, they don't exist as far as Wikipedia is concerned. Period, end of discussion. On a side note, just because they believe the public should have science simplified for them to the point you need to say one thing to experts and the opposite to laymen doesn't mean they're right. One of the most well-respected and prominent dinosaur paleontologists in the world, Thomas R. Holtz, Jr., routinely goes out of his way to explain why birds are now considered dinosaurs even in newspaper interviews, not to mention books for general audiences.[1] Dinoguy2 (talk) 13:43, 12 June 2009 (UTC)

Dino guy. Un-period, un-end. You have a strange blunt way of conversing here. My post was specifically aimed at the the term "most paleontologists today regard birds as the only surviving dinosaurs" (it did not say most published paleontologists) and I instantly found this not to be true at one location. Those paleontologists do not only talk to the average person this way they talked to themselves this way. Only when talking cladistics do they talk your way but cladistics is not the norm for them when describing dinosaurs. As I said I will talk to some more in the coming weeks and see if that status is maintained. I just ask simple questions to make it easy on them: are birds dinosaurs? are birds descended from dinosaurs? might birds be descended from dinosaurs? how do you describe birds/dinosaurs cladistically? In a two page encyclopedia would you use cladistics in describing birds and dinosaurs? So far I only did this once as I said from the beginning, but I'm willing to try a few more times to see how it falls out. Most are too close to this article to really give an objective viewpoint, so I'll ask around without mentioning wikipedia. Fyunck(click) (talk) 21:43, 13 June 2009 (UTC)

Asking around at museums is original research, isn't it? It's got to be published to be verifiable. And surely this encyclopedia article is longer than two pages, so why would you ask them about a two-page encyclopedia? Firsfron of Ronchester 22:26, 13 June 2009 (UTC)

If I plan on including what someone says in this article then yes that would be original research which is a wiki no-no. If someone makes a general statement here under the talk section that everyone is saying a certain thing and I personally check it out and find it to be incorrect I can certainly write here that it was a false statement. This would call into question other things written in this article that the original person had written here and maybe make new readers doubt the sources and check things out for themselves. Let me reiterate that I only have one area source and I made a simple statement based on that one place. That's why I wanted to check out a few more. The new sources may back the original statement.... then again they may not. Fyunck(click) (talk) 23:24, 13 June 2009 (UTC)

I applaud the fact that you're going to museums and asking questions. Few people do this (and if you go, would you mind taking some photos of specimens? We could use them in articles that still need photos). But whatever your result is, it can't have an impact on this article, because this article requires published citations, preferably from peer-reviewed sources. Philcha, below, has cited sources for the claim (if the existing ones weren't enough to satisfy you). You could also go to your library and check out a copy of The Dinosauria, second edition, which contains the work of 50 paleontologists; the theropod portions (pages 25-231) and others consistently include birds as a clade of Theropoda. Firsfron of Ronchester 00:32, 14 June 2009 (UTC)

You need to be specific on what you might want photos of and I'll certainly snap a few and upload them. On the other issue I have found throughout wikipedia that there is far too much "carefree" use of the terms most, many, fact, etc... When I see in the header "The 10000 living species of birds may be classified as dinosaurs", when in this talk page you wrote "most paleontologists today regard birds as the only surviving dinosaurs"... those are huge red flags in an encyclopedia. I saw the sources and I was not swayed to the degree that I could write those statements in this encyclopedia. So I simply wanted some of my own first hand experience so that I could judge how well written and factual this article might be. After one brief encounter I now have some doubts as to the bias of some statements written in this article but I want to make sure those doubts are warranted, hence a little more work on my part is needed. This doesn't mean I would do anything at all to this article regardless of what I find... it's not my field. Overall I find this entry well written and easy to understand, but if for example I found that certain statements are biased or untrue it would affect what I tell students about this site or what I might later write about the validity of wiki articles in general or this article in particular. While I have some geology in my background, paleontology is just a minor hobby that I find fun from time to time which is why I came here to begin with. And it's not like this article is horribly biased as say, the global warming entry is. That one is a hopeless mess. This just had a couple things that made me wonder so I thought I would check it out on my own to give me a better understanding of the situation. Fyunck(click) (talk) 01:11, 14 June 2009 (UTC)

Regarding pictures, most of the most popular, "big name" dinosaurs already have several photos. But many of the lesser-known genera still have none. (The most popular genera are at the top of this list). Whatever pictures you can take are greatly appreciated, Fyunck. Regarding this article's bias: it appears to be in line with The Dinosauria 2nd edition, and recent peer-reviewed papers. At any rate, enjoy the museums! Nothing wrong with asking questions. :) Firsfron of Ronchester 13:33, 15 June 2009 (UTC)

Back to basics. There are 2 common classification systems in use, Linnean and cladistics (there were at least a couple of others, but cladistics appears to have driven these to extinction). The Linnean one aims to put organisms in nicely separate boxes by emphasising their differences, while cladistics tries to build a "family tree" by seeking resemblances. The Linnean system was designed for modern organisms, which have mostly diverged significantly from common ancestors (hundreds of) milions of years ago, and can't cope with transitional forms - which quite a lot of fossils are. So paleontologists pay lip service to the Linnean system but use cladistics for the serious work. (this is not WP:OR - see Brysse, K. (2008). "From weird wonders to stem lineages: the second reclassification of the Burgess Shale fauna". Studies in History and Philosophy of Science Part C: Biological and Biomedical Sciences. 39 (3): 298–313. doi:10.1016/j.shpsc.2008.06.004.) In some areas of zoology the Linnean system has broken down, because classifications based on a relatively few subjectively-chosen distinguishing characteristics have been rejected in the last 10-20 years, so that the traditional names are pretty well useless, see e.g. Flatworm and Annelid, and the literature cited there.

So birds really are the surviving dinosaurs. If we went back to the Late Cretaceous and forgot all the paleo articles we'd read, we'd struggle to identify birds as a separate group: feathers appear to have been standard equipment throughout the Coelurosauria, although the bigger species (over 1 ton?) discarded them; toothless horny beaks appear in all sorts of dinosaurs, some only very distantly related to birds; likewise the backwards-pointing pubic bone; etc. --Philcha (talk) 22:21, 13 June 2009 (UTC)

Re cladistics overwhelmingly the main method: Dinosaurs and Birds - an Update (Padian; from a journal); "Defining dinosaurs" Introduction to the study of dinosaurs (pp 7-10).

