We all know Martyniuk published his field guide of Mesozoic oviraptorosaurs and paravians last month. How does it hold up? I was happily surprised to see I was listed (second!) in the acknowledgements and that my Theropod Database is referenced and extensively consulted (though as the website address will change soon, that was unfortunate timing). I'll try not to let that affect the amount of scathe expected in one of my reviews. ;)
When I was little, I would read field guides instead of story books, and loved the Peterson guides due to their completeness and illustrations. More than once I started drawing my own, but I don't think I ever got past the grebes (second only to loons in all American field guides, which I now know goes back to Gaddow [1893] and Wetmore and Miller [1926]). Similarly, I loved Sattler's (1983) "The Illustrated Dinosaur Dictionary", which while not quite in field guide format, did have detailed sequential entries for every dinosaur genus and illustrations of most. So this book is appealing on a nostalgic level, despite [mostly] not being something I would return to for new technical details. It's also hot on the heels of Paul's "The Princeton Field Guide to Dinosaurs", which I reviewed and will ellicit comparison.
If any word describes this book, it's 'progressive'. Ideas are all completely up to date (e.g. the ornithomimid feather paper is used) and the phylogeny is quite good (I don't agree with it all, but it's all well referenced), but it's more than that. Clades are italicized as if Phylocode were standard already. Unpublished references are used, and many details which are probably correct but not in the literature yet are used without comment. Combined with the field guide format, it really does seems like a book written from some enlightened future where we know much more than now.
As a field guide, this is very good. The restorations are beautiful and extremely believable. These are some of the only dinosaur illustrations I've seen that seem like real animals. The coloration and plumage differences between taxa are all just what I'd expect based on recent birds. If I didn't know better, I'd figure a time machine were involved. More importantly, the details given to distinguish each species are numerous and accurate. They almost always reflect what could actually be seen in life. The habits are almost always stated with the proper amount of uncertainty, and usually explicitly supported by some anatomical detail. I found these very interesting, as I normally don't think much about the functional reason for differences between taxa. The use of common names for each species also adds to the illusion these are living creatures and not just objects of scientific study, though as expected of a field guide, scientific names are also provided along with habitat and distribution (both temporal and geographic).
I do have a few issues with it as a field guide. As in Peterson's guides, arrows point to some distinctive features in the illustrations. But in Peterson's, these features are italicized in the text and the arrows can overlap the illustration to point out a particular point, so you know exactly what to look for and where it is. Martyniuk doesn't distinguish arrowed features in the text, and the arrows end a ways from the illustration. This results in the arrows being almost useless ("so its wing... or maybe chest... is distinctive in some way... hmmm"). Also, sometimes (at least 21 times to be exact) internal anatomy is mentioned as distinctive, but while the details are correct, they aren't things any paleo bird watcher would be able to see ("Is this an Elmisaurus or a Chirostenotes? Time to shoot it and break out the hack saw to check the metatarsal III cross section"). So this takes one out of the feeling this is a field guide instead of an encyclopedia/dictionary. Another problem is that when more than one individual is shown, it's not immediately obvious what each is representing. The text usually clears it up, but Peterson's guides contain handy sex symbols, "imm.", "juv.", "adult", etc. so that you immediately know what's shown. The situation is uncommon in Martyniuk's guide since this kind of variation is known in so few Mesozoic maniraptorans, but it's still an issue. Finally, it's not always stated when species are based on young individuals (e.g. Microvenator, Eoconfuciusornis), which at least affects size and often other characters.
Scientifically, the book is highly accurate and is probably the best general text on bird origins that exists. Paul's DoA is more detailed, but also older, more heterodox and a bit daunting to the casual reader. One way in which Martyniuk's book is heterodox is its use of certain older yet not currently used clade names. Some are correct according to ICZN rules (Deinodontoidea, Ornithodesmidae, possibly Itemirinae), and these I fully support either using or petitioning the ICZN to officially suppress them. I should note though, that the ICZN also says if a family contains subfamilies, one has to be eponymous. Martyniuk doesn't use an Ornithodesminae (and indeed it would be difficult given the uncertain position of Ornithodesmus within Eudromaeosauria), but why stick to one inconvenient rule if you don't follow another? Other names (Ornithosuchia for avemetatarsalians, Segnosauria, Caenagnathiformes, Saurornithes, Odontoclae) aren't covered by the ICZN, and while I like Martyniuk's sentiment in wanting older names to retain priority, I think these are a lost cause. If we're going back to 1800's names, we should be calling Theropoda Goniopoda. I'm not for an Ornithosuchia which does not contain Ornithosuchus, so would reject that name. I do regret Segnosauria's loss to Therizinosauria. But Clarke (2004) brought Ichthyornithes back for Ichthyornithiformes, so maybe there's some hope? Other names used are not standard, like Metatheropoda, Aviremigia and Chuniaoae. Ditto for his new combination Saurornitholestes explanatus, which is based on and credited to me. Yet as I state on the Database, while I do think Laelaps explanatus is probably synonymous with Saurornitholestes langstoni, I don't formally synonymize them "because from the limited description, explanatus is indistinguishable from not only Saurornitholestes, but Bambiraptor and Velociraptor as well. It is only referred to Saurornitholestes due to provenance." I like being credited for the idea, it just hasn't been shown to be correct yet. Overall, these heterodox names are just an odd thing to include in a field guide. They add to the impression the book is from a different time where new standards are followed, but will not be good for unfamiliar readers who don't realize this area of the book represents Martyniuk's hopes instead of current thoughts (whereas while the Database uses e.g. Chiniaoae, I also explain its obscure origin). The fact Martyniuk erects a few new taxa (Ornithes, Ornithodesmiformes) and provides new definitions for many is also odd for a field guide, which are generally popular works where no new science is presented. The taxa and definitions are a mixed bag, with some being quite good but others quite bad, and my earlier post goes into those details. Above I mentioned that many unpublished ideas are used without comment, and quite a few of these are mine (Dromiceiomimus brevitertius being the right name for Ornithomimus edmontonicus, Zhongornis as a juvenile confuciusornithid, Omnivoropterygiformes having priority over Sapeornithiformes, Ichthyornis anceps being the correct name instead of I. dispar, possibly oviraptorosaurian Kuszholia, microraptorian Richardoestesia, dromaeosaurine Zapsalis, lithornithid Limenavis, etc.). On the one hand it's nice to have these out there and know people are listening to my ideas, and at least they aren't presented with arguments in technical papers. Still I would have liked credit for the more certain, creative ones, though I was acknowledged extensively in the book (my hesperornithine phylogeny which predated O'Connor and Zhou's, my idea on Dapingfangornis' supposed horn, my belief Yungavolucris may be synonymous with Elbretornis based on size). Jaime will be happy with some common names used for oviraptorids, like mitre-crested egg seizer and big-beaked shell thief.
