Talk:Dinosaur

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If dinosaurs are reptiles

And birds are dinosaurs, then wouldn't that mean birds must be reptiles? 209.86.226.25 (talk) 01:31, 14 October 2010 (UTC)

Correct, in the cladistic system (but not the Linnaean system used in the info boxes), birds are reptiles. MMartyniuk (talk) 01:41, 14 October 2010 (UTC)

dinosaurs are not extinct, they have been spotted in numerous backyards, jungles and forestrial and industrial parks —Preceding unsigned comment added by 142.162.35.112 (talk) 12:44, 11 November 2010 (UTC)

Birds are dinosaurs, but the African cryptids are likely to be a myth. Crimsonraptor (talk) 18:50, 12 December 2010 (UTC)

Birds are not reptiles. When you say "are" you imply their current status. Birds, as the contemporary theory goes, descended from reptillian ancestors. Just as man descended from the earliest forms of mammalian life. That does not mean our current status is small mammalian rodents. Birds have reptillian ancestry, they are not currently reptiles. 204.65.34.169 (talk) 14:08, 13 January 2011 (UTC)

You are wrong, birds are reptiles. Abyssal (talk) 16:20, 13 January 2011 (UTC)

From Biology, 8th Edition by Campbell and Reece (and many other junior authors): "The reptile clade includes tuataras, lizards, snakes, turtles, crocodilians and birds, along with a number of extinct groups, such as plesiosaurs and ichthyosaurs." This is the text used in the BIO 111 course I teach. It is representative of many new texts in that birds are no longer afforded separate treatment as they were under non-cladistic classifications. --Khajidha (talk) 00:38, 17 January 2011 (UTC)

I totally agree that the two are one, it's just that it's a lot easier to treat them seperately!...But I try to include them. The classification system's so messed up that I try to make it simpler...Crimsonraptor | (Contact me) Dumpster dive if you must 00:42, 17 January 2011 (UTC)

'Birds' and 'reptiles' are just terms we have invented.Western science has long had a mania for attaching labels to living things and putting them in their proper boxes. The truth is, life varies along a broad and colourful spectrum. When can we say a reptile becomes a bird, or vice versa, unless we create artificial criteria for separating them? Science at last acknowledges this. It may be that the terms Reptilia, Aves, Mammalia, etc, will become popular terms and have no scientific value whatsoever. A bit of a nominalist perspective here.Gazzster (talk) 10:56, 17 January 2011 (UTC)

Yeah. We've completely messed up the measuring system by introducing our own "better" thing (I'm trying hard to convert back to metric). Now the classification system has fallen too. Might need a redesign someday...Crimsonraptor | (Contact me) Dumpster dive if you must 13:26, 17 January 2011 (UTC)

Under that logic Humans would be Fish, and we'd all be bacteria (or whatever the equivilent term is) --Kurtle (talk) 15:42, 4 April 2011 (UTC)

Etymology

Prior to 1842 the English word "dragon" used instead of dinosaur. (This statement should be in the Etymology section.) —Preceding unsigned comment added by 97.65.82.66 (talk) 16:13, 8 March 2011 (UTC)

Got a source? Bob the WikipediaN ^{(talk • contribs)} 19:28, 8 March 2011 (UTC)

They didn't have dinosaurs until the group was named. Between 1820 and 1842 known dinosaurs were either called by whatever genus they'd been named (Megalosaurus, Iguanodon, etc.), or under the general term "saurians". (and yes, I know what you're *really* getting at, but I'm not going to comment on that). J. Spencer (talk) 01:07, 9 March 2011 (UTC)

Distribution Maps

There's one thing missing from many, or maybe all the Dinosaur pages: Distribution Maps. DMs are VERY helpful at giving a lot of information at a glance and I think we should begin incorporating them. The Natural History Museum may be a good place to start. --Kurtle (talk) 15:45, 4 April 2011 (UTC)

I can think of a few obstacles here. One, we'd need some good, CC licensed world map type images for a large number of different time periods. Second, most dinosaurs would only be represented by a single point, or series of points. Any filling in of a broader "range" could be OR. Also, many (most) species will lack specific enough location data. MMartyniuk (talk) 16:14, 4 April 2011 (UTC)

The Paleobiology Database has countless maps that are generated by its large database. Putting together present-day range maps from these is doable, though the extensions of ranges would need to be estimated. As far as prehistoric maps go, however, we don't have very many to work with.

