Talk:Dinosauromorpha

Merger proposal: Dinosauriformes

According to recently published papers[1][2], lagerpetids may belong to Pterosauromorpha. Dinosauriformes are less inclusive than Dinosauromorpha by definition, but in the new topology, all dinosauriformes are dinosauromorphs. HFoxii (talk) 06:06, 2 October 2021 (UTC)

Support. Arguably, Dracohors should be merged too, since nearly all dinosauriforms are members of that clade —Trilletrollet [ Talk | Contribs ] 18:16, 6 October 2021 (UTC)

It makes sense. Dracohors differs from Dinosauria only in that it possibly includes silesaurids (which, according to another version, are ornithischian dinosaurs). HFoxii (talk) 03:45, 7 October 2021 (UTC)

• But should we really act on the basis of a single, recent study? FunkMonk (talk) 02:57, 7 October 2021 (UTC)
  • @FunkMonk: There are already at least two studies. In any case, Dinosauromorpha despairs of Dinosauriformes only by possibly including one small family of controversial phylogenetic position. HFoxii (talk) 03:45, 7 October 2021 (UTC)

I agree with FunkMonk that there is no need to rush and merge the pages based on two papers (which share some authors). Otherwise we should be merging Silesauridae and Ornithischia, separating Herrerasauria from Herrerasauridae and so on. Let's wait to see how the forthcoming papers will deal with this issue. Usually it takes about 2 to 3 years for a new hypothesis/proposal to be actually tested by paleontologists.--Maurissauro (talk) 03:58, 7 October 2021 (UTC)

@Maurissauro: I am not saying that all new proposed taxonomic changes should be accepted immediately. However, isn't in this case it is more convenient to cover all points of view in one article? HFoxii (talk) 05:24, 7 October 2021 (UTC)

We have a lot more articles about insignificant, tiny clades of much less note that would be more urgent to merge then. Seems weird to start merging large clades, when articles for small, little known clades pop up all the time. FunkMonk (talk) 09:24, 27 January 2022 (UTC)

• Question - does this mean that some people consider Dinosauromorpha to be monotypic? If not, then I see no reason to merge. --awkwafaba (📥) 13:10, 27 January 2022 (UTC)
  • Yes, if lagerpetids are classified as pterosauromorphs, then Dinosauromorpha includes only Dinosauriformes. HFoxii (talk) 16:49, 27 January 2022 (UTC)

If that's the only difference, then I'd think both clades could be covered in the same article regardless of what system we follow. FunkMonk (talk) 17:05, 27 January 2022 (UTC)

Support not only a merge of Dinosauriformes, but also Dracohors. Basal classification is such a mess I dont think its worth having these as separate articles. If lagerpetids are pterosauromorphs, Dinosauriformes = Dinosauromorpha. If silesaurids are ornithischians, Dracohors = Dinosauria. It's a complex situation and none of the articles are long enough to really be worth having separate especially given the volatility of the situation. IJReid ^{{{T - C - D - R}}} 19:08, 27 January 2022 (UTC)

Support IJReid's proposal on the basis of concision and comprehensibility. Lythronaxargestes (talk | contribs) 19:13, 27 January 2022 (UTC)

Also agrees with the proposal to merge Dinosauriformes and Dracohors into Dinosauromorpha. HFoxii (talk) 04:40, 28 January 2022 (UTC)

Support - after IJReid's simpler explanation. FunkMonk (talk) 14:14, 31 January 2022 (UTC)

Support IJReid's proposal. Covering all three in one article would be the most comprehensive and easy way to explain it all, rather than strewing the information across three different articles. --SilverTiger12 (talk) 17:59, 31 January 2022 (UTC)

Given the unanimous support for the merge (and no oppositions to a merge of Dracohors as well), I've gone ahead and improved the article, including all relevant content, and redirected both pages here.