While most of the information is accurate, there are some details I think are incorrect or unknown, mistakes, etc. in addition to the uncommon misspellings and such. Yet these issues are rare considering the vast amount of information in the book.
Martyniuk states "the snout of T. formosus would be more pointed at the tip as seen from above [than Saurornitholestes]", which I think was just a mistake, since the Troodon entry states it has a broad snout.
Not an error per se, but I notice Yixianosaurus is still in the basal oviraptorosaur cladogram but not mentioned in the text. No doubt it was accidentally left there after Martyniuk removed its entry, based on his blog post.
Incisivosaurus gauthieri is stated to be a probable synonym of Protarchaeopteryx robusta, but I don't think this has ever been suggested.
Skull details are given for Caudipteryx dongi, but it only preserves a frontal and pterygoid.
Microvenator is stated to be found in Oklahoma and Wyoming in addition to Montana (where the holotype was found), but only the holotype is known. It's also said to have a short tarsus, but only metatarsal I is preserved.
Chirostenotes elegans is presented as being a sexual variation of C. pergracilis. I'm not sure why recent authors are trying so hard to dissociate elegans from Elmisaurus, but they really do share characters. Note for example elegans doesn't have the diamond-shaped metatarsal III proximal section of C. pergracilis, which is even listed as a characteristic of the latter species by Martyniuk. Instead, the section is triangular as in E. rarus.
Paul's (2010) ideas on oviraptorid synonymy are given credence (though not followed), but are highly unlikely, even moreso given the recent osteology of Khaan (Balanoff and Norell, 2012) which details numerous differences from the Citipati holotype.
Cryptovolans' habitat and distribution are obviously supposed to be those of Hesperonychus, which was seemingly cut from the main section and accidentally not added to the end list of poorly known taxa.
Dromaeosaurus is described as having "Legs relatively long compared to contemporary S. explanatus. Tail more flexible than most other eudromaeosaurians.", but these areas are unknown. Indeed, Currie (2005) states some RTMP postcrania might be referrable to the genus because it is more robust than Saurornitholestes.
"Sickle claw very small" is listed as a feature of Adasaurus, but it turns out this is wrong (Kubota pers. comm. to Senter, 2010).
Timimus is listed as an unenlagiine, but was more recently determined to be a tyrannosauroid (Benson et al., 2012).
Buitreraptor was listed as having "wing claws short & digits nearly equal in length. Hand unusually short relative to very long humerus & radius/ulna." Yet this is based on the mount, which inaccurately restored the known fragments, which don't indicate any such morphology (Gianechini pers. comm.).
The tiny troodontid skulls from the Citipati nest are referred to Byronosaurus, but I believe the TWG team currently believes they belong to a more basal taxon like the Zos Canyon ?jinfengopterygiine (I'm sure I read this, but can't recall the source; they've gone back and forth so much on this).
"Legs long & slender." was listed as a trait of Zanabazar, but the preserved distal tibiotarsus and proximal tarsometatarsus leave this unknown.
Regarding Philovenator, "Additional specimens from the same time & general area, known as the “Zos Canyon Troodontid”, are probably the same species (Mortimer 2010)." It is nice to be credited, but I actually only "tentatively
referred" them to the same species. Since 2010, Philovenator has been redescribed and we have info on IGM 100/1280 (Zos Canyon specimen) and 100/1323 (both in Turner et al., 2012). So the idea could use reevaluation.
Euronychodon is in quotes, as is the genus of Paronychodon caperatus. I'm note sure of the rationale here.
Martyniuk states the "Diet is unknown in [Confuciusornis sanctus]" but consumed fish are preserved in one specimen (Dalsatt et al., 2006). It could be argued this is a different species as it is from a younger formation and shares a mandibular similarity with C. dui (as I state on my blog), but this is not elaborated in the book.
An "upturned bill tip" is stated as distinctive for C. dui, but is a keratinous bill actually known in C. sanctus? Even C. dui's premaxilla lacks an upcurved tip, after all.
Shenquiornis "Lacked procoracoid bones". Oops! Clearly just a typo.
Piksi, Palaeocursornis and Eurolimnornis are apparently pterosaurs (Agnolin and Varrichio, 2012), but this is forgivable as it was not published until after the book.
So overall this is an interesting book. As a field guide, it is quite good, far better than Paul's, but still falling short of Peterson's. It's so up to date it could be from the future, but the illustrations will make you think the author had access to the past. As a popular reference to bird origins, it is perhaps unmatched in quality, from feathers, to beaks to wings. It's even pretty good as an encyclopedia of maniraptorans for non-experts, since those rarely use internal details anyway. More questionable are its attempts to add to the repository of science. Some of the suggestions are good, others I dislike, but a field guide feels like the wrong place to publish them regardless. The price of the physical book ($36.99) is quite steep considering Peterson's field guides are $20-26, larger, and far more useful since Martyniuk's species will never actually be seen in the field. Similarly, though Paul's field guide is worse content-wise, it does contain skeletals, the whole range of Mesozoic non-pygostylian dinosaurs, and is hardcover at $35. But as a fun and educational introduction to the species of Mesozoic oviraptorosaurs and paravians, I can easily recommend the pdf version at its low price of $9.99. Thanks to Matt for trying this fascinating format!
Martyniuk, 2012. A Field Guide to Mesozoic Birds and Other Winged Dinosaurs. Vernon, New Jersey. Pan Aves. 189 pp.
Showing posts sorted by relevance for query Princeton Field Guide. Sort by date Show all posts
Showing posts sorted by relevance for query Princeton Field Guide. Sort by date Show all posts
Sunday, January 6, 2013
Wednesday, October 6, 2010
"The Princeton Field Guide to Dinosaurs" - The Review
One of the perks to working at a bookstore is being able to borrow books, and today I checked out Gregory S. Paul's newest work. My comments before have been based only on the snippets available on Google Books, which isn't exactly fair. I'm only going to concentrate on the theropod section for examples, since that's what I'm most familiar with.
When people think 'Gregory S. Paul', they think excellent skeletals and restorations, and this book's overflowing with them. My theropod favorites include Limusaurus, Acrocanthosaurus, Sinornithomimus, NGMC 2124, Sinocalliopteryx, Buitreraptor, Jinfengopteryx, Mei, the Two Medicine Troodon, Sapeornis and Protarchaeopteryx. One thing I like is how many are rigorous in showing only the known material. The unfortunate counterpoint is that that leaves one thinking the reconstructions which are complete indicate complete skeletons are known, but this is often not the case. I also liked the PDW way of illustrating skulls better, with thinner lines and texturing. The life restorations are spectacular as always. I love the Dromiceiomimus scraping eggs and the Sinosauropteryx leaping for a Confuciusornis as two modern updates to classic themes.
