tag:blogger.com,1999:blog-5519292617097628087.post3849089034376294018..comments2024-01-02T16:09:12.886-07:00Comments on Chinleana: Why I Use Pseudosuchia Instead of Crurotarsi for the Crocodile-line ArchosaursBill Parkerhttp://www.blogger.com/profile/05941940882532354219noreply@blogger.comBlogger24125tag:blogger.com,1999:blog-5519292617097628087.post-84449524975964977732009-11-07T10:50:27.345-07:002009-11-07T10:50:27.345-07:00Sure we can use both names and we tend to use them...Sure we can use both names and we tend to use them interchangeably. The point is that they are defined differently, and if certain specifiers within Crurotarsi are found the fall outside of Archosauria, then what is included within Crurotarsi can change radically (e.g., dinosaurs would be crurotarsans).<br /><br />I'm not familiar with Teleocrateridae which is presumably based on Teleocrater, an isolated vertebra from the Middle Triassic of Tanzania and currently a nomen nudum. Presumably this is a Family created for a group of "rauisuchids"?Bill Parkerhttps://www.blogger.com/profile/05941940882532354219noreply@blogger.comtag:blogger.com,1999:blog-5519292617097628087.post-62507478726739454232009-11-07T06:49:32.177-07:002009-11-07T06:49:32.177-07:00But there is a way we can use both Crurotarsi and ...But there is a way we can use both Crurotarsi and Pseudosuchia... :<br />Pseudosuchia is the clade containing Crurotarsi and the problematic (obscure and possiblu Nomen nudum) Teleocrateridae<br />What do you think about it?Georgios Georgalisnoreply@blogger.comtag:blogger.com,1999:blog-5519292617097628087.post-21813863493789134892009-11-04T10:54:25.609-07:002009-11-04T10:54:25.609-07:00Good points, Mickey.Good points, Mickey.Mike Keeseyhttps://www.blogger.com/profile/00147156174467903264noreply@blogger.comtag:blogger.com,1999:blog-5519292617097628087.post-86460870667229896492009-11-04T09:15:35.538-07:002009-11-04T09:15:35.538-07:00One more thought. Mike Keesey wrote- "Still,...One more thought. Mike Keesey wrote- "Still, note that Recommendation 11A might allow a definition like Clade(Aetosaurus ← [insert dinosaur here]) or something. So there's a legitimate case to be made for naming the total group "Pseudosuchia" under the PhyloCode."<br /><br />The problem I have with that is that dinosaurs were not originally paired against Pseudosuchia. Zitell named it as a taxon of Crocodilia, opposing Parasuchia, Mesosuchia and Eusuchia. If anything, his version of Crurotarsi was Crocodilia, since that included aetosaurs, paruchians, sphenosuchians, more derived crocs and later ornithosuchids. Nor is the classical Pseudosuchia of Romer paired against dinosaurs, with it being a subgroup of Thecodontia paired against aetosaurs, parasuchians and proterosuchians. As it included basal avemetatarsalians (e.g. Lagosuchus, Scleromochlus, Lagerpeton), it would be equivalent to crown Archosauria if anything.Mickey Mortimerhttps://www.blogger.com/profile/08831823442911513851noreply@blogger.comtag:blogger.com,1999:blog-5519292617097628087.post-89690756185691709192009-11-03T21:40:00.412-07:002009-11-03T21:40:00.412-07:00Phylonyms could actually use some more authors in ...<i>Phylonyms</i> could actually use some more authors in these areas, for sure. (And other areas as well -- last I heard we have NOTHING for <i>Insecta</i> at all.) If you're interested in working on this volume, it may not be too late. (Although it may be -- I'm not sure.) Contact the editors: Jacques Gauthier, Kevin de Queiroz, and Philip Cantino. And even if definitions for these names don't get in to <i>Phylonyms</i>, there's still time to prepare manuscripts for when the <i>PhyloCode</i> is enacted.<br /><br />On a related note, I'm currently a member of the Committee on Phylogenetic Nomenclature (as is Kevin Padian, previously mentioned), and we are currently considering some revisions to the code, especially to do with the term "extant". (The term "Recent" will likely be stricken from the the next draft.) If anyone has concerns, I'd be happy to bring them up.Mike Keeseyhttps://www.blogger.com/profile/00147156174467903264noreply@blogger.comtag:blogger.com,1999:blog-5519292617097628087.post-90029859435695710142009-11-03T21:24:49.168-07:002009-11-03T21:24:49.168-07:00Mike - yeah, I find it much better to have the tot...Mike - yeah, I find it much better to have the total and crown group names paired together rather than separated. And maybe its just me, but I find it less intuitive and more of a pain to sort through hundreds of "Pan-" names, when if a suffix is implemented, I only have to look through two names that start the same way.