Position of Agnosphitys and Pisanosaurus

@IJReid: I was wondering which papers suggest that Agnosphitys and Pisanosaurus are outside the Silesauridae + Dinosauria clade (aka Dracohors). I have tried to move them into Dracohors based on my understanding of the consensus, but this has been reverted twice. I've started this discussion as a space to go into this in more detail. Fanboyphilosopher (talk) 23:35, 31 January 2022 (UTC)

I was going to continue this in the above discussion, but here works. Agnolin 2015 only states that Pisanosaurus is within Dinosauriformes. Fraser ea 2002 has Agnosphitys in Dinosauriformes with no reference to Marasuchus. Without the reference to Marasuchus, to assume either falls within Dracohors is simply OR. And even with the inclusion of reference to Marasuchus, Cau 2018 never discusses Agnosphitys, and places Pisanosaurus within Silesauridae. If Agnolin 2015 is ignored, Pisanosaurus shouldn't be listed on this page at all, it would be discussed only in Ornithischia and Silesauridae. And no papers other than Cau 2018 use or define Dracohors, so assuming that its placement in Dinosauriformes in all previous studies would place it in Dracohors is OR. Even labelling Dracohors in the cladogram of Ezcurra ea 2020 could be considered OR, because they never acknowledge the name is used, and it is creating a synthetic diagram that has never been published. The only papers other than Cau 2018 which we could reference for the contents of Dracohors are Baron 2020 (silesauridae, herrerasaurus, dinosauria), Kammerer ea 2020 (silesauridae, dinosauria), and Novas ea 2021 (silesauridae (may be ornithischian), herrerasauria, dinosauria). No previous phylogenetic analyses are mentioned (except Nesbitt ea 2010) so we can't really retroactively place the clade on any other trees, unlike the situation with all the names defined by Madzia ea 2021. To say, without reference, that Agnosphitys, Nyassasaurus, or Pisanosaurus, when they are outside Dinosauria or Silesauridae, are Dracohors, is OR. IJReid ^{{{T - C - D - R}}} 00:37, 1 February 2022 (UTC)

When you mention Agnolin 2015, are you referring to the conference abstract? Because the phrasing used by that source was "Pisanosaurus como un Dinosauriformes basal, por fuera de Dinosauria, y conjuntamente con Silesauridae" (Pisanosaurus as a basal dinosauriformes, outside Dinosauria, and jointly with Silesauridae). That seems to be pretty conclusively placing it in the Silesauridae + Dinosauria clade, and the 2017 paper published off the research in question presents that conclusion. I should reiterate that Dracohors is not a new or novel hypothesis, a Silesauridae + Dinosauria clade has been found pretty consistently since 2003. Cau simply provided a name to the clade, and it is misleading to argue that a reference by his paper is a prerequisite for placing genera within the clade. Pisanosaurus is never found to be more basal than Silesauridae, therefore it should not be presented as such in the taxobox. That would be original research, how I see it. Pisanosaurus is either a silesaurid or a dinosaur (or both), and placing it in Dracohors, by itself, shows that we are placing it among its plausible relatives but not concluding which one it lies in. This is pretty standard procedure in paleontology taxoboxes: if you can't decide between two phylogenetic options, then place the taxon in question at the fork. Same reason why there's such a long list of uncertain taxa (Herrerasauria, Chilesaurus, etc.) in the taxobox of Dinosauria, or why Faxinalipterus is at the base of Ornithodira, or so many other examples. If you wish to change that tradition, then you have a lot of work and disagreement ahead of you.

As for your other points, I agree that Dracohors should not be retroactively added to cladograms published before 2018, at least not without a small text disclaimer below the cladogram. As for Nyasasaurus, I never said it was in Dracohors. As for Agnosphitys, I don't think it's fair to be concluding that it was basal to Dracohors considering that the 2002 paper came out before Silesaurus. And even then, the 2002 paper places it crownward of Marasuchus and Herrerasaurus, so there is far from "no reference to Marasuchus". Everything published since then has established that Agnosphitys is in the Silesauridae + Dinosauria clade (aka Dracohors), unless I'm missing a source. If you insist that there's a chance it's stemward of silesaurids, then what's the problem with placing it in Dracohors and adding a little (?) next to the name. And one last point: why are you putting (?) next to taxa which are consistently considered to be dinosauriforms, like Marasuchus. It's a dinosauriform by definition, no doubt required. Yes, its validity relative to Lagosuchus is uncertain, but wouldn't something like (junior synonym?) be less misleading than a simple (?)? Same with Saltopus being an unambiguous dinosauriform (iirc), though if you have a source placing it outside Dinosauriformes, then I'll retract that statement. And Silesauridae is also within Dracohors by definition, so it has even less of an excuse to have a (?). Fanboyphilosopher (talk) 01:54, 1 February 2022 (UTC)