The other thing people think of when they hear 'Gregory S. Paul' is taxonomic lumping. ;) As I described in this post, he lumps a LOT of taxa together. I think this will be confusing to most readers, who won't realize a lot of these new combinations aren't found in the literature. While sometimes Paul notes what he changes in the taxonomy, he almost never states when something is his unique idea, or followed by other researchers. Interestingly on page 42 he states "The phylogeny and taxonomy offered here are not a formal proposal." This would seem to qualify for ICZN Article 8.2- A work that contains a statement to the effect that it is not issued for public and permanent scientific record, or for purposes of zoological nomenclature, is not published within the meaning of the Code. So perhaps Paul's new combinations are all nomina nuda.
Interestingly, Paul may lump genera and many species, but he also features a wide range of unnamed species. These include Padian's (1986) Coelophysis, the supposed Morrison Elaphrosaurus, Portuguese Ceratosaurus, problematic long-snouted Allosaurus, Dinosaur Park and Two Medicine Daspletosaurus, Dinosaur Park Struthiomimus, NGMC 2124, and Triebold and Horseshoe Canyon caenagnathids. While some of these have been proposed in the literature, others haven't and seem to be largely stratigraphy-based. I think the space would have been better spent including additional named taxa, such as Halticosaurus, Genyodectes, Betasuchus, Velocisaurus, Chuandongocoelurus, Erectopus, Metriacanthosaurus, Becklespinax, Archaeornithoides, Variraptor, Borogovia, etc..
The first 63 pages consist of standard introductory material- anatomy, behavior, trackways, history, extinction, etc.. It's largely what one finds in many dinosaur books, but is more accurate than any others I can recall. One unique section is "Dinosaur Safari", which playfully imagines how human time travelers might deal with the Mesozoic. I do think the book could have benefited from an additional editor besides Kirkland, as there are occasional typos (the Landian stage of the Middle Triassic, Pycnoneosaurus, Ricardoesteria, protoarchaeopterygids, etc.). Also the accuracy of the temporal distribution of different groups on the timescale of pages 64-65 is subpar, with most maniraptoriform clades appearing too late for instance.
The main portion of the book is of course the taxonomic section. I stand by my previous complaint that this is not effective as a field guide, since nearly all the taxa lack any useful description or indication of diagnostic features. It's more like Sattler's 1983 "The Illustrated Dinosaur Dictionary" or Lambert's 1990 "The Dinosaur Data Book", with less information on each taxon than the former, but much more than the latter. It's also more technical than either in including species, stages, formations and more anatomical terms. Yet it's also less complete than either, and while obviously you can't reconstruct Ornithodesmus or Bradycneme, I don't think I'm alone among dinosaur enthusiasts in wanting my books to include every taxon.
The descriptions that do exist are often so vague as to be pointless. For instance, coelurosaurs are described as follows- "Highly variable. Tail long to very short. Arm from longer than leg to severely reduced. Leg extremely gracile to robust, toes four to three." Well... I guess some amphiumas and sloths are excluded at least. ;) That doesn't tell you anything about what distinguishes the group. The individual species descriptions suffer the same problem, when they mention any features at all. And a disturbingly large number of taxa are merely said to be standard for their group, including rather distinctive ones such as Herrerasaurus, Segisaurus, Noasaurus, Torvosaurus, Piatnitzkysaurus, Eustreptospondylus, Gasosaurus, Siamotyannus, sinraptorids, Carcharodontosaurus, Giganotosaurus, Mapusaurus, Mononykus, Mahakala, Sinornithoides, Nanshiungosaurus and Erliansaurus. Others are said to have insufficient information, but it's inconsistantly applied. While Duriavenator and Ilokelesia get a description, Elaphrosaurus, Elmisaurus and Neimongosaurus don't.
The theropod groups (Theropoda, Tetanurae, Coelurosauria, Maniraptora, etc.) are never implied to include pygostylians in the introductory sections, so reading that e.g. maniraptorans only lasted to "the end of the dinosaur era" is rather odd. All major theropod taxa have the following in their notes- "absence from Antarctica probably reflects lack of sufficient sampling." Not only is it repetitive, it's unecessary since we have both Molnar et al.'s (1996) basal tetanurine tibia and Case et al.'s (2007) supposed dromaeosaur from the continent. The habits section gets particularily speculative. For instance, herrerasaurs are said to be pursuit predators. Really? Of the included taxa, Alwalkeria and Chindesaurus are far too poorly known, Eoraptor seems omnivorous and Herrerasaurus is massively built with shorter tibiae than femora. I suppose Staurikosaurus may have been, but the topic has never been studied to my knowledge. One excellent practice is taxa known only from young specimens aren't given a size and are instead marked "Adult size not certain."
"The Princeton Field Guide to Dinosaurs" is thus extremely accurate in general and full of amazing artwork, but isn't very useful for learning about individual dinosaur species or groups. It also contains a lot of information which is not based on the literature and often contradicts the consensus, which most readers won't know. I'd recommend it for young readers who aren't ready for Glut's encyclopedias or The Dinosauria yet.
Next up, theropod criticism and commentary.
Paul, 2010. The Princeton Field Guide to Dinosaurs. Princeton University Press. 320 pp.
When people think 'Gregory S. Paul', they think excellent skeletals and restorations, and this book's overflowing with them. My theropod favorites include Limusaurus, Acrocanthosaurus, Sinornithomimus, NGMC 2124, Sinocalliopteryx, Buitreraptor, Jinfengopteryx, Mei, the Two Medicine Troodon, Sapeornis and Protarchaeopteryx. One thing I like is how many are rigorous in showing only the known material. The unfortunate counterpoint is that that leaves one thinking the reconstructions which are complete indicate complete skeletons are known, but this is often not the case. I also liked the PDW way of illustrating skulls better, with thinner lines and texturing. The life restorations are spectacular as always. I love the Dromiceiomimus scraping eggs and the Sinosauropteryx leaping for a Confuciusornis as two modern updates to classic themes.
The other thing people think of when they hear 'Gregory S. Paul' is taxonomic lumping. ;) As I described in this post, he lumps a LOT of taxa together. I think this will be confusing to most readers, who won't realize a lot of these new combinations aren't found in the literature. While sometimes Paul notes what he changes in the taxonomy, he almost never states when something is his unique idea, or followed by other researchers. Interestingly on page 42 he states "The phylogeny and taxonomy offered here are not a formal proposal." This would seem to qualify for ICZN Article 8.2- A work that contains a statement to the effect that it is not issued for public and permanent scientific record, or for purposes of zoological nomenclature, is not published within the meaning of the Code. So perhaps Paul's new combinations are all nomina nuda.
Interestingly, Paul may lump genera and many species, but he also features a wide range of unnamed species. These include Padian's (1986) Coelophysis, the supposed Morrison Elaphrosaurus, Portuguese Ceratosaurus, problematic long-snouted Allosaurus, Dinosaur Park and Two Medicine Daspletosaurus, Dinosaur Park Struthiomimus, NGMC 2124, and Triebold and Horseshoe Canyon caenagnathids. While some of these have been proposed in the literature, others haven't and seem to be largely stratigraphy-based. I think the space would have been better spent including additional named taxa, such as Halticosaurus, Genyodectes, Betasuchus, Velocisaurus, Chuandongocoelurus, Erectopus, Metriacanthosaurus, Becklespinax, Archaeornithoides, Variraptor, Borogovia, etc..