<br /><br />Bill - I agree with you about the "starting over" part. I am very much in favor of Phylocode, but I find it dissapointing that so many perfectly well-defined clade names and definitions will be thrown away. I hope in their wisdom, the authors of the chapters for the Phylonyms companion volume will try and preserve as many of these commonly used names as possible. I think that priority of definition is an important thing, and I'd hate to see all that thrown away.<br /><br />One thing that bothers me specifically about Archosauriformes is that none of the workers who are real active among basal archosaurs have been asked to co-author the chapter for Phylonyms, as far as I'm aware. Shouldn't the active users of the definitions have a say in their construction?220myahttps://www.blogger.com/profile/06403919493457640549noreply@blogger.comtag:blogger.com,1999:blog-5519292617097628087.post-49670791749798233902009-11-03T19:48:08.043-07:002009-11-03T19:48:08.043-07:00I always forget that when Phylocode is implimented...I always forget that when Phylocode is implimented we will pretty much be starting over with names. <br /><br />This has been a real interesting discussion. Thanks guys. Believe me this discussion will have relevance soon.<br /><br />BTW...for the other clade I tend to use Ornithodira because as Mickey says Ornithosuchia is out because it includes Ornithosuchus. Guess that sort of makes me a hypocrite as Ornithosuchia is the first defined name. ;)Bill Parkerhttps://www.blogger.com/profile/05941940882532354219noreply@blogger.comtag:blogger.com,1999:blog-5519292617097628087.post-31210249417612284652009-11-03T15:52:41.088-07:002009-11-03T15:52:41.088-07:00"I really don't care about the historic u..."I really don't care about the historic usage of the word Pseudosuchia, just its current meaning. It's not too hard to block out that past usage if you try."<br /><br />To me it seems improper to change the meaning of names so much that they lose all resemblence to their original usage.<br /><br />"Recommendation 11A is a good one for FUTURE use as this will help eliminate potential confusion; however, I do not see why we need to discard all of the older defined names just because this recommendation was not in place in 1984. Bringing back Crocodylotarsi doesn't help anything."<br /><br />Sure it does, since Crocodylotarsi has only ever had one concept associated with it. With Pseudosuchia, I'd have to specify sensu Gauthier and Padian, sensu Zittel, sensu Romer, etc..<br /><br />"It seems to me that there is just a general dislike among VPs for the name Pseudosuchia. Am I imagining this? Is it really that confusing?"<br /><br />I can assure you I have no personal bias against the name. I'm the one who's all for maintaining Reptilia, Megalosauroidea, and other archaic names after all (go Podokesauroidea!). I just think it was improperly defined by Gauthier and Padian, just like I won't use Sereno's (1998, 1999) definitions of Ornithomimidae, despite them being the first published.<br /><br />"I'm curious as to what people think the name of the sister total group, i.e., the avian total group, should be. Sereno discussed this and opted for "Avemetatarsalia". For the same reasons outlined above, I prefer "pan-Aves" (or "Pan-Aves" once it's published). Other options include "Ornithodira", "Ornithosuchia", "Panaves", "Aves", "Ornithotarsi", and the rather poetic "Dracones"."<br /><br />Ornithodira and Ornithotarsi are less inclusive, Ornithosuchia fails due to not including Ornithosuchus, Aves shouldn't be nearly so inclusive, Dracones has never been defined, and Panaves was defined after Avemetatarsalia. So I go with Avemetatarsalia.Mickey Mortimerhttps://www.blogger.com/profile/08831823442911513851noreply@blogger.comtag:blogger.com,1999:blog-5519292617097628087.post-48849632014001405352009-11-03T11:51:23.711-07:002009-11-03T11:51:23.711-07:00I'm curious as to what people think the name o...I'm curious as to what people think the name of the sister total group, i.e., the avian total group, should be. <a href="http://taxonsearch.org/dev/taxon_edit.php?Action=View&tax_id=39" rel="nofollow">Sereno</a> discussed this and opted for "Avemetatarsalia". For the same reasons outlined above, I prefer "pan-Aves" (or "<i>Pan-Aves</i>" once it's