I should add that I realize now that Dracohors is branch-based (crownward of Marasuchus) rather than node-based. So Pisanosaurus and Agnosphitys are definitely dracohorsian in every source I'm aware of, and my overall point still stands. Fanboyphilosopher (talk) 01:57, 1 February 2022 (UTC)

What you're suggesting, combining the results of studies that find dracohorsian Pisanosaurus, Agnosphitys, and Nyasasaurus (closer to Dinosauria than Silesauridae in all Nesbitt ea 2013 results), with the definition provided by Cau 2018, is WP:SYNTH, and thus Original Research. Without explicit mention, we cannot conclude that any of the three taxa, which phylogenetically are clearly within the clade, are members of Dracohors and not Dinosauriformes. The infobox should follow the text of the article, where Pisanosaurus is dinosauriform or silesaur or ornithischian, Nyasasaurus is dinosauriform or theropod or ornithischian or sauropodomorph, Agnosphitys is dinosauriform or silesaurid or saurischian, and Saltopus is dinosauriform or saurischian. The only taxon you could get away with moving without it being pure WP:SYNTH is Pisanosaurus, since it was a silesaurid in Cau 2018, but that source would have the taxon removed entirely from the infobox. As I said, even labelling Dracohors on the Ezcurra cladogram, where it clearly could go, is WP:SYNTH, but I overlook it for the sake of clarity. IJReid ^{{{T - C - D - R}}} 03:08, 1 February 2022 (UTC)

I don't understand what you're saying. Pisanosaurus and Agnosphitys have never been found stemward of Marasuchus (if you have a source objecting to this statement, please present it), and therefore they are part of the branch-based clade including all dinosauriforms crownward of Marasuchus. Cau 2018 named that clade Dracohors. Therefore, no one has ever argued that those taxa are outside of the clade which is named Dracohors. That's not original research, I'm representing the consensus. Placing them outside of the clade is going against consensus. I think you're getting too caught up on the name, the name is just a label for a well-established relationship which we should present in the taxobox one way or another. You do not need a source to explicitly state "Agnosphitys is within Dracohors", because its phylogenetic position makes that clear. Same reason you do not need a source to state that snakes are tetrapods, or whales are mammals, or anything else made clear by their phylogenetic position. And once again, I'm not talking about Nyasasaurus. I'm not arguing that it should be within Dracohors. I'm also not talking about editing the cladograms. This is entirely about the taxobox, which should present the consensus on these animals (which genera are in which clades, or whether the membership of a genus in a clade is uncertain). Pisanosaurus and Agnosphytis might be silesaurids or they might be dinosaurs. But one thing is for certain: they are crownward of Marasuchus, and thus dracohorsians (by definiton of the clade Dracohors). That's not my conclusion, that's the conclusion of every paper discussing them in the past two decades. Fanboyphilosopher (talk) 03:27, 1 February 2022 (UTC)

"Agnosphitys and Pisanosaurus are consistently found to be in a clade containing all dinosauriforms crownward of Marasuchus." is a true statement. "The clade containing all dinosauriforms crownward of Marasuchus was named Dracohors by Cau, 2018." is also a true statement. Is it really WP:SYNTH to say that "Agnosphitys and Pisanosaurus are in the clade Dracohors"? I think no, you think yes. To give another example, "Dendrocygna guttata is a member of the clade Dinosauria" would not be an example of WP:SYNTH, even if there is not a source which explicitly says that exact phrase or presents it in a cladogram. Admittedly saying that it's a dinosaur would not be relevant on its page, but I'm just referencing the principle at stake here. Fanboyphilosopher (talk) 03:38, 1 February 2022 (UTC)