The first 63 pages consist of standard introductory material- anatomy, behavior, trackways, history, extinction, etc.. It's largely what one finds in many dinosaur books, but is more accurate than any others I can recall. One unique section is "Dinosaur Safari", which playfully imagines how human time travelers might deal with the Mesozoic. I do think the book could have benefited from an additional editor besides Kirkland, as there are occasional typos (the Landian stage of the Middle Triassic, Pycnoneosaurus, Ricardoesteria, protoarchaeopterygids, etc.). Also the accuracy of the temporal distribution of different groups on the timescale of pages 64-65 is subpar, with most maniraptoriform clades appearing too late for instance.
The main portion of the book is of course the taxonomic section. I stand by my previous complaint that this is not effective as a field guide, since nearly all the taxa lack any useful description or indication of diagnostic features. It's more like Sattler's 1983 "The Illustrated Dinosaur Dictionary" or Lambert's 1990 "The Dinosaur Data Book", with less information on each taxon than the former, but much more than the latter. It's also more technical than either in including species, stages, formations and more anatomical terms. Yet it's also less complete than either, and while obviously you can't reconstruct Ornithodesmus or Bradycneme, I don't think I'm alone among dinosaur enthusiasts in wanting my books to include every taxon.
The descriptions that do exist are often so vague as to be pointless. For instance, coelurosaurs are described as follows- "Highly variable. Tail long to very short. Arm from longer than leg to severely reduced. Leg extremely gracile to robust, toes four to three." Well... I guess some amphiumas and sloths are excluded at least. ;) That doesn't tell you anything about what distinguishes the group. The individual species descriptions suffer the same problem, when they mention any features at all. And a disturbingly large number of taxa are merely said to be standard for their group, including rather distinctive ones such as Herrerasaurus, Segisaurus, Noasaurus, Torvosaurus, Piatnitzkysaurus, Eustreptospondylus, Gasosaurus, Siamotyannus, sinraptorids, Carcharodontosaurus, Giganotosaurus, Mapusaurus, Mononykus, Mahakala, Sinornithoides, Nanshiungosaurus and Erliansaurus. Others are said to have insufficient information, but it's inconsistantly applied. While Duriavenator and Ilokelesia get a description, Elaphrosaurus, Elmisaurus and Neimongosaurus don't.
The theropod groups (Theropoda, Tetanurae, Coelurosauria, Maniraptora, etc.) are never implied to include pygostylians in the introductory sections, so reading that e.g. maniraptorans only lasted to "the end of the dinosaur era" is rather odd. All major theropod taxa have the following in their notes- "absence from Antarctica probably reflects lack of sufficient sampling." Not only is it repetitive, it's unecessary since we have both Molnar et al.'s (1996) basal tetanurine tibia and Case et al.'s (2007) supposed dromaeosaur from the continent. The habits section gets particularily speculative. For instance, herrerasaurs are said to be pursuit predators. Really? Of the included taxa, Alwalkeria and Chindesaurus are far too poorly known, Eoraptor seems omnivorous and Herrerasaurus is massively built with shorter tibiae than femora. I suppose Staurikosaurus may have been, but the topic has never been studied to my knowledge. One excellent practice is taxa known only from young specimens aren't given a size and are instead marked "Adult size not certain."
"The Princeton Field Guide to Dinosaurs" is thus extremely accurate in general and full of amazing artwork, but isn't very useful for learning about individual dinosaur species or groups. It also contains a lot of information which is not based on the literature and often contradicts the consensus, which most readers won't know. I'd recommend it for young readers who aren't ready for Glut's encyclopedias or The Dinosauria yet.
Next up, theropod criticism and commentary.
Paul, 2010. The Princeton Field Guide to Dinosaurs. Princeton University Press. 320 pp.
Tuesday, August 3, 2010
GSP's new taxon combinations from his dinosaur field guide
Taking a break from non-theropods, I checked out the Google Books preview for Gregory S. Paul's new The Princeton Field Guide to Dinosaurs. While I'm still disappointed in the basic layout of the book, I'm impressed by just how many new taxa Paul's managed to include, and the new skeletal reconstructions are awesome. As anyone who's read PDW should expect, Paul creates a ton of new genus-species combinations in this volume. Someone more well versed with sauropodomorphs and ornithischians will have to handle those clades, but what follows is a discussion of his new theropod names.
Abelisaurus garridoi- Instead of Aucasaurus. This could very well be true, but since Abelisaurus' skull was only described briefly and before other abelisaurids were recognized, and Aucasaurus' skull remains undescribed and schematically illustrated, it seems premature.
Allosaurus antunesi- Instead of Lourinhanosaurus. Now this one's problematic. Lourinhanosaurus has never even been hypothesized to be an allosaurid, and phylogenetic analyses suggest it is a more basal carnosaur or even a megalosauroid. Most recently, Benson et al. (2010) found it to be sister to Streptospondylus.
Streptospondylus nethercombensis- Instead of Magnosaurus. I should note that Paul also sinks Eustreptospondylus oxoniensis into Streptospondylus altdorfensis. The latter two species were placed as sister taxa by Allain (2002) and Smith et al. (2007) based on the presence of carotid processes in their anterior dorsal vertebrae, but it seems the feature is barely developed in Eustreptospondylus (Sadlier et al., 2008). The superior analysis of Benson et al. (2010) found Streptospondylus to be closer to Lourinhanosaurus, and a carnosaur instead of a megalosauroid. Sadlier et al.'s and Benson's recent papers have shown Rauhut's (2003) proposed relationship of Eustreptospondylus to Magnosaurus isn't as close as he thought, so sinking Eustreptospondylus without sinking Duriavenator and such seems unwise.
Carcharodontosaurus carolinii- Instead of Giganotosaurus. It turns out Paul was not the first to publish this combination, that honor going to Figueiredo, 1998, but the latter is so muddled that Paul can be said to be the first to competently publish it. ;) In any case, this is one of those subjective decisions. The problem is that most analyses agree Mapusaurus is closer to Giganotosaurus than to Carcharodontosaurus. So to sink Giganotosaurus you'd need to sink Mapusaurus too.
Monolophosaurus wucaii- Instead of Guanlong. Er, this I seriously doubt. I know Carr (2006) proposed Guanlong is a juvenile Monolophosaurus, but Paul doesn't think this is true. They don't emerge as closely related in any analysis except for Carr's (e.g. Rauhut's, Benson's).
Struthiomimus edmontonicus- Instead of Ornithomimus. Paul's given up his PDW synonymization of all ornithomimid genera, but edmontonicus is a junior synonym of brevitertius, and there is no evidence this species is closer to Struthiomimus than to Ornithomimus, Anserimimus or Gallimimus for instance.