published). Other options include "<i>Ornithodira</i>", "<i>Ornithosuchia</i>", "<i>Panaves</i>", "<i>Aves</i>", "<i>Ornithotarsi</i>", and the rather poetic "<i>Dracones</i>".Mike Keeseyhttps://www.blogger.com/profile/00147156174467903264noreply@blogger.comtag:blogger.com,1999:blog-5519292617097628087.post-50169554369850692362009-11-03T10:43:10.937-07:002009-11-03T10:43:10.937-07:00Um, doesn't it make it easier to find names of...Um, doesn't it make it <b>easier</b> to find names of total clades? A suffix would ensure that they are scattered to the four winds. (Although they would be paired with their corresponding crown clade names, which I suppose would be nice. In either case, a standardized affix helps.)<br /><br />As for "unimaginative", utility trumps that. If I know there's a clade called "<i>Goomboppiformes</i>" and later on I see a clade called "<i>Pan-Goomboppiformes</i>", then I know exactly what it is. If I see "<i>Ploogenjoamorpha</i>" then I have no idea.<br /><br />Even if we did use a suffix, "<i>-formes</i>" would be a bad choice, since a great number of crown group names end in that suffix. We'd have stuff like <i>Passeriformes-formes</i>. (I guess "<i>-morpha</i> might be all right, though. And <a href="dx.doi.org/10.1371/journal.pone.0007062" rel="nofollow">it has been tried</a>.)<br /><br />Still, though -- "<i>Pan</i>" means "total" and "<i>morpha</i>" means "forms". If you want to establish a convention for a type of taxon, doesn't it make more sense to pick an affix that refers directly to that type of taxon? These are total groups, not form taxa.Mike Keeseyhttps://www.blogger.com/profile/00147156174467903264noreply@blogger.comtag:blogger.com,1999:blog-5519292617097628087.post-86863336265429667592009-11-03T10:22:36.119-07:002009-11-03T10:22:36.119-07:00I really hate the idea of using "Pan-" a...I really hate the idea of using "Pan-" as a prefix for all total clades. Not only is it unimaginative, but it really screws things up for stuff like databases. Imagine having to sort through a drop-down menu of clade names, and half of them start with Pan-. Or even sorting through a simple list! If you are going to standardize clade names, I would much prefer a standard suffix, like -morpha or -formes.220myahttps://www.blogger.com/profile/06403919493457640549noreply@blogger.comtag:blogger.com,1999:blog-5519292617097628087.post-2546722785265331282009-11-03T10:14:32.054-07:002009-11-03T10:14:32.054-07:00"BTW.. what happens if all modern crocodylian...<i>"BTW.. what happens if all modern crocodylians happen to go extinct?"</i><br /><br />Then we'll have other problems to worry about, since, if this happens in our lifetimes, it will probably mean that the planet's entire ecosystem is imploding. :)<br /><br />Seriously, though ... <i>PhyloCode</i> definitions that rely on the concept of "extant" require it to have an objective, unchanging meaning in the context of the definition. Either the author(s) can select one, or, if they do not, then the implicit meaning is "extant on [the definition's] publication date" (Art. 9.5). In cases where this is not clear, the definition can be clarified through an unrestricted emendation (Art. 15.11–15.15).<br /><br />In short, they'd still be crocodylians, and everything sharing closer ancestry with them than with anything else extant at the time of definition would be pan-crocodylians.Mike Keeseyhttps://www.blogger.com/profile/00147156174467903264noreply@blogger.comtag:blogger.com,1999:blog-5519292617097628087.post-38135774191590580552009-11-03T10:01:50.890-07:002009-11-03T10:01:50.890-07:00Sometimes the conversion of a paraphyletic group t...Sometimes the conversion of a paraphyletic group to a clade takes (<i>Dinosauria</i>, <i>Synapsida</i>) and sometimes it doesn't (<i>Reptilia</i>, <i>Thecodontia</i>). This is one where I think it's not that clear.<br /><br />Still, note that Recommendation 11A might allow a definition like Clade(<i>Aetosaurus</i> ← [insert dinosaur here]) or something. So there's a legitimate case to be made for naming the total group "<i>Pseudosuchia</i>" under the <i>PhyloCode</i>. If that happens, though, I'll probably prefer the informal alternative "pan-Crocodylia" because it fits in better with the general scheme of "panclade names". (Vertebrate paleontology is one of the few fields--or the only one?--where total groups have been explicitly named. Few other taxa have stem groups that are as well-known and studied.)<br /><br />I like the "<i>Pan-</i>" convention. It's clear, and to can be applied to any crown group name. There's only one place where I think it falls apart, and that's for apes. (Think about it....)Mike Keeseyhttps://www.blogger.com/profile/00147156174467903264noreply@blogger.comtag:blogger.com,1999:blog-5519292617097628087.post-79101796374995380382009-11-03T09:19:36.622-07:002009-11-03T09:19:36.622-07:00Mickey/Mike,