• Present-day map: Useful for paleontology.
• Prehistoric map: Useful for paleobiology.

Both have their benefits. Present-day maps would be easiest to generate and I wouldn't mind working on these on a per-request basis. If someone can provide me with the prehistoric map relevant to the species (and this changes drastically and quickly within a couple million years), I can build those as well. But like I said, I'm not "jumping" to work on them; I'll do them by request provided the world map exists for the requested time period and the data exists for the specimen. You can see examples of my maps at brown recluse spider and desert recluse. Bob the WikipediaN ^{(talk • contribs)} 17:56, 4 April 2011 (UTC)

Modern Definition

I looked up the reference for this sentence: "Under phylogenetic taxonomy, dinosaurs are usually defined as the group consisting of "Triceratops, Neornithes [modern birds], their most recent common ancestor, and all descendants."[12] " And while it's a faithful quote (except for the "usually" part), I'm struck by the fact that it seems extremely out of context and, well, just odd. No explanation is given in the reference for why this is the definition, or why Triceratops is the base dinosaur upon which to base all others and the definition. Neither is there any explanation for this in the article. I don't exactly know how to improve it, but I do know that it shouldn't be like this. Hires an editor (talk) 00:05, 8 April 2011 (UTC)

I think ceratopsians and birds are generally considered the most "advanced" groups in each major dinosaurian lineage, which is why they're often used. But I agree that Iguanodon/Megalosaurus is better. It reflects the original usage (required by PhyloCode) and doesn't force birds to be dinosaurs by definition, only by discovery. MMartyniuk (talk) 12:47, 8 April 2011 (UTC)

You mean "advanced" just by time, not some other characteristic? I hope. OrangeMarlin ^{Talk• Contributions} 17:44, 8 April 2011 (UTC)

Most derived, with gross body form being different from the basal state. And yeah, I'm sure time plays a role as well, as both groups diversified in the LK. MMartyniuk (talk) 17:47, 8 April 2011 (UTC)

Personally, I'd use the definition "Iguanodon, Megalosaurus and the descendants of their most recent common ancestor." It's the same set of animals, been used by professionals, and makes more intuitive sense since Megalosaurus and Iguanodon were the first dinosaurs formally named. I think the ugly Triceratops one is more commonly used for whatever reason. The set of animals is still the same, but Megalosaurus and Iguanodon are much less arbitrary anchors. Abyssal (talk) 00:35, 8 April 2011 (UTC)

Ornithischians and birds have their earliest common ancestor in the Triassic period. Of the ornithischians, the ceratopsians and ankylosaurs reverted back to fully dedicated quadrupedal posture and developed armor. That much makes sense to me, anyway. For me, Triceratops or Ankylosaurus would both serve purposefully at the reptilian end of the spectrum (has anyone got evidence of what sets Triceratops further than Ankylosaurus?). And typically, the definition I hear is more specific, citing the pigeon as the avian end of the spectrum. Bob the WikipediaN ^{(talk • contribs)} 08:07, 8 April 2011 (UTC)

Really? I always saw Passer domesticus listed as the bird anchor. Abyssal (talk) 14:11, 8 April 2011 (UTC)

My source was informal conversation; I imagine the house sparrow is more accurate, though I find that an interesting spectrum end; it seems so ordinary. Bob the WikipediaN ^{(talk • contribs)} 15:28, 8 April 2011 (UTC)

Edit: You've got me curious...I'm doing reserach now Bob the WikipediaN ^{(talk • contribs)} 15:29, 8 April 2011 (UTC)