Caudipteryx yixianensis- Instead of Similicaudipteryx. The problem here is that all the proposed similarities with Caudipteryx are symplesiomorphies. Similicaudipteryx shares some synapomorphies with caenagnathids in my analysis, though the new specimens could affect this.
Citipati barsboldi, gracilis, huangi and mongoliensis- Instead of Nemegtomaia, Conchoraptor, Heyuannia and Rinchenia. Synonymize derived oviraptorid genera if you like, but Conchoraptor has priority over Citipati. Paul seems to think Conchoraptor gracilis and "Ingenia" yanshini are synonyms, so yanshini should be the name he uses for that species. Where's Khaan you ask? A juvenile of Citipati osmolskae according to Paul. I bet Jaime will have some harsh words for these synonymies.
Sinornithosaurus ashile, lujiatunensis and zhaoianus- Instead of Shanag, Graciliraptor and Microraptor. Much like the previous example, making all microraptorians one genus is a subjective choice. Yet Hesperonychus was not sunk, and there is no evidence it's outside the clade formed by the above species. Shanag's placement as a microraptorian is also questionable. Another issue is that Richardoestesia is extremely similar to Sinornithosaurus and Shanag, but would have priority if all of these genera were synonymized. Better to keep them separate in my opinion.
Velociraptor mangas- Instead of Tsaagan. This is problematic since Tsaagan was most recently placed as sister to Adasaurus (Longrich and Currie, 2009) or as basal to Eudromaeosauria (Senter, 2007).
These examples indicate the general problems with synonymizing Mesozoic dinosaur genera. I agree Mesozoic dinosaurs are oversplit compared to recent taxa, and I've been a big proponent of synonymizing species (Alioramus altai, Didactylornis jii, etc.). But when it comes to genera, you first have to be sure they form a monophyletic group. I'd say most of Paul's new combinations fail at this. Even if they do form a clade, you run the risk of having an earlier-named genus ending up in it. Richardoestesia as a microraptorine was an example above, and Suchosaurus is another if you want to sink Cristatusaurus into Baryonyx. This makes our current monospecific dinosaur genus trend more stable. And even if you have a perfectly stable clade of species, you have to ask yourself what the point of synonymization is. Paul's Carcharodontosaurus is already Carcharodontosaurinae, his Sinornithosaurus is already Microraptoria. So it doesn't increase the ease of communication, and it misleadingly implies a similarity greater than that between other sister genera. Are Microraptor and Sinornithosaurus more similar to each other than Achillobator is to Utahraptor, for instance? Who can say? All you end up doing is forming instability compared to past publications and sinking a name someone else published.
Paul, 2010. The Princeton Field Guide to Dinosaurs. Princeton University Press. 320 pp.
Abelisaurus garridoi- Instead of Aucasaurus. This could very well be true, but since Abelisaurus' skull was only described briefly and before other abelisaurids were recognized, and Aucasaurus' skull remains undescribed and schematically illustrated, it seems premature.
Allosaurus antunesi- Instead of Lourinhanosaurus. Now this one's problematic. Lourinhanosaurus has never even been hypothesized to be an allosaurid, and phylogenetic analyses suggest it is a more basal carnosaur or even a megalosauroid. Most recently, Benson et al. (2010) found it to be sister to Streptospondylus.
Streptospondylus nethercombensis- Instead of Magnosaurus. I should note that Paul also sinks Eustreptospondylus oxoniensis into Streptospondylus altdorfensis. The latter two species were placed as sister taxa by Allain (2002) and Smith et al. (2007) based on the presence of carotid processes in their anterior dorsal vertebrae, but it seems the feature is barely developed in Eustreptospondylus (Sadlier et al., 2008). The superior analysis of Benson et al. (2010) found Streptospondylus to be closer to Lourinhanosaurus, and a carnosaur instead of a megalosauroid. Sadlier et al.'s and Benson's recent papers have shown Rauhut's (2003) proposed relationship of Eustreptospondylus to Magnosaurus isn't as close as he thought, so sinking Eustreptospondylus without sinking Duriavenator and such seems unwise.
Carcharodontosaurus carolinii- Instead of Giganotosaurus. It turns out Paul was not the first to publish this combination, that honor going to Figueiredo, 1998, but the latter is so muddled that Paul can be said to be the first to competently publish it. ;) In any case, this is one of those subjective decisions. The problem is that most analyses agree Mapusaurus is closer to Giganotosaurus than to Carcharodontosaurus. So to sink Giganotosaurus you'd need to sink Mapusaurus too.
Monolophosaurus wucaii- Instead of Guanlong. Er, this I seriously doubt. I know Carr (2006) proposed Guanlong is a juvenile Monolophosaurus, but Paul doesn't think this is true. They don't emerge as closely related in any analysis except for Carr's (e.g. Rauhut's, Benson's).
Struthiomimus edmontonicus- Instead of Ornithomimus. Paul's given up his PDW synonymization of all ornithomimid genera, but edmontonicus is a junior synonym of brevitertius, and there is no evidence this species is closer to Struthiomimus than to Ornithomimus, Anserimimus or Gallimimus for instance.
Caudipteryx yixianensis- Instead of Similicaudipteryx. The problem here is that all the proposed similarities with Caudipteryx are symplesiomorphies. Similicaudipteryx shares some synapomorphies with caenagnathids in my analysis, though the new specimens could affect this.
Citipati barsboldi, gracilis, huangi and mongoliensis- Instead of Nemegtomaia, Conchoraptor, Heyuannia and Rinchenia. Synonymize derived oviraptorid genera if you like, but Conchoraptor has priority over Citipati. Paul seems to think Conchoraptor gracilis and "Ingenia" yanshini are synonyms, so yanshini should be the name he uses for that species. Where's Khaan you ask? A juvenile of Citipati osmolskae according to Paul. I bet Jaime will have some harsh words for these synonymies.
Sinornithosaurus ashile, lujiatunensis and zhaoianus- Instead of Shanag, Graciliraptor and Microraptor. Much like the previous example, making all microraptorians one genus is a subjective choice. Yet Hesperonychus was not sunk, and there is no evidence it's outside the clade formed by the above species. Shanag's placement as a microraptorian is also questionable. Another issue is that Richardoestesia is extremely similar to Sinornithosaurus and Shanag, but would have priority if all of these genera were synonymized. Better to keep them separate in my opinion.
Velociraptor mangas- Instead of Tsaagan. This is problematic since Tsaagan was most recently placed as sister to Adasaurus (Longrich and Currie, 2009) or as basal to Eudromaeosauria (Senter, 2007).