The definition of WP:SYNTH, a subsection of the Original Research policies, is that we aren't to combine material from multiple sources to reach a conclusion not explicitly stated by any source. The definition of Dracohors (Cau 2018) and the placements of Pisanosaurus, Agnosphitys, Nyasasaurus, and Saltopus (Agnolin 2015, Fraser 2002, Nesbitt 2013, Baron 2017) are different sources, and we are not supposed to combine the material from them to conclude any of those taxa are members of Dracohors. We *do* need explicit referrals of them to the clade, or explicit statements of the clade Dracohors being applied to *any* of the analyses that find them as stem dinosauriformes, in order to be able to say they are members of Dracohors. Thats what WP:SYNTH requires; anything else is OR. So yes, it is synth to say "Agnosphitys and Pisanosaurus are members of Dracohors". Easily-verifiable facts, like a duck being a member of Aves, means that references of Aves to Dinosauria apply. It is not easily-verifiable to say any of the taxa in question here are members of Dinosauria, and even if it were, they need to be non-silesaurid, non-dinosaurian members of Dracohors to be listed in the infobox. IJReid ^{{{T - C - D - R}}} 03:39, 1 February 2022 (UTC)

We're obviously running around in circles here. To me, placing Agnosphitys and Pisanosaurus outside of Dracohors is equivalent to presenting the idea that they are stemward of Marasuchus, which is going against consensus. So you're accusing me of OR and I'm accusing you of OR, even though we're talking about the exact same data and phylogenetic hypotheses. I would like us to bring in some neutral parties (FunkMonk, Lythronaxargestes, etc.) in order to get a second opinion. Fanboyphilosopher (talk) 03:49, 1 February 2022 (UTC)

I would say that placing any of them within Dracohors in the taxobox would require a citation, since the text only ever mentions them as dinosauriforms, and there is no reference for content in the infobox section. I'm willing to allow someone else to put in their two cents. IJReid ^{{{T - C - D - R}}} 04:00, 1 February 2022 (UTC)

I must say I don't know enough about this part of the tree to make a qualified judgment. But as I understand, are we talking about placing some taxa in named clades that they have not been placed in in the literature? They have been placed in the clades before they were named? Is there a way to show these clades without using the names? FunkMonk (talk) 11:02, 1 February 2022 (UTC)

The situation is your second statement: Agnosphitys and Pisanosaurus are reliably found to be bird-line archosaurs crownward of Marasuchus, though there is debate over whether they are silesaurids or dinosaurs. In 2018, Cau gave the name "Dracohors" to the branch-based clade crownwards of Marasuchus. So yes, they have been unanimously (iirc) placed into that clade before the clade was named. As far as I'm aware, there isn't a way to present a clade without using its name, and this is not usually a problem. This is the first time I have ever heard of anyone arguing that it's WP:SYNTH, since there aren't any sources which explicitly say "Agnosphitys is in Dracohors", even though that is the consensus position. Fanboyphilosopher (talk) 15:26, 1 February 2022 (UTC)

Hmmm, I guess that would make both versions "synth" in light of Wikipolicies. I wonder if the only compromise would be to simply not mention Dracohors in the taxobox until those taxa are explicitly included in it in a paper? In any case, I believe this cladogram would be clear synth: "Ezcurra et al. (2020, Dracohors added as defined by Cau)". If Dracohors is not used in that paper, it should not be named in the cladogram. FunkMonk (talk) 15:44, 1 February 2022 (UTC)

Agreed, about the cladogram. Fanboyphilosopher (talk) 16:04, 1 February 2022 (UTC)

The article still needs a lot of work, but I've removed Dracohors from contentious areas. One problem I see with removing it from the taxobox is that it's hard to show the relative positions of subgroups. For example, Agnosphitys is always crownward of Lagosuchus, but you'd need to break alphabetical order with no justification to make it appear like that in the taxobox. I still strongly believe we should include Dracohors in the taxobox, even if my edit says otherwise. Fanboyphilosopher (talk) 16:20, 1 February 2022 (UTC)

It certainly is tricky, and I don't have strong opinions on what to do, so maybe more editors will hopefully come along and comment. FunkMonk (talk) 16:38, 1 February 2022 (UTC)

Given that taxoboxes aren't meant to show relationships of genera beyond how they relate to the larger clade, I dont see an issue with Dracohors being include (for silesaurs, herrerasaurs, and dinosaues per Cau and later authors), and the intermediate genera excluded, implying a polytomy more than a more basal position. But if its more agreeable to simply exclude it rather than not place taxa within it, that works as well. IJReid ^{{{T - C - D - R}}} 22:15, 1 February 2022 (UTC)