Recommendation 11A is a good one for...Mickey/Mike,<br /><br />Recommendation 11A is a good one for FUTURE use as this will help eliminate potential confusion; however, I do not see why we need to discard all of the older defined names just because this recommendation was not in place in 1984. Bringing back Crocodylotarsi doesn't help anything.<br /><br />It seems to me that there is just a general dislike among VPs for the name Pseudosuchia. Am I imagining this? Is it really that confusing?Bill Parkerhttps://www.blogger.com/profile/05941940882532354219noreply@blogger.comtag:blogger.com,1999:blog-5519292617097628087.post-75672824048433461752009-11-03T09:04:54.068-07:002009-11-03T09:04:54.068-07:00Nick,
The definition of Crurotarsi is based in pa...Nick,<br /><br />The definition of Crurotarsi is based in part on where phytosaurs fall out (I'm picking on them because they are currently accepted as the basal-most taxon). So say a future analysis finds Revueltosaurus outside of Phytosauria, then yes Revueltosaurus (or some future unknown taxon in the same position) would be a non-crurotarsan Pseudosuchian.<br /><br />Pan-Crocodylia....ugh... I don't know if I can do that yet, although I'll admit that its meaning would be clear. Still, it would just be a replacement name for Pseudosuchia, so what is the point except to make crown clade names uniform (BTW.. what happens if all modern crocodylians happen to go extinct?). I really don't care about the historic usage of the word Pseudosuchia, just its current meaning. It's not too hard to block out that past usage if you try.Bill Parkerhttps://www.blogger.com/profile/05941940882532354219noreply@blogger.comtag:blogger.com,1999:blog-5519292617097628087.post-50110260936276589312009-11-03T00:19:30.510-07:002009-11-03T00:19:30.510-07:00FWIW, the PhyloCode, which both Gauthier and Padia...FWIW, the <i>PhyloCode</i>, which both Gauthier and Padian are involved with, would disfavor Gauthier and Padian's definition for the very reason Mickey states. See <a href="http://www.ohio.edu/phylocode/art11.html" rel="nofollow">Recommendation 11A</a> (with <i>Dinosauria</i> as a specific example).<br /><br />I'm not sure about Padian, but Gauthier now supports the <i>Pan-</i> convention for names of total groups. Arguing for using "<i>Pseudosuchia</i>" for the total group may put you in the odd position of disagreeing with the original definitional authors! Granted, there's no good published alternative for now, but hopefully "<i>Pan-Crocodylia</i>" will be published along with the <i>PhyloCode</i> or shortly thereafter.Mike Keeseyhttps://www.blogger.com/profile/00147156174467903264noreply@blogger.comtag:blogger.com,1999:blog-5519292617097628087.post-66346006020108311572009-11-03T00:02:14.789-07:002009-11-03T00:02:14.789-07:00Interesting problem. I do support using names wit...Interesting problem. I do support using names with temporal priority and I don't care at all about etymology. My issue with Gauthier's definition is that it uses crocodiles as the internal specifier instead of Dyoplax, Aetosaurus or Typothorax (Zittel's original pseudosuchians). And yes, I have the same issue with definitions of Dinosauria, Saurischia, Theropoda, Coelurosauria, etc. that include birds. In fact, Pseudosuchia originally excluded not only mesoeucrocodylians, but also parasuchians. So I'd support Pseudosuchia for some (Aetosaurus <- Parasuchus, Crocodylus) clade, but not for pan-crocodylians. And yes, I know Dinosauria etc. didn't originally include birds, but the latter ended up being deeply nested in it whereas pseudosuchians ended up being thrown every which way compared to parasuchians and crocs.