These examples indicate the general problems with synonymizing Mesozoic dinosaur genera. I agree Mesozoic dinosaurs are oversplit compared to recent taxa, and I've been a big proponent of synonymizing species (Alioramus altai, Didactylornis jii, etc.). But when it comes to genera, you first have to be sure they form a monophyletic group. I'd say most of Paul's new combinations fail at this. Even if they do form a clade, you run the risk of having an earlier-named genus ending up in it. Richardoestesia as a microraptorine was an example above, and Suchosaurus is another if you want to sink Cristatusaurus into Baryonyx. This makes our current monospecific dinosaur genus trend more stable. And even if you have a perfectly stable clade of species, you have to ask yourself what the point of synonymization is. Paul's Carcharodontosaurus is already Carcharodontosaurinae, his Sinornithosaurus is already Microraptoria. So it doesn't increase the ease of communication, and it misleadingly implies a similarity greater than that between other sister genera. Are Microraptor and Sinornithosaurus more similar to each other than Achillobator is to Utahraptor, for instance? Who can say? All you end up doing is forming instability compared to past publications and sinking a name someone else published.
Paul, 2010. The Princeton Field Guide to Dinosaurs. Princeton University Press. 320 pp.
Friday, October 8, 2010
"The Princeton Field Guide to Dinosaurs" - The Sauropodomorphs
Part 3 of the review series, I should preface this by saying that sauropodomorphs aren't my speciality. I don't follow the literature closely, so I don't know if some of Paul's nonstandard ideas have been proposed before, or how likely they are to be correct.
As with the theropods, the reconstructions are plentiful. My favorites include Massospondylus, Lufengosaurus, Yunnanosarus, Jingshanosaurus, Riojasaurus, Gongxianosaurus, Datousaurus, Cetiosaurus and Atlasaurus.
Among non-sauropods, Paul doesn't follow the consensus in a few areas. Ammosaurus is listed separately from Anchisaurus, Ruehleia is said to be an adult Plateosaurus longiceps, Efraasia is back to being a juvenile Plateosaurus gracilis and P. longiceps is kept separate from P. engelhardti. He only does a little lumping, with "Massospondylus (or Plateosaurus = Lufengosaurus) huenei" and "Massospondylus (or Plateosaurus) carinatus". Plateosaurus is usually not in an exclusive clade with Lufengosaurus and Massospondylus, so this seems like an improper synonymy. Even synonymizing Lufengosaurus with Massospondylus seems wrong if Adeopapposaurus and Coloradisaurus are retained in their own genera. In the first of a few examples to be noted here, Paul says Plateosauravus cullingworthi "was Euskelosaurus browni, which is based on inadequate remains." Argh. Euskelosaurus can't become Plateosauravus since the former has priority. According to Yates (2004), Euskelosaurus really is indeterminate and could belong to Plateosauravus or an undescribed prosauropod from the Clocolan District.
Among sauropods, Klamelisaurus is treated as adult Bellusaurus, which I know was suggested, but has anyone actually examined this issue? The mamenchisaurids suffer quite the deconstruction. I agree with Paul that the alpha taxonomy on these things needs to be examined, but since Paul's rationale is never explained and even his intent is sometimes ambiguous, I can't say he sheds much light on the issue. tianfuensis is said not to be Omeisaurus (it is "too different"), while maoianus is placed in the genus with a question mark. hochuanensis and youngi are both said to be in the same genus and perhaps just different sexes of the same species. They're also excluded from Mamenchisaurus based in part on M. constructus having a shorter neck, though I was under the impression M. constructus' cervicals were simply incomplete so restored as being short. Paul also lists (quotation marks his) "Mamenchisaurus" anyuensis, "Mamenchisaurus sinocanadorum" and "Mamenchisaurus jingyanensis." The latter is said to probably belong to one of the other Shangshaximiao species. While the quotation marks would seem to indicate Paul doesn't think anyuensis belongs in Mamenchisaurus, I'm not sure what they imply for sinocanadorum and jingyanensis (both were properly described, so are not nomina nuda).
Among diplodocids, Paul lists "Amphicoelias or Diplodocus altus" and says "Status not certain, may be a distinct genus or Diplodocus." Ack again. Diplodocus altus can never exist, as Amphicoelias has priority over it. There's an unnamed species of Diplodocus listed from Utah represented by "two skulls and majority of a few skeletons." It's illustrated with a complete skeleton and is listed separately from D. longus, D. carnegii, D. hayi and D. halli (wasn't this emmended to hallorum?). Anyone know if the literature supports this? Paul seems to place Apatosaurus parvus, A. excelsus and A. louisae in the subgenus Brontosaurus, which contradicts Upchurch et al.'s (2004) study that found parvus and excelsus to be closer to ajax than to louisae. His statement "Brontosaurus is the shorter, narrower necked version of Apatosaurus from the lower and middle Morrison" wouldn't be agreed on by sauropod experts as far as I know. It's these kinds of statements which make me cringe imagining kids reading the book, since they're just stated as true despite being found nowhere in the literature.
Paul excludes ruyangensis from Huanghetitan and giganteus from Antarctosaurus. Pitekunsaurus is said to be "probably a juvenile of one of the other Anacleto titanosaurs." I have no idea is these things are plausible. While I can never keep track of the metric crapload of titanosaurs being described these days, things like placing Isisaurus outside Lithostrotia but including Huabeisaurus don't seem to mesh with even the pitiful amount of consensus that has been reached regarding their phylogeny. I also don't think the evidence justifies synonymizing Opisthocoelicaudia skarzynskii with Nemegtosaurus mongoliensis or placing Quaesitosaurus in the same genus. It's not like formations with more than one sauropod are uncommon, and I'm doubtful Nemegtosaurus' sister genera have skulls preserved. Finally, Pleurocoelus is said to be "originally Astrodon johnstoni, which was based on inadequate remains." But just like with Euskelosaurus, Astrodon has priority over Pleurocoelus so can never become Pleurocoelus.
Next up, ornithischians *yawn* ;)
As with the theropods, the reconstructions are plentiful. My favorites include Massospondylus, Lufengosaurus, Yunnanosarus, Jingshanosaurus, Riojasaurus, Gongxianosaurus, Datousaurus, Cetiosaurus and Atlasaurus.
Among non-sauropods, Paul doesn't follow the consensus in a few areas. Ammosaurus is listed separately from Anchisaurus, Ruehleia is said to be an adult Plateosaurus longiceps, Efraasia is back to being a juvenile Plateosaurus gracilis and P. longiceps is kept separate from P. engelhardti. He only does a little lumping, with "Massospondylus (or Plateosaurus = Lufengosaurus) huenei" and "Massospondylus (or Plateosaurus) carinatus". Plateosaurus is usually not in an exclusive clade with Lufengosaurus and Massospondylus, so this seems like an improper synonymy. Even synonymizing Lufengosaurus with Massospondylus seems wrong if Adeopapposaurus and Coloradisaurus are retained in their own genera. In the first of a few examples to be noted here, Paul says Plateosauravus cullingworthi "was Euskelosaurus browni, which is based on inadequate remains." Argh. Euskelosaurus can't become Plateosauravus since the former has priority. According to Yates (2004), Euskelosaurus really is indeterminate and could belong to Plateosauravus or an undescribed prosauropod from the Clocolan District.