Re "birds are dinos" being the consensus: Feathered dinosaurs, flying dinosaurs, crown dinosaurs, and the name “Aves” (heavy thoery, but the bottom line is that they are); The Evolution of Dinosaurs (note "excluding birds for the purpose of comparison") Birds are Dinosaurs: Simple Answer to a Complex Problem (an opponent admits it's the consensus!). I think that's enough for now. --Philcha (talk) 00:07, 14 June 2009 (UTC)

I did some original research of my own: At the AMNH, one of the best known, prominent museums in the world with a huge number of visitors. As soon as you walk into the Hall of Saurischian Dinosaurs, you see a display of coelurosaurs including a flock of stuffed seagulls flying overhead and a huge banner in bold letters that states bluntly "Birds Are Dinosaurs." Maybe the paleontologists you're talking to should complain to the museum board about spreading false information or trying to confuse people with cladistics (which is also explained on a nearby wall chart). Dinoguy2 (talk) 22:11, 14 June 2009 (UTC)

Maybe... of course I didn't look at charts.... I felt asking the scientists themselves would be better. Fyunck(click) (talk) 06:33, 15 June 2009 (UTC)

Well if the museum scientists are all disagreeing with what the official museum materials and displays state, how reliable can the museum be as a "source"?Dinoguy2 (talk) 15:58, 21 June 2009 (UTC)

Attempts to recreate dinosaurs

Why is there no mention of scientists trying to recreate dinosaurs? There have been numerous attemps by scientists, yet I have found no mention of this on Wikipedia at all. Attempts include creating dinosaurs from DNA taken from ancient mosquitoes frozen in amber (which inspired Jurassic Park) (disproven when the DNA samples were discovered to have been contaminated milions of years ago), creating them from stem cells that survived million of years (disproven when realize they would never be capable of finding the number of stem cells needed), or retro-engineering birds to give them dinosaur-like characteristics (it has been proven that this is possible through experiments with mutliple animals species, such as flies an rabbits). 174.130.12.126 (talk) 22:01, 7 September 2008 (UTC)

Because none of those things ever happened? There have been no serious, credible attempts to recreate dinosaurs. What you list is a series of media misrepresentations and misinterpretations of actual work that never had such a silly purpose. To quote a blog I read, recreating a dinosaur is like "trying to knit a Lambourgini out of steel wool". Mokele (talk) 22:33, 7 September 2008 (UTC)

What's missing from the article is an account of earlier attempts to amplify dino DNA, mostly for taxonomic purposes, and the debunking of this possibility by Cooper and colleagues. This may or may not be a reasonable starting point (don't have journal access from this computer). (Iirc Cooper and colleagues concluded that anything older than 100,000 years was definitely beyond recovery. That may or may not be the latest news in that debate.) Papa Lima Whiskey (talk) 11:46, 12 September 2008 (UTC)

To even consider such a thing is just a freak show.--Streona (talk) 17:17, 22 September 2008 (UTC)

Somebody watched Jurassic Park way too many times. —Preceding unsigned comment added by Jdlund (talk • contribs) 01:09, 1 October 2008 (UTC)

you know some one should put that we might be able to really clone dinosaurs by taking a large or medium-sized bird and go backward, by giving it a tail, teeth, arms, ahdns and fingers and making a dinosaur from that, does the show "Dinosaurs: Return to Life" ring a bell —Preceding unsigned comment added by Aslan10000 (talk • contribs) 02:34, 17 December 2008 (UTC)

Can I revive this discussion? Something like this has such wide-ranging popular appeal that it should be discussed in the article. contributions especially welcome from anyone who's read Horner's new book. Abyssal (talk) 15:28, 12 June 2009 (UTC)

Why Triceratops?

Under 'modern definition', it says "Under phylogenetic taxonomy, dinosaurs are usually defined as all descendants of the most recent common ancestor of Triceratops and modern birds." Why Triceratops in particular? It would be nice to explain this better. The cited source doesn't explain, unless I'm missing something.The Drama Llama (talk) 20:16, 11 September 2008 (UTC)

Any ornithischian dino would do, it's just that Triceratops is the most charismatic and one of the easier ones to spell. That answer may look flippant, but it's pure plain truth. -- Philcha (talk) 20:37, 11 September 2008 (UTC)

So... is this some kind of 'official' definition or not? The whole thing seems odd to me (as a non-expert) and could do with clarifying.The Drama Llama (talk) 22:36, 11 September 2008 (UTC)

It's all to do with cladistics. A monophyletic clade (group) is all the descendants of a single commom ancestor, plus that common ancestor. The definition "dinosaurs are usually defined as all descendants of the most recent common ancestor of Triceratops and modern birds" assumes that: dinos are a monophyletic clade; all the descendants of their last common ancestor are either saurischians or ornithischians (this is the dubious assumption, IMO, as there are several "basal" dino genera, e.g. Staurikosaurus, Hererrasaurus); Triceratops is the last member of its branch of the ornithischian lineage (reasonable); birds are the last members of the saurischian lineage (almost certainly). But "... of the most recent common ancestor of Tyrannosaurus and Edmontosaurus" would also be good enough, as these are/ were the last members of their branches of the saurischian and ornithischian lineages respectively. You'll see what I mean if you have a look at Dinosaur#Classification and see what these two possible definitions include - they're equivalent. Philcha (talk) 23:14, 11 September 2008 (UTC)

PS my flippant comment above was too flippant in one respect - only the latest member of any group of ornithischians would do. So for example Triceratops is a good choice for ceratopsians but e.g. Protoceratops would be a poor choice as it may be the ancestor of many later ceratopsians, which would be excluded if the definition used Protoceratops for the ornithischian lineage. -- Philcha (talk) 23:20, 11 September 2008 (UTC)

That's not really correct--assuming the basic split between saurischians and ornithischains is right, literally any ornithischian of fairly certain classification would do fine. Protoceratops, Hypsilophodon, etc. A competing defintion uses Megalosaurus and Iguanodon, the first ornithischian and saurischian described. Whether basing the definition on latest-surviving (Triceratops, Passer), historical, etc. is a matter of taste only. Actually, the PhyloCode has a provision stating original intent trumps other definitions, so Iguanodon+Megalosaurus (maybe also + Hylaeosaurus) will probably become the official definition when that goes into effect in a few years. Dinoguy2 (talk) 00:28, 12 September 2008 (UTC)

Stygimoloch ?--Streona (talk) 23:29, 11 September 2008 (UTC)

OK, that makes sense and thanks for explaining. But wouldn't it be better to say something like "dinosaurs are usually defined as all descendants of the most recent common ancestor of the last ornithischians and modern birds"? It seems less random, and easier to understand for the layman, as it otherwise risks suggesting that Triceratopses are somehow special.The Drama Llama (talk) 00:25, 12 September 2008 (UTC)