Looks like Sibley and Alquist went for the albatross (another anchor I recall hearing before), Johansson went for the tyrant flycatcher, and Pereira, Baker, Mayr, Clarke, Cracraft, Slack, Delsuc, McLenachan, Arnason, Penny, and Butler all went for the sparrow. Sounds nearly unanimous to me, and I'd say my friends were mistaken. Bob the WikipediaN ^{(talk • contribs)} 15:50, 8 April 2011 (UTC)

OK. Not that it matters, since I still think we should go with Megalosaurus + Iguanodon. Abyssal (talk) 17:33, 8 April 2011 (UTC)

What do you mean by "go with Megalosaurus + Iguanodon"? We're here to report what reliable sources say, not choose our personal preferences. mgiganteus1 (talk) 18:10, 8 April 2011 (UTC)

I've seen that formulation used by reliable sources. Abyssal (talk) 19:26, 8 April 2011 (UTC)

If I'm not mistaken, both would point to MRCA of Ornithischia and Saurischia. Therefore, it doesn't really matter whether we use Triceratops + Passer or Megalosaurus + Iguanodon or even Eocursor + Eoparsor. Does it? Bob the WikipediaN ^{(talk • contribs)} 20:14, 9 April 2011 (UTC)

In fact since both formulations denote the same group under all current phylogenies, there's really no reason not to note that both are in wide current use (at least until PC makes one somewhat more "official"). MMartyniuk (talk) 13:06, 10 April 2011 (UTC)

Exactly. If more than one definition is used in reliable sources then let's note that fact. We don't have to choose between them. mgiganteus1 (talk) 15:17, 10 April 2011 (UTC)

None of this answers the question of why Triceratops (or other creature, per the above discussion) is the "default" definitional dinosaur. Hires an editor (talk) 19:49, 14 April 2011 (UTC)

It's an arbitrary ornithischian that's regarded as a "safe" anchor. No one's going to suddenly declare Triceratops an invalid name. Bob the WikipediaN ^{(talk • contribs)} 23:58, 14 April 2011 (UTC)

Ok, so what about the seeming "out of context" part of the sentence. There should still be some explanation of that, so it doesn't seem so odd. The way it reads right now makes it look like vandalism. Hires an editor (talk) 23:51, 15 April 2011 (UTC)

Indeed. Perhaps we can squeeze a source out of them. I'll go ask them. Bob the WikipediaN ^{(talk • contribs)} 01:03, 16 April 2011 (UTC)

I don't have a reference that triceratops in particular is used. But I reverted "arbitrary" because on its own this word implies that any dinosaur could be used. If the issue is a lack of citation, then add a cn template to the sentence, rather than the word arbitrary. de Bivort 18:59, 16 April 2011 (UTC)

Actually, that was in the middle of a quote, so an addition of the word "arbitrarily" wasn't quite appropriate there. The paragraph seems to have a sentence now that clarifies that both definitions presented include the same group, anyway. Bob the WikipediaN ^{(talk • contribs)} 21:12, 16 April 2011 (UTC)

Hah, I hadn't even seen that it was in a quote - how about that. Well, that constrains it! de Bivort 22:08, 16 April 2011 (UTC)

Ok, so I'm reading the modern definition, and I'm not expecting to see "Triceratops..." etc as the definition. I did I quick Google search, and see that the definition here leaves something to be desired. In addition, I looked at the source cited for the definition, and it doesn't offer an explanation, either. It doesn't matter what the reference is or the accuracy of the quote, but some explanation is needed to say why this is the reference point. Hires an editor (talk) 22:45, 16 April 2011 (UTC)

Sereno has this to say on the selection of anchors:

In formulation of definitions, recommendations regarding specifiers have favored (1) nested rather than basal specifiers; (2) multiple internal or external specifiers to combat uncertain relationships; (3) specifiers that are well known or readily available; (4) specifiers that accommodate alternative phylogenetic arrangements; and (5) specifiers that were originally included in traditional paraphyletic groups rather than more deeply nested members now included on the basis of monophyly (e.g., the theropod Megalosaurus bucklandi rather than the bird Passer domesticus as an internal specifier for Dinosauria)......Anchoring well-supported, widely recognized, and/or traditional dichotomies with [node-stem triplets] helps to sustain the narrative function of taxonomy.