Among sauropods, Klamelisaurus is treated as adult Bellusaurus, which I know was suggested, but has anyone actually examined this issue? The mamenchisaurids suffer quite the deconstruction. I agree with Paul that the alpha taxonomy on these things needs to be examined, but since Paul's rationale is never explained and even his intent is sometimes ambiguous, I can't say he sheds much light on the issue. tianfuensis is said not to be Omeisaurus (it is "too different"), while maoianus is placed in the genus with a question mark. hochuanensis and youngi are both said to be in the same genus and perhaps just different sexes of the same species. They're also excluded from Mamenchisaurus based in part on M. constructus having a shorter neck, though I was under the impression M. constructus' cervicals were simply incomplete so restored as being short. Paul also lists (quotation marks his) "Mamenchisaurus" anyuensis, "Mamenchisaurus sinocanadorum" and "Mamenchisaurus jingyanensis." The latter is said to probably belong to one of the other Shangshaximiao species. While the quotation marks would seem to indicate Paul doesn't think anyuensis belongs in Mamenchisaurus, I'm not sure what they imply for sinocanadorum and jingyanensis (both were properly described, so are not nomina nuda).
Among diplodocids, Paul lists "Amphicoelias or Diplodocus altus" and says "Status not certain, may be a distinct genus or Diplodocus." Ack again. Diplodocus altus can never exist, as Amphicoelias has priority over it. There's an unnamed species of Diplodocus listed from Utah represented by "two skulls and majority of a few skeletons." It's illustrated with a complete skeleton and is listed separately from D. longus, D. carnegii, D. hayi and D. halli (wasn't this emmended to hallorum?). Anyone know if the literature supports this? Paul seems to place Apatosaurus parvus, A. excelsus and A. louisae in the subgenus Brontosaurus, which contradicts Upchurch et al.'s (2004) study that found parvus and excelsus to be closer to ajax than to louisae. His statement "Brontosaurus is the shorter, narrower necked version of Apatosaurus from the lower and middle Morrison" wouldn't be agreed on by sauropod experts as far as I know. It's these kinds of statements which make me cringe imagining kids reading the book, since they're just stated as true despite being found nowhere in the literature.
Paul excludes ruyangensis from Huanghetitan and giganteus from Antarctosaurus. Pitekunsaurus is said to be "probably a juvenile of one of the other Anacleto titanosaurs." I have no idea is these things are plausible. While I can never keep track of the metric crapload of titanosaurs being described these days, things like placing Isisaurus outside Lithostrotia but including Huabeisaurus don't seem to mesh with even the pitiful amount of consensus that has been reached regarding their phylogeny. I also don't think the evidence justifies synonymizing Opisthocoelicaudia skarzynskii with Nemegtosaurus mongoliensis or placing Quaesitosaurus in the same genus. It's not like formations with more than one sauropod are uncommon, and I'm doubtful Nemegtosaurus' sister genera have skulls preserved. Finally, Pleurocoelus is said to be "originally Astrodon johnstoni, which was based on inadequate remains." But just like with Euskelosaurus, Astrodon has priority over Pleurocoelus so can never become Pleurocoelus.
Next up, ornithischians *yawn* ;)
Thursday, October 7, 2010
"The Princeton Field Guide to Dinosaurs - The Theropods
Having reviewed Paul's new book in the last post, this one will examine the good, bad and just plain interesting things it has to say about theropods. It's organized in the order Paul discusses the taxa.
The seemingly rigorous Staurikosaurus skeletal includes anterior cervicals, chevrons, the whole pectoral girdle, a humerus and pes.
The coelophysoids have meager descriptions as with most taxa, but most every skulless one (Procompsognathus, Podokesaurus, Gojirasaurus, Liliensternus, Segisaurus, but not Lophostropheus) contains the phrase "not known whether head crests were present." This is repetitive (it would be simpler to say only Megapnosaurus and Coelophysis are known to LACK crests) and you would think there's more useful information the space could be spent on, like Gojirasaurus being a chimaera, Procompsognathus being perhaps nondinosaurian and with a controversial skull, Segisaurus being thought to have solid bones and unfused clavicles until recently, etc..
Among abelisaurs, the Rahiolisaurus skeleton is labeled Indosuchus and seems to just be reposed from Chatterjee and Rudra's schematic drawing (which is now known to be wrong in various ways thanks to the description). A complete skull is illustrated and listed for Rajasaurus, but while there is a cast that's often photographed, only a braincase is present according to the description. For those curious why Aucasaurus is sunk into Abelisaurus- "the only reason this does not appear to be a juvenile A. comahuensis is that fusion of skeletal elements suggests it is an adult." It should be noted Paul has an odd phylogeny where ceratosaurids and elaphrosaurs are closer to tetanurines than abelisauroids are. The seemingly rigorous Elaphrosaurus skeletal incorrectly has a complete vertebral column, all chevrons (only one is preserved) and complete pes, but doesn't include the scapulocoracoid or metacarpals.
Poekilopleuron bucklandii being the same genus and/or species as Megalosaurus bucklandii might have been a viable idea back in 1988, but not now that both have been redescribed. Another odd aspect to Paul's phylogeny is that Piatnitzkysaurus, Condorraptor, Magnosaurus, Eustreptospondylus (as Streptospondylus) and Afrovenator are avetheropods. The rationale for sinking Eustreptospondylus- "Eustreptospondylus oxoniensis is tentatively placed in Streptospondylus altdorfensis." Eustreptospondylus' skeletal is odd in lacking most of the skull besides the premaxilla, maxilla and quadrate, but a lot of what is shown is not preserved (ribs, most caudal vertebrae, chevrons, etc.).
Sinraptor hepingensis is synonymized with Yangchuanosaurus shangyouensis, but S. dongi (with a humerus and coracoid in its rigorous skeletal) is kept separate. Monolophosaurus and Guanlong are both sinraptorids, which has never been supported to my knowledge. Paul retains the old short snout vs. long snout Allosaurus dichotomy which Chure has showed is untrue. For Neovenator, he states "That researchers have disagreed whether this is a basal tyrannosauroid or an allosauroid suggests these groups may be more closely related than thought." But whoever proposed Neovenator is a tyrannosauroid?
For Coelurosauria, Paul states "The validity of the group is not certain." But who has ever had a theropod phylogeny without it? While I do applaud Paul's indicating when taxa are based on juvenile specimens, he's incorrect in calling the heavily fused Bagaraatan type a juvenile and the young Raptorex type an adult. On the other hand, I was happy to see him call both Alioramus species juveniles and probably synonymous. One new combination missing in my taxonomy post is "Appalachiosaurus (or Albertosaurus) montgomeriensis." Using Carr's data, that seems fine as long as Bistahieversor is Albertosaurus too.