That's not a bad idea, and actually I'd make it "ornithischians and saurischians (including birds), specified in official definitions by representative embers of each group, for example Triceratops + ..." etc. etc. Dinoguy2 (talk) 00:37, 12 September 2008 (UTC)

Species counts

I'm not sure whether this material would belong here, or in Dinosaur classification, so raising it for a decision by those more knowledgable of how Wikipedia is covering the topic. This BBC News/Science article discusses an article in the journal Biology Letters that is on the accuracy of species counts and number of species. There is apparently (see paragraph 2) a controversy in the field about the number of species and the degree to which modern "new species" are truly newly discovered versus new names for old species. It does say that there have been 1,047 names given for dinosaur species from 1824 to the present, duplication has reduced the number to 500 or so now considered species, and that new species are currently being described about once a fortnight. All of this looks like material that Wikipedia ought to cover - but where, and can someone with access to the relevant journals (not me) use them as sources? GRBerry 14:44, 17 September 2008 (UTC)

I'm guessing they're taling about the new Benton paper? It's available free here: [2] currently first line under 2008. Dinoguy2 (talk) 01:03, 18 September 2008 (UTC)

The BBC article does focus on that paper, yes. But I wouldn't want to add here without at least reading the other papers on error rates with which Benton is disagreeing. And where should it go? GRBerry 02:44, 18 September 2008 (UTC)

dinosaurs are cool —Preceding unsigned comment added by Shaneh16 (talk • contribs) 11:06, 18 September 2008 (UTC)

I had found the BBC article on my own and added it to the article before I read the talk page. I'll trust the editors here to keep or remove it. Grundle2600 (talk) 16:59, 18 September 2008 (UTC)

Air sacs, etc.

Well done for finding the Areosteon article, User:Craigsjones!

I think some re-structuring is in order. Dinosaur now has related material in sections "Physiology" and "Feathers and the origin of birds:Soft anatomy" (which follows but should support the metabolic stuff in "Physiology"). "Physiology" deals only with metabolism but is rather long. I therefore suggest:

Feathers (w/o birds)
A single section "Physiology" structured something like Physiology of dinosaurs, with metabolism the last sub-section as it uses many of the others.
Origin of birds, which will use previous material relating to feathers and physiology.
If any of these sections / sub-sections looks too long, move excess material to Physiology of dinosaurs if it's not already covered there. -- Philcha (talk) 07:52, 30 September 2008 (UTC)

interwiki link

Please Add Inter wiki link to telugu article te:డైనోసార్. Thanks

రవిచంద్ర (talk) 04:42, 8 October 2008 (UTC)

Done OhNoitsJamie ^Talk 04:49, 8 October 2008 (UTC)

interwiki FA

Someone should add the Link FA|ca , thanks--Ssola (talk) 22:17, 27 October 2008 (UTC)

Done. Congratulations! J. Spencer (talk) 22:50, 27 October 2008 (UTC)

A few edits to the intro

I've made a few changes to the intro paragraphs, mostly to address some flow and word choice issues. Cheers, Killdevil (talk) 23:00, 5 November 2008 (UTC)

In this edit the change from "Most research ... has supported the view that dinosaurs were active animals with elevated metabolisms".. " to "Nearly all ..." is an exaggeration. The previous "since the 1970s" was also more future-proof than "in the last 40 years". --Philcha (talk) 23:01, 5 November 2008 (UTC)

Hmm, OK -- I just revised things a bit to address your comments. Killdevil (talk) 03:20, 6 November 2008 (UTC)

Some edits to the "Cultural Depictions" section

I've made some changes to the "Cultural Depictions" section. Cheers, Killdevil (talk) 00:51, 21 November 2008 (UTC)

Cool. Feel free to borrow from the main article, 'cause it's a GA now. J. Spencer (talk) 02:56, 21 November 2008 (UTC)

Failure to adapt to changing conditions?

We now have a subchapter with this content:

Lloyd et al (2008) noted that, in the Mid Cretaceous, the flowering angiosperm plants became a major part of terrestrial ecosystemss, which had previously been dominated by gymnosperms such as conifers. Dinosaur coprolites — fossilized dung — indicate that, while some ate angiosperms, most herbivorous dinosaurs mainly ate gymnosperms. Statistical analysis by Lloyd et al concluded that, contrary to earlier studies, dinosaurs did not diversify very much in the Late Cretaceous. Lloyd et al suggested that dinosaurs' failure to diversify as ecosystems were changing doomed them to extinction.

However, the study in question concluded that there was no proof of any progressive decline at the end of the Cretaceous. True, the paper ended — and this was the only sentence which might be construed to entail the suggestion mentioned in the subchapter — with the ominous words Hadrosaurs and ceratopsians showed late diversifications, but not enough to save the dinosaur dynasty from its fate., but pointing out the obvious fact that any adaptation to the eating of angiosperms was not enough to ensure the continued existence of most dinosaur clades in the face of, e.g., a giant bolide impact should not be taken as implying that a lack of it somehow was a major cause of their extinction; after all the paper states: The patterns of rises and falls in the diversity of Cretaceous dinosaurs and Cretaceous plants, as well as their palaeogeographic distributions, do not suggest any correlation.--MWAK (talk) 18:26, 4 December 2008 (UTC)

Birds and Time Periods

I, like all of you, want to improve this article and I say we should remove the parts of dinos-birds and the time periods. Due to us not knowing the exact time we should not tell the reader the age but the general information. I also say this because of cryptozoology.69.23.218.70 (talk) 01:46, 18 December 2008 (UTC)

Well, if you have some reliable sources that verify what you state here, please go for it. And Cryptozoology is a fringe theory, and we cannot give undue weight to such theories. OrangeMarlin ^{Talk• Contributions} 01:49, 18 December 2008 (UTC)

If one wants to improve the article, one should not replace science by pseudo-science.--MWAK (talk) 10:57, 29 December 2008 (UTC)

In Question

The article says "Under phylogenetic taxonomy, dinosaurs are usually defined as all descendants of the most recent common ancestor of Triceratops and modern birds.It has also been suggested that Dinosauria be defined as all of the descendants of the most recent common ancestor of Megalosaurus and Iguanodon, because these were two of the three genera cited by Richard Owen when he recognized the Dinosauria." What are all the other species recognized nowadays as dinosaurs, then? What about the sauropods and the non-maniraptorian or allosaurian theropods, the ankylosaurians, stegosaurians, and non-iguanodontian ornithopods? They aren't descendants of Triceratops or birds or Iguanodon or Megalosaurus. That kinda needs revision, 'cause it's contradicted by the following statement: "Both definitions result in the same set of animals being defined as dinosaurs, including theropods (mostly bipedal carnivores), sauropodomorphs (mostly large herbivorous quadrupeds with long necks and tails), ankylosaurians (armored herbivorous quadrupeds), stegosaurians (plated herbivorous quadrupeds), ceratopsians (herbivorous quadrupeds with horns and frills), and ornithopods (bipedal or quadrupedal herbivores including "duck-bills")." —Preceding unsigned comment added by 142.26.133.248 (talk) 18:33, 5 January 2009 (UTC)