Going on these excerpts from his work, it seems apparent that Triceratops horridus was selected for its unquestionable status as a well-known, unchallenged Ornithischian and a non-dubious taxon. Megalosaurus would have been ideal, since it has always been recognized as a dinosaur from the get-go of things, but using a well-known bird such as Passer domesticus forces anyone accepting that definition to include birds in their definition. This isn't really necessary to use P. domesticus, but it can't hurt to remind folks that birds are dinosaurs, and what better place to do so than in a definition of Dinosauria?

Sereno goes on to throw us a curveball:

...a few taxonomists have considered Sauropodomorpha (normally within Saurischia) to be more closely related to Ornithischia. Should this prove to be the case, sauropodomorphs would be relegated to Ornithischia using the aforementioned definition. This could be prevented by including a derived sauropodomorph (e.g., Saltasaurus loricatus) as an additional external specifier: Ornithischia = (>Triceratops horridus but not Passer domesticus or Saltasaurus loricatus). Given this definition, the equivalence statement "Dinosauria = Ornithischia + Saurischia" will not hold when sauropodomorphs are more closely related to ornithischians. In that case, Dinosauria = Ornithischia + Sauropodomorpha + Theropoda.

In other words, a more sauropod-friendly definition would recognize that the placement of Sauropodomorpha is unstable, redefining Dinosauria as "Triceratops, Passer, Saltasaurus, their most recent common ancestor, and all descendents".

Source: Sereno, P. (2005). "The logical basis of phylogenetic taxonomy". Systematic Biology. 54 (4): 595-619.

Bob the WikipediaN ^{(talk • contribs)} 03:42, 17 April 2011 (UTC)

Modern Definition - Wording

Thank you for doing this! I probably could have got there, but didn't really know the research well enough to look it up in a short period. Anyway, so my thought is to summarize what the source material says. Before the first sentence, we might put some discussion that says, "To get to the definition of dinosaur, we have to take an example that we all agree is a dinosaur that is from the saurosopids and neornithes groups, and their most common ancestor..." - something like that, but much better put together. I also find that another definition is hinted at in the article (and among the searches I did) - dinosaurs aren't archosaurs, because dinosaurs really start at the beginning of the Triassic... Hires an editor (talk) 12:42, 17 April 2011 (UTC)

Your statement about dinosaurs not being archosaurs is untrue; the first dinosaur in the fossil record appeared approximately midway through the Triassic. Also-- not the sauropsids, but the animals classically recognized as dinosaurs since their discovery. It's shaky wording, but really, Dinosauria is strongly based upon that (it happens that very few creatures, such as Dimetrodon and the pterodactyls, had to be ruled out of Dinosauria when the phylogenetic definition was finally established). Since Sereno 2005 has a very sound definition, I'm adding his definition to the article. Bob the WikipediaN ^{(talk • contribs)} 21:14, 17 April 2011 (UTC)

Locomotion

this page is wong some dinsaur flow and some wham and aome walkked —Preceding unsigned comment added by 88.104.171.96 (talk) 18:36, 23 April 2011 (UTC)

Where do you see the incorrect claim in the article? Offhand, ducks come to mind as exhibiting all three modes you just mentioned. Bob the WikipediaN ^{(talk • contribs)} 19:34, 23 April 2011 (UTC)

Realness

Dinosaurs only lived in missouri under water in caves. —Preceding unsigned comment added by Dinosaursarereal (talk • contribs) 01:56, 3 May 2011 (UTC)

That is a great comment, I will put it up immediatly! Bob the WikipediaN ^{(talk • contribs)} 02:00, 3 May 2011 (UTC)

Look my teacher said that wiki is unrelialbesource and that someone could say "dinosaurs only lived in missori under water in caves", can you put this up for like a day -please lol, shes a good source —Preceding unsigned comment added by Dinosaursarereal (talk • contribs) 02:06, 3 May 2011 (UTC)