<br /><br />As for Crurotarsi, Sereno's definition is terrible, so par for the course there. I cringe at redefining clades a decade after the fact though, so I might very well support Crocodylotarsi as the lesser of three evils when it comes to pan-crocs. Or would I overcome my hatred of pan-names and embrace Pan-Crocodylia? Luckily I work on theropods so don't have to come to a conclusion any time soon. ;)<br /><br />Incidentally, I agree with Nick that the currently crappy topologies in that part of the tree leave open the possibility of non-crurotarsan pseudosuchians (sensu Gauthier and Padian).Mickey Mortimerhttps://www.blogger.com/profile/08831823442911513851noreply@blogger.comtag:blogger.com,1999:blog-5519292617097628087.post-44166208786588609832009-11-02T22:27:33.196-07:002009-11-02T22:27:33.196-07:00Well Bill, there have to be taxa between the clade...Well Bill, there have to be taxa between the clade that has the stem-based definition and the clade that has the node-based definition, we just either don't recognize them currently or we haven't found them yet.<br /><br />That's what I'm getting at.<br /><br />Best Wishes,<br />NickNickhttps://www.blogger.com/profile/08718847558790015112noreply@blogger.comtag:blogger.com,1999:blog-5519292617097628087.post-2932527018149445262009-11-02T22:24:59.844-07:002009-11-02T22:24:59.844-07:00Crurotarsi and Pseudosuchia currently have the sam...Crurotarsi and Pseudosuchia currently have the same content because all of the specifiers for Crurotarsi currently fall out after the split wih Ornithodira. If one of these specifiers falls outside of the crown clade then the content of Crurotarsi would change significantly.<br /><br />I would use the redefined Crurotarsi if another name (Pseudosuchia) did not exist. However, Pseudosuchia has priority, is stable, and is not confusing. Why should we use Crurotarsi?Bill Parkerhttps://www.blogger.com/profile/05941940882532354219noreply@blogger.comtag:blogger.com,1999:blog-5519292617097628087.post-71321064752317173862009-11-02T06:02:39.769-07:002009-11-02T06:02:39.769-07:00So effectively both names are probably not represe...So effectively both names are probably not representing the same clade, just maybe most analyses don't have good enough taxon sampling or we don't yet have taxa in between yet known...? :P<br /><br />Sorry for the double post... I hit post too quickly before I'd finished my thoughts...Nickhttps://www.blogger.com/profile/08718847558790015112noreply@blogger.comtag:blogger.com,1999:blog-5519292617097628087.post-40594016343660345662009-11-02T06:01:12.038-07:002009-11-02T06:01:12.038-07:00Actually Bill, I think the more likely situation f...Actually Bill, I think the more likely situation for Crurotarsi to be valid with that definition is that there would be taxa basal to Crurotarsi within Pseudosuchia... no?<br /><br />Cheers,<br />NickNickhttps://www.blogger.com/profile/08718847558790015112noreply@blogger.comtag:blogger.com,1999:blog-5519292617097628087.post-50546090826486458472009-11-02T01:17:01.250-07:002009-11-02T01:17:01.250-07:00Also, Sereno redefined Crurotarsi as a total group...Also, <a href="http://www.taxonsearch.org/dev/taxon_edit.php?tax_id=365&Action=View" rel="nofollow">Sereno redefined <i>Crurotarsi</i> as a total group (branch-based), claiming that was his original node-based definition was "in error"</a>. Make of that what you will.Mike Keeseyhttps://www.blogger.com/profile/00147156174467903264noreply@blogger.comtag:blogger.com,1999:blog-5519292617097628087.post-60498474324360572972009-11-02T01:13:14.161-07:002009-11-02T01:13:14.161-07:00As I noted on the VERTPALEO List, the total group ...As I noted on the VERTPALEO List, the total group may be named "<i>Pan-Crocodylia</i>" under the <i>PhyloCode</i>, anyway (as part of the general convention of naming total groups "<i>Pan-</i>[name of corresponding crown group]"). This name is not mandated, though, so one of the others could be used instead. But even if something else is chosen, "pan-Crocodylia" (unitalicized, lower-case "p") would remain useable as an informal name.<br /><br />Personally, I think this is one case where the <i>Pan-</i> convention works quite well, but I guess we will see.Mike Keeseyhttps://www.blogger.com/profile/00147156174467903264noreply@blogger.comtag:blogger.com,1999:blog-5519292617097628087.post-57125309857629574732009-11-01T21:39:44.489-07:002009-11-01T21:39:44.489-07:00I want it on a fuckin T-shirt.
As Bill circumspect...I want it on a fuckin T-shirt.<br />As Bill circumspectly alluded to, the definition differences between Pseudosuchia and Crurotarsi are about to get very important, and the latter term is about to change its understood meaning to the point of becoming completely useless.Jeffrey W. Martz, PhDhttps://www.blogger.com/profile/08923720923588241488noreply@blogger.com