"Descendants of the most recent common ancestor of" is the key phrase here. The most recent ancestor held in common by a Triceratops and a turkey, or a Megalosaurus and an Iguanodon, is also the ancestor of those other dinosaurs. If the chosen animals were a Deinonychus and a Velociraptor, you'd get a much smaller set, because the most recent common ancestor of those two is not the ancestor of any dinosaur outside of some dromaeosaurids. If the chosen animals were Triceratops and Tanystropheus, the most recent common ancestor of those two would also have led to crocodilians, phytosaurs, aetosaurs, and a bunch of other things. J. Spencer (talk) 22:57, 5 January 2009 (UTC)

More finicky - should it not be "the most recent common ancestor of Triceratops and modern birds, and all its descendants", i.e. the LCA must also be a dino? Otherwise I think the definition would allow polyphyletic dinos if one offspring of the LCA was the first saurischian and another was the first ornithischian. --Philcha (talk) 23:16, 5 January 2009 (UTC)

For some reason I found that hilarious, even though it is true by definition that the first generation after the LCA has to include the first saurischian and the first ornithischian. J. Spencer (talk) 02:23, 6 January 2009 (UTC)

At any rate, it was a good catch, because the citation didn't cover the material cited. J. Spencer (talk) 02:34, 6 January 2009 (UTC)

Could you please explain to me my unintended joke? :-)

While looking unsuccessfully for the joke myself, I was reminded of why I'm not keen on phylogentic definitions. For example the definition given does not allow for a third lineage descended from the LCA (possibly just "other basal dinos"), nor for multiple "generations" (e.g. chronospecies) of clearly basal dinos before the saurischians and ornithischians diverged. --Philcha (talk) 11:18, 6 January 2009 (UTC)

The funny wasn't all that funny, just something in the way I was thinking about the first saurischian and the first ornithischian. It's like the parents looking at the hatching eggs and saying, "Okay, you are the ornithischian, and you are the saurischian." J. Spencer (talk) 01:16, 7 January 2009 (UTC)

That's just the way the definition was set up: as a node/stem triplet. All dinosaurs must either be a saurischian or ornithischian. Anything that isn't, isn't a dinosaur. That was done to preserve traditional content. All those links leading up to the split are covered under Dinosauriformes (lagosuchians, silesaurs, etc.). By "clearly basal dino" you're using a morphological, not phylogenetic definition. In cladistic terms, any series of chronospecies leading up to the split will clearly be non-dinos. (Or, depending on how you define species, would all be the LCA and so be included). Of course, you could always define dinosaurs as a stem, rather than a node (say, all species closer to Megalosaurus than to Lagosuchus), which would include many species before the saur-ornith split. Either way is arbitrary, but one way guarantees you get all the traditional dinosaurs, while with the other, there's always a slim chance ornithischians could turn out to be non-dinosaurian. As it stands, there's a very slim chance sauropods could be non-dinosaurs, since they're not named in the node definition, but they were originally considered crocodiles anyway ;) Dinoguy2 (talk) 22:59, 6 January 2009 (UTC)

"Etymology: Really?" or "Yumm, That New OR Smell!"

Ok, currently in the Etymology section, there is an unsourced statement that has the suspicious stink of OR (very light on the "R" no doubt), which claims that the colloquial use of the word "dinosaur" to describe "an obsolete or unsuccessful thing or person" (this phrase is sourced to Mirriam-Webster, which does not mention the following) "became common while dinosaurs were regarded as cold-blooded and sluggish." While no doubt literally true, the implication is that the reason "dinosaur" denotes something obsolete or unsuccessful is because they were thought to be sluggish. It seems to me, however, highly more likely that, although dinosaurs were wildly successful in their day, we've come to use the word to mean "obsolete or unsuccessful" merely because dinosaurs are by far the most famous group of animals that have gone extinct (there it may be relevant to note that this use probably began before we knew that birds are dinosaurs). The word "obsolete" here rings the Obvious Bell especially loudly -- what does "obsolete" have to do with being sluggish or cold-blooded? It may be that our notion of the word dinosaur in this usage is informed by both explanations. Certainly one may describe an old codger, to whom it would be appropriate (though inconsiderate) to apply the term, as both "old" and "dying out" as it were, as well as "cold-blooded" and "sluggish". Certainly some overlap there. While I would like to rewrite this little sentence (doing so would have been a lot easier than all this), I'd be remiss if I wiped someone else's OR only to substitute my own, and right now I don't have access to any kind of etymological dictionary, much less one that would have good research on a modern colloquial usage like the one in question. So... anyone? —Preceding unsigned comment added by Torgo (talk • contribs) 16:51, 3 January 2009 (UTC)

I removed the commentary, as I have no idea when or how the secondary usage came into being. I suspect it's probably more due to their being dead, though. J. Spencer (talk) 19:30, 3 January 2009 (UTC)

Proof?

Off-topic discussion concerning religious beliefs that gets reopened every couple of months. Remember that Wikipedia is not a soapbox or a forum.

The following discussion has been closed. Please do not modify it.

Where is the evidence concerning the point that dinosaurs lived over 65 million years ago? This is not proven, and should not be in the article unless there is hard evidence regarding it. —Preceding unsigned comment added by 86.155.202.11 (talk) 18:46, 3 January 2009 (UTC)

Yeah, I agree. How can anyone really KNOW about things that happened before people existed? And don't give me all that carboxic dating stuff. It's never been proven to work. People just love to try and tear down other people's beliefs. Hey geniuses, God was there. HE did it, HE would know. 161.130.178.151 (talk) 23:58, 22 January 2009 (UTC)

I also agree. Carbon dating doesn't prove anything. It's completely inaccurate. Either way, we don't need carbon dating to figure out how old the earth is. Humans have been on the earth since it was created (by God). The earth is about 6000 years old. —Preceding unsigned comment added by 12.227.138.94 (talk) 15:45, 1 May 2009 (UTC)

It would be slightly easier to take you seriously if you did enough research to know a) the name of the dating system that you're attacking (I assume you're referring to carbon dating, as there is no such thing as carboxic dating) and b) that carbon dating is not used with dinosaurs, as its half-life is far too short. The age of dinosaur-bearing rock formations are typically dated via a combination of uranium-lead and argon-argon systems for absolute dates of igneous rocks found above or below the fossil-bearing sedimentary rocks (typically ash beds and thin volcanic basalt flows), and marine invertebrate fossil correlations and paleomagnetic chronology for relative dating. Additionally, this article is about dinosaurs, whereas your issues are apparently not about dinosaurs, but nuclear physics and radioactive decay, basic laws of geology, and a god who apparently decided to fake an internally consistent old earth, so I'd recommend raising your questions at those articles instead. J. Spencer (talk) 00:46, 23 January 2009 (UTC)

Or better yet, don't; these talk pages are not forums. Abyssal (talk) 16:16, 1 May 2009 (UTC)

Whether you choose to believe in God or not, 65 million years is NOT proven fact. Carbon dating, although not used as the main dating method was used once(or maybe more) to date fossils. It was found that all the fossils had carbon. Enough to be picked up by that "Dating Method". Pretty hard to believe 65 million years when that happens. And since you know nothing about God, a "god who apparently decided to fake an internally consistant old earth" doesn't even make sense. The Bible explains the past that scientists today completely ignore, and the "Old Earth Theory" only came into existance roughly 200 years ago, while the rest of the world knew there was only 6000 years of human history, let alone no document ever found that goes "before" the events the Bible says were the beggining. The Earth went through events that changed it. Scientist ignore the changes and pretend everything was the same since the beggning, then obviously there gonna get the wrong conclusions. If you date the Earth without adding those facts and ignoring the main fact that God created an "old Earth" and didn't start by bringing in rock debris until it forms, then what do you expect to believe? Whos at fault if they ignore the facts God gave to us, then blame Him because He didn't conform to our dating method by making the Earth look "young" so we can believe Him? Mwarriorjsj7 (talk) 00:43, 31 May 2009 (UTC)

You seem confused about the presence of carbon and how it relates to the use of radiocarbon dating. One cannot simply date any carbon that is present. Carbon dating relies on the presence of the isotope carbon-14, which stops being accumulated in an organism when it dies. The carbon-14 then undergoes radioactive decay, which it does at a rate that makes it undetectable relatively quickly. Thus, carbon dating doesn't work for anything that doesn't have measurable amounts of C-14.

You might want to brush up on comparative religions and the history of science. In particular, you'll want to do some research before you try "the rest of the world knew there was only 6000 years of human history" on, for example, a Hindu.

And before anyone else digs up this section again, have a look at WP:TALK and remember that Wikipedia is not a soapbox or forum. This page is for discussing improvements to the Wikipedia article Dinosaur. Tangents about how personal religious beliefs interpret accept or do not accept various areas of modern science are not included in that mandate. If someone doesn't accept evolution or an old earth, a) they're wasting their time trying to attack it on a talk page and b) this is the wrong article anyway. J. Spencer (talk) 02:50, 31 May 2009 (UTC)

Intro

I've played about with the intro slightly. I think the bird discussion, whilst important, seems a bit of a digression coming as it does in the second paragraph. There should be a more general discussion of what dinosaurs were before this talk of their ancestry. As this is a featured article I've attempted to rearrange rather than rewrite too much. Pretty Green (talk) 09:03, 9 February 2009 (UTC)

I was thinking of making this change myself. Good stuff. While we're talking about the intro, does anyone share my sense that it could benefit from a sentence or two addressing the physical characteristics of dinosaurs? We say near the beginnning that they were the dominant vertebrate animals of terrestrial ecosystems, we say they were active and warm-blooded, and down below we compare them with birds, crocodilians, and other archosaurs... but I'm not sure that's enough. Killdevil (talk) 21:36, 10 February 2009 (UTC)

I think a more general overview of characteristics in the intro, removing something from the birds/crocodiles/archosaurs bit if necessary would improve how this reads. --Pretty Green (talk) 09:28, 11 February 2009 (UTC)

Museum posture

I did this update here while trying to get an item put in In the news on the main page.--Chuck Marean 03:34, 28 May 2009 (UTC)

Would it make more sense in the sauropod article, given they're the main subjects of the paper? J. Spencer (talk) 04:14, 28 May 2009 (UTC)

I reverted that edit. This isn't wikinews, and not every news story about dinosaurs belongs in an encyclopedia article. If this becomes a more notable dispute, then perhaps. --ZimZalaBim ^talk 05:48, 28 May 2009 (UTC)

Small missing word

"their erect stance, is now known to have present" should be : "their erect stance, is now known to have been present"

216.162.78.131 (talk) 03:39, 4 June 2009 (UTC)

Luc D.

Fixed, thanks for letting us know! Maedin\^talk 07:00, 4 June 2009 (UTC)

I am going to feel inane saying this

Is the reference to Godzilla in the cultural references section accurate? Is he supposed to be a dinosaur, or merely a monster? I was under the impression that since the article, from the beginning, refers to reptilian dinosaurs in the past tense ("Dinosaurs...were the dominant vertebrate animals..."), then a contemporary massive reptile wouldn't be a dinosaur. Sure, there's the reference to the fact that "The 10 000 [sic] living species of birds may be classified as dinosaurs.", but is a mutated iguana (mind you, it refers to the Godzilla films), which is what the 1998 version states his origins as, a dinosaur? Also, that "10 000" thing needs a comma. NeutronTaste (talk) 02:18, 21 June 2009 (UTC)

10 000 doesn't need a comma; it supposed to be that way so that both European readers and American readers can tell what the number is (Europeans use a period in place of a comma). Firsfron of Ronchester 02:24, 21 June 2009 (UTC)

But yep... Godzilla was supposed to be a dinosaur. I remember the lines in the original movie pretty well. The scientist from Japan says that in the mesozoic era there was an intermediary species ... a cross between a land dwelling and sea dwelling animal. Thus Godzilla. He may have been mutated a bit because they found plenty of strontium 90 wherever Godzilla walked, which they say was a product of the H-Bomb. Also in Godzilla's footprints along the shore they found living trilobites. Strange combo. Fyunck(click) (talk) 05:20, 21 June 2009 (UTC)

Fair enough. I wasn't aware of the comma/period difference. Thanks for the explanation regarding the Godzilla info, it has been ages since I've watched the original films and I couldn't recall anything about his dino-status from those films. NeutronTaste (talk) —Preceding undated comment added 07:37, 21 June 2009 (UTC).

How was it established that dinosaurs are reptiles?

Yes, I know that the word "dinosaur" itself means "terrible lizard" and there have been countless movies made depicting them as reptiles; but I would like to know how they figured that out. As far as I'm aware, there are a few characteristics of reptiles: cold-blooded, scales covering the body, lay amniote/leathery eggs, three-chambered hearts (with the exceptions of crocodiles and alligators) - most of which can't be determined by a study of the bones or fossils of these creatures. The dinosaur egg article on wiki says that some dinosaur eggs resemble bird eggs, which means they have a hard calcite covering, which is the opposite of what you would expect from a reptile.. can anyone please clear? Dorkness (talk) 16:07, 22 July 2009 (UTC)

As far as I know, it was first done by studying teeth. Skeletal features, especially teeth, are much more useful for classifying animals than the characteristics the general public is most familiar with, which you list. Specifically, anatomists noted the close similarity between the teeth of the first known dinosaur and the modern iguana, hence the name Iguanodon. And, by the way, having a hard shelled egg or warm blood doesn't preclude something from being a reptile. In modern classifications, birds are reptiles too. Dinoguy2 (talk) 23:54, 22 July 2009 (UTC)

Well if that's true and the dental structure is how they are grouped under the class of Reptilia, it still leaves some unanswered questions. Do all dinosaurs have similar dental structures, that they can all be grouped under reptiles? The teeth of a T-rex or a velociraptor might resemble those of a reptile, but what about a herbivore, like a brachiosaurus or a triceratops? Won't their teeth be markedly different from carnivorous dinosaurs, and hence unqualified to be called a reptile?

Also, wiki lists creatures like crocodiles, dinosaurs etc under the class Reptilia, while birds are listed under the class Aves; so paleontologists might be guessing that birds might be related to reptiles, but they certainly can't be grouped under reptiles, even if they are related to them. Also, wiki answers says that reptiles, by definition, are cold-blooded [5]. In summary, there are several irreconcilable differences between birds and reptiles: they are warm blooded, have a four-chambered heart, hollow bones and feathers, among other things.

It's true that scientists have tried to draw a link between reptiles and birds using things like the archaeopterix fossil. However, it has been suggested that Archaeopterix is a complete bird, and not a link between reptiles and birds. Noted Paleornithologist, Alan Feduccia supports this claim. In his own words:

"Paleontologists have tried to turn Archaeopteryx into an earth-bound, feathered dinosaur. But it's not. It is a bird, a perching bird. And no amount of ‘paleobabble’ is going to change that."

(Archaeopteryx: Early Bird Catches a Can of Worms by V. Morell, Science 259(5096):764–65, 5 February 1993.)

"Archaeopteryx probably cannot tell us much about the early origins of feathers and flight in true protobirds because Archaeopteryx was, in a modern sense, a bird."

(Science 259:790-793 (1993))Dorkness (talk) 05:56, 23 July 2009 (UTC)

Evolution isn't a sudden process: it's very slow. Animals don't go suddenly from one taxonomic class to another; a statement like "wiki lists creatures like crocodiles, dinosaurs etc under the class Reptilia, while birds are listed under the class Aves; so paleontologists might be guessing that birds might be related to reptiles, but they certainly can't be grouped under reptiles, even if they are related to them" misunderstands the relationship between Wikipedia and paleontology. Wikipedia articles may discuss paleontological aspects, but cannot serve as a basis for paleontological study. No one in his right mind is going to use Wikipedia as a source for the basis of scientific classifications in a formal paper. Feduccia's view on dinosaurs is a minority view in paleontology. "Irreconcilable differences" here just means "I don't want to reconcile them", not really "they can't be reconciled"; they've already been reconciled by mainstream paleontology. Best, Firsfron of Ronchester 06:48, 23 July 2009 (UTC)

By the way, Wiki Answers is flat-out wrong in that respect. It should specify that only modern reptiles are cold-blooded, and this is not part of any official definition of the group. Not only that, but some modern reptiles are functionally warm blooded, like sea turtles.

"In summary, there are several irreconcilable differences between birds and reptiles: they are warm blooded, have a four-chambered heart, hollow bones and feathers, among other things."

All those things can be said about many dinosaurs, too. All dinosaurs likely had 4-chambered hearts, based on fossilized soft tissue (in fact, crocodiles have 4-chambered hearts too). All saurischian dinosaurs (and all pterosaurs) had hollow bones. All maniraptoran dinosaurs have feathers. There is no fine line between reptiles and bird. All these characteristics appeared in different groups along the way in reptile/bird evolution. Dinoguy2 (talk) 16:52, 23 July 2009 (UTC)

Science is moving away from the Linnaean way of classifying creation: something is either A or B. According to this thinking, Archaeopteryx is either a bird, or it isn't. Dinosaurs are reptiles, or they are not. But classification is a human invention, imposed, if you will, upon the living world. As we learn more and more about the world, we learn that things do not so easily fit into the boxes we make for them. It may be that in time, we will not use the traditional terms 'Reptilia', 'Mammalia', 'Aves', etc, at all.--Gazzster (talk) 07:19, 24 July 2009 (UTC)

Extinction section needs review

Someone who knows more than I should perhaps review the Extinction section. It seems inconsistent with the main article at "Cretaceous–Tertiary extinction event".

The Extinction section currently reads in part:

"Non-avian dinosaurs suddenly became extinct approximately 65 million years ago. Many other groups of animals also became extinct at this time, including ammonites (nautilus-like mollusks), mosasaurs, plesiosaurs, pterosaurs, herbivorous turtles and crocodiles, most birds, and many groups of mammals.[16]"

But the K-T event section doesn't seem to agree about the herbivorous turtles and crocodiles, and the "most birds" claim is apparently controversial due to poor fossil record. A paleontologist friend of mine writes: "As far as I know, mammals, turtles and crocodilians were generally not too badly affected by the extinction. The impact on birds, which have a generally poor fossil record, is controversial."

The K-T Event section includes this:

"Over 80% of Cretaceous turtle species passed through the K-T boundary. Additionally, all six turtle families in existence at the end of the Cretaceous survived into the Tertiary and are represented by current species."

and this:

"Approximately 50% of crocodilian representatives survived across the K-T boundary, the only apparent trend being that no large crocodiles, such as the giant North American crocodile Deinosuchus, survived."

and this:

"All major Cretaceous mammalian lineages, including monotremes (egg-laying mammals), multituberculates, marsupials and placentals, dryolestoideans,[59] and gondwanatheres[60] survived the K–T event, although they suffered losses." —Preceding unsigned comment added by NessBird (talk • contribs) 06:46, 19 August 2009 (UTC)

I'm not sure what the disagreement is, maybe just in the phrasing. The Dinosaur article does say "herbivorous crocodiles" and probably should say "most groups of birds." Only one bird group, the neornithes, made it through, while many orders of enantiornithes, hesperornithes, etc. did not. It's true that the bird fossil record is scrappy at this time and that we can't be sure how many species of, say, neornithes were wiped out, but almost all the bird fossils we do have are enantiornithes, implying that they were the most numerous and diverse bird group at the time, and they were completely wiped out. It's whether and how much neornithes had diversified before or after the event that's controversial. The dinosaur article seems to be talking about overall diversity, while the K-T (why hasn't this been corrected to K-Pg yet?) article is getting down to specific numbers of species. Also, there are errors even in the bits from K-T that you quoted, including mentioning Deinosuchus, which was extinct before the Maastrichtian and was not present for the K-T extinction event. Dinoguy2 (talk) 18:54, 19 August 2009 (UTC)

Some suggestions:

Avoid taking sides on the causes. It seems that the killing mechanisms were largely the same irrespective of whether the cause was the Decaan Traps or the bolide or acobination.
Summarise the pattern of extinction & survival briefly. Mention invertebrates, plants and planktonic organisms as well as vertebrates. IIRC ammonites were already in severe and possibly terminal decline, so there may be scope for a temporal dimension.
A lot more more about the extinction specifically of dinos, e.g gradual or abrupt. --Philcha (talk) 22:41, 19 August 2009 (UTC)

Well, the entire page of "Dinosuar" was chock full of only the evolutionary view of dinosuars. For instance, it speaks of the "millions of billions of years" theory as though it were a fact. Scientists cannot prove that dinosaurs are from a period that happened billions of years ago, or even that these lizards did or not exist at the same time as humans, because, in fact, science cannot prove anything. I believe that this page is in need of some seious changes, such as instead saying "some scientists think that dinosaur evolved millions of years ago, while otheres believe they were created by an intelligent being (i.e. God)afew thousand years ago." That, I think, will fix it nicely, so that it will not seem biased. Rndmizer (talk) 19:10, 5 October 2009 (UTC)Rndmizr

We've been over this a thousand times (see archives above). Wikipedia addresses the views of the majority, and no creationsist views are specific to dinosaurs, but rather the issue is, as you said, with the concept of science itself. If you'd like a dinosaur page to include them, you'd be better off using this cite: [6] rather than Wikipedia. Dinoguy2 (talk) 19:17, 5 October 2009 (UTC)

"the views of the majority" does not adequately describe the flaws in "a few thousand years ago". For "a few thousand years ago" to be true, scientists' of nuclear physics would have to be grotesquely wrong, because that's the only way radiometric dating could be out by orders of magnitude. But then we'd have to explain how most aspects of modern nuclear physics seem to work rather well (including nuclear power, radiotherapy and smoke alarms), yet radiometric dating could be so far wrong. The theory of evolution is supported by other sciences that have proved themselves repeatedly. --Philcha (talk) 19:58, 5 October 2009 (UTC)

"Dinosaurus"

In the Illustrated Encyclopedia of Dinosaurs by David Norman from 1985, a genus called "Dinosaurus" is listed under dubious prosauropod genera. But I have never heard of this genus anywhere else, and I redirected "Dinosaurus" to this article long time ago before reading about the genus. Does anyone know what it is and if it should be mentioned anywhere on Wikipedia? FunkMonk (talk) 14:44, 6 October 2009 (UTC)

Dinosaurus is a junior synoynm of Plateosaurus, isn't it? Dinoguy2 (talk) 17:13, 6 October 2009 (UTC)

Actually apparently that was preoccupied and it's a therapsid...? Will look into it more and get the redirect pointed where it needs to go. [7] Dinoguy2 (talk) 17:18, 6 October 2009 (UTC)

Ah, I see it redirected to Plateosaurus at one point, but when I found the redirect, it lead to some obscure Polish film. FunkMonk (talk) 17:21, 6 October 2009 (UTC)

Ok, cool. I added a dab to the new Dinosaurus page for the film. Dinoguy2 (talk) 17:56, 6 October 2009 (UTC)

Uh, don't know where I got Polish from... But nice work! Good that something (a new article) came out of this after all. FunkMonk (talk) 17:58, 6 October 2009 (UTC)

General morphology

Wouldn't it be nice to have a section on general morphology? Such a section would explain why dinosaurs only had three claws on the front feet, the problem of dinosaur colour (which oddly isn't mentioned anywhere, apart from it being explained in pretty much every dinosaur book), scales and their shape and distribution, nostril placement, so on and so on. In short, many small, but important, details that are now unmentioned. Maybe it should even have its own article? FunkMonk (talk) 18:32, 29 October 2009 (UTC)

I agree with this, but some of the examples you give might be better placed on the genus/species pages. All in all, I think morphology gets short shrift on far too many Wikipedia articles. Nostril placement in particular could use some detailed treatment, as a lot of research has been done on this, and most images of theropods show the nostrils way off. Innotata 19:07, 29 October 2009 (UTC) —Preceding unsigned comment added by Innotata (talk • contribs)

Hi, FunkMonk, I'm afraid these are over-generalisations, and most of the features you list are specific to particular groups. For example:

Triceratops had short five-hoofed hands and four-hoofed feet. AFAIK sauropods are similar. Eoraptor, often regarded as the most basal dino, has 5 claws per hand.

I'd expect colour to be selected by the environment, e.g. arid habits would favour sandy colours and moist forests would favour greens and brown, with camo patterns in both cases - as tanks have now.

Recent research suggests Diplodocus had the nasal openings were high on the head but the actual, fleshy nostrils were situated much lower down on the snout. OTOH Tyrannosaurus seems to have nostrils right on the snout, as were those of Triceratops. --Philcha (talk) 19:20, 29 October 2009 (UTC)

Well, as far as I know (and this is due to Dinoguy telling me, as well as the artwork of Gregory S. Paul and Robert Bakker, some of the few paleontologists known for their life restorations, being this way), most archosaurs, includig all dinosaurs, would have a maximum of three finger claws, regardless of the number of fingers. Same with the nostrils, they would had been placed at the front of the nares in all dinosaurs. As for colours, that's also a general thing, and should be mentioned just to clear it out to ordinary people, as colour seems to be what paleontologists are aksed about most of the time. FunkMonk (talk) 19:42, 29 October 2009 (UTC)

Correct. The number of digits varies across dinosaur groups, as does the number of claws. But no dinosaurs have more than three claws on the hands, including ceratopsians etc. Most sauropods had no claws on the hands at all save the 1st, spike-like one. Also, it may be possible to know the color or at least patterns for feathered dinosaurs, according to some SVP abstracts and published work on avian feathers. Also, Witmer's work on nostril placement applies to all tetrapods, not just Diplodocids. All tetrapods, with very few exceptions, have nostrils in the extreme anterior and ventral 'corner' of the bony naris, so it applies equally to Triceratops and Tyrannosaurus. See, I guess we do need a genral morphology section! ;) Dinoguy2 (talk) 20:06, 29 October 2009 (UTC)

Yeah, I just uploaded a picture of one of the bird fossils where colour could theoretically be determined[8] (one of the scientists behind the study, Jakob Vinther, is Danish, and studied that head), so I searched this article for mention of colour, but I was surprised to find none, even though every single dinosaur book I've read handled the subject in some way at least. FunkMonk (talk) 20:16, 29 October 2009 (UTC)

Oh, a quite interesting thing by the way, in this comment section[9] Jakob Vinther says that some of the feathers of Archaeopteryx were white, but that it wasn't completely white. That should probably be taken into account by all paleoartists... FunkMonk (talk) 20:44, 29 October 2009 (UTC)

Interesting. In the actual paper he said the fact that no dark pigment was present did not mean they were necessarily white, but needed microscopic study to see whether or not melanocytes were once present but now eroded (and in fact, the type feather of Archie is darkly pigmented, unlike the skeletal specimens). I can't read the link, does it imply he has now looked at Archie feathers and found no evidence they ever had melanocytes? That would be something, and probably a good argument that all those famous skeletal specimens are not referable Archaeopteryx, which is dark in color. Time for a neotype :) The last paper also promised that they're going to be examining the Jehol biota... Nick Longrich has already argued at SVP that the color pattern on Sinosauropteryx reflects life pigment, based on unpublished UV studies. We'll see if Vinther backs that up. I've already restored it with apparent preserved patterning here: [10] Dinoguy2 (talk) 22:07, 29 October 2009 (UTC)

Hmm, I'll translate the bit: "Archaeopteryx has white feather impressions, but was not completely white, one finds impressions of melanosomes, that have been oxided away." A bit unsure what that means now. FunkMonk (talk) 01:05, 30 October 2009 (UTC)

Oh, and also that whole hand pronation issue could be handled in such a section, would be a good myth killer. FunkMonk (talk) 11:17, 30 October 2009 (UTC)

Dinosaur Extinction Causes

As of December 2008, the major differences of professional opinion on the causes of the mass extinctions continue to be between the supporters of the Chicxulub Impact event and those of the Deccan Traps volcanism.

The dispute over the causes of the extinction at the end of the Cretaceous has again come to the fore after the December 2008 meeting of the American Geophysical Union in San Francisco.

There, Gerta Keller of Princeton University emphatically repeated her remarks of 2003. Additional field-work by Keller and her colleagues supports the conclusion that the extinctions happened at the same time as the end of the main phase of India's Deccan eruptions, which points to it being volcanism that killed the dinosaurs.

Keller states: "The Chicxulub impact hit the Yucatan about 300,000 years before the mass extinction that included the dinosaurs and, therefore, could not have caused it." Keller also said that the Chicxsulub crater has been vastly overestimated as evidence. More information on these findings will be released later in 2009.

Contacted after those assertions were made, Walter Alvarez continues to reject the idea of volcanism as the cause of the mass extinctions, saying that other scientists have also, after detailed examination, found it unacceptable and that few experts would agree that Chicxulub is older than the extinctions. As a reminder, he said that it was the discovery of the thin layers of iridium, rare at the earth’s crust but more abundant in meteorites, that triggered his impact theory. And subsequently, around the world, similar debris from a giant impact was identified in sediments deposited at the same time as the mass extinction happened. Alvarez said that volcanism may have played a contributing role but that the Chicxsulub event was the primary trigger.

So where does that leave us? It is well known that many times in the past the Earth has suffered major consequences from the impacts of asteroids and comets that have reached Earth from far out in the Solar System.

I have not heard it expressed elsewhere, but it occurs to me to ask: could Walter Alvarez have located the wrong crater, a crater 300,000 years too old? And is it possible that the real culprit, if it was a meteorite, is still waiting to be found? The combination of the evidence of the Deccan Traps volcanism together with a new discovery of a younger dated catastrophic impact would seem to be the best of both worlds and might even satisfy both camps.

About the object that impacted at Chicxulub, the bolide, scientist David Brez Carlisle, in his book “Dinosaurs, Diamonds and Things from Outer Space” published in 1995 by Stanford University Press, states that the impactor was not an asteroid but a comet of about 20 miles in diameter. This interpretation being based, among other things, on the composition of the non-terrestrial rock materials at the crater site. He provides several pages of valid scientific details to support his conclusion.

Rezansoff (talk) 19:06, 24 January 2009 (UTC)

The "Dinosaur" article, "Impact event" section, says that the Chicxulub crater was "170 kilometers (110 mi) wide" (1st para.) and "175 kilometers (110 mi)" wide (3rd para.). The "Chicxulub crater" article says that it was "more than 180 kilometers (110 mi) in diameter". Could we have some consistency, please?

There also seems to be a problem with conversion of units. How can 110 miles be equivalent to 170, 175 and 180 kilometres?

Old Father Time (talk) 14:17, 22 November 2009 (UTC)

It looks like two things are at play: the crater is not round but oval; and the sizes in this article are probably based on the citations they precede, and we don't know how the publication authors arrived at their figures. With this in mind, I'd be inclined to take either the most recent, or the one from the K—T extinction page (uses 180 km average diameter),^[1] since it is specifically about the crater itself.

^ Pope KO, Ocampo AC, Kinsland GL, Smith R (1996). "Surface expression of the Chicxulub crater". Geology. 24 (6): 527–30. doi:10.1130/0091-7613(1996)024<0527:SEOTCC>2.3.CO;2. PMID 11539331.{{cite journal}}: CS1 maint: multiple names: authors list (link)

Thank you. I've changed the figure to 180 km, but, as you say, this may now contradict the figures given in the two citations used.

Old Father Time (talk) 17:00, 22 November 2009 (UTC)

Okay. I've imported the ref mentioned above to cover the bases, and then removed the second mention of the size on the grounds that it was probably redundant, having been stated a couple paragraphs above. The section was probably "flown in" from another article when the paper came out and was not reconciled with its new home. J. Spencer (talk) 17:07, 22 November 2009 (UTC)

Thank you. One small problem: your emendation uses the British spelling "kilometres", whereas the article is written in American English, but I don't know how to change that since it's generated by the software.

Old Father Time (talk) 21:00, 22 November 2009 (UTC)

Oops! Forgot - there is a way to change that. J. Spencer (talk) 22:50, 22 November 2009 (UTC)

[1] Pope KO, Ocampo AC, Kinsland GL, Smith R (1996). "Surface expression of the Chicxulub crater". Geology. 24 (6): 527–30. doi:10.1130/0091-7613(1996)024<0527:SEOTCC>2.3.CO;2. PMID 11539331.{{cite journal}}: CS1 maint: multiple names: authors list (link)

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