Paul lumps all American ornithomimids into Struthiomimus, but says Struthiomimus? sedens "includes Ornithomimus velox, which is based on entirely inadequate remains." GAK!!! Impossible. Ornithomimus and the species velox have priority over Struthiomimus and sedens. If Ornithomimus' syntypes are entirely inadequate (and they're not), it couldn't be assigned to the same species as sedens.
The rigorous Ornitholestes skeletal lacks any forearm or manus material (even though the famous manus has been reassigned to Tanycolagreus, the holotype has manus material as well). Scansoriopteryx is used instead of Epidendrosaurus, which is nice. Yet the taxon is not placed with Epidexipteryx, as the latter is assigned to Oviraptorosauria instead. Wherever the taxa belong, their morphology is so similar that they may even be synonymous. If Paul would have used all the manual phalanges in Epidexipteryx, he would have found it impossible to restore with normal hands.
Shanag is sunk into Sinornithosaurus because "Too little is known to distinguish this from Sinornithosaurus." Tsaagan and Graciliraptor don't even get that much explanation. Deinonychus' skeletal is oddly incomplete (no scapula, humerus, ilium, pubis, femur, tibia or fibula), which I'm assuming is due to Paul's statement Lower Cloverly remains "are probably one or more different taxa."
The oviraptorosaurs are all given bifurcated tail fans, but Gatesy (2001) showed this was an illusion in Caudipteryx. Both Epidexipteryx and omnivoropterygids are placed in Oviraptorosauria, which has never been supported by an analysis, but I do like that Paul uses Omnivoropterygidae instead of Sapeornithidae. The caenagnathid taxonomy is highly confused. Using Paul's names, it consists of- Caenagnathus collinsi (only the type mandible), Caenagnathus? sp. (the two undescribed Triebold skeletons), Chirostenotes pergracilis (said to possibly include elegans), Chirostenotes? sp. (the specimen described in Sues, 1997), and Elmisaurus (or Chirostenotes) rarus. Where to begin? The Triebold skeletons combine Caenagnathus jaws with Chirostenotes postcrania, so there's no reason to keep the genera separate, let alone refer the Triebold material to one genus or the other. elegans is more similar to Elmisaurus despite the undefended assertions of some recent papers (Sues, 1997; Maryanska et al., 2002; Osmolska et al., 2004). The Horseshoe Canyon specimen described by Sues has never been suggested to belong to a distinct taxon in the literature, and was seemingly just separated based on stratigraphy. Shanyangosaurus is listed as a caenagnathid, which I find amusing since I suggested it was an oviraptorosaur back in 2000, that was also followed by Holtz et al. (2004). Ironically, I no longer think my analysis was sufficient to place it anywhere specific within Maniraptora.
Oviraptorids themselves were lumped a lot. For Citipati osmolskae, Paul says "It is probable that crestless Khaan mckennai is the juvenile form of this species." And for "Conchoraptor (or Citipati) gracilis", he says "It is probable that all specimens from this formation are juveniles and adults of one species whose taxonomy is complicated because the genus portion of the original name Ingenia yanshini turned out to be preoccupied by an invertebrate." But as I noted before, just because Ingenia is preoccupied doesn't mean yanshini wouldn't still be the species name. Nor can Conchoraptor gracilis ever be Citipati gracilis, since Conchoraptor has priority over Citipati. His illustration for this conglomerate of taxa is basically "Ingenia" but with that privately owned skull with the very tall pointed crest. I do like that Paul illustrates the internal nostrils on the side of the ventrally projected palate in oviraptorids.
The reconstruction of Beipiaosaurus uses the new anterior skeleton and features a silly-looking vaguely stegosaur-like skull with a pointy snout. Contra to Paul who thinks Nothronychus graffami (mistyped grafmani) might be synonymous with N. mckinleyi, I'm doubtful they're even congeneric.
Next up, sauropodomorphs...
The seemingly rigorous Staurikosaurus skeletal includes anterior cervicals, chevrons, the whole pectoral girdle, a humerus and pes.
The coelophysoids have meager descriptions as with most taxa, but most every skulless one (Procompsognathus, Podokesaurus, Gojirasaurus, Liliensternus, Segisaurus, but not Lophostropheus) contains the phrase "not known whether head crests were present." This is repetitive (it would be simpler to say only Megapnosaurus and Coelophysis are known to LACK crests) and you would think there's more useful information the space could be spent on, like Gojirasaurus being a chimaera, Procompsognathus being perhaps nondinosaurian and with a controversial skull, Segisaurus being thought to have solid bones and unfused clavicles until recently, etc..
Among abelisaurs, the Rahiolisaurus skeleton is labeled Indosuchus and seems to just be reposed from Chatterjee and Rudra's schematic drawing (which is now known to be wrong in various ways thanks to the description). A complete skull is illustrated and listed for Rajasaurus, but while there is a cast that's often photographed, only a braincase is present according to the description. For those curious why Aucasaurus is sunk into Abelisaurus- "the only reason this does not appear to be a juvenile A. comahuensis is that fusion of skeletal elements suggests it is an adult." It should be noted Paul has an odd phylogeny where ceratosaurids and elaphrosaurs are closer to tetanurines than abelisauroids are. The seemingly rigorous Elaphrosaurus skeletal incorrectly has a complete vertebral column, all chevrons (only one is preserved) and complete pes, but doesn't include the scapulocoracoid or metacarpals.
Poekilopleuron bucklandii being the same genus and/or species as Megalosaurus bucklandii might have been a viable idea back in 1988, but not now that both have been redescribed. Another odd aspect to Paul's phylogeny is that Piatnitzkysaurus, Condorraptor, Magnosaurus, Eustreptospondylus (as Streptospondylus) and Afrovenator are avetheropods. The rationale for sinking Eustreptospondylus- "Eustreptospondylus oxoniensis is tentatively placed in Streptospondylus altdorfensis." Eustreptospondylus' skeletal is odd in lacking most of the skull besides the premaxilla, maxilla and quadrate, but a lot of what is shown is not preserved (ribs, most caudal vertebrae, chevrons, etc.).
Sinraptor hepingensis is synonymized with Yangchuanosaurus shangyouensis, but S. dongi (with a humerus and coracoid in its rigorous skeletal) is kept separate. Monolophosaurus and Guanlong are both sinraptorids, which has never been supported to my knowledge. Paul retains the old short snout vs. long snout Allosaurus dichotomy which Chure has showed is untrue. For Neovenator, he states "That researchers have disagreed whether this is a basal tyrannosauroid or an allosauroid suggests these groups may be more closely related than thought." But whoever proposed Neovenator is a tyrannosauroid?
For Coelurosauria, Paul states "The validity of the group is not certain." But who has ever had a theropod phylogeny without it? While I do applaud Paul's indicating when taxa are based on juvenile specimens, he's incorrect in calling the heavily fused Bagaraatan type a juvenile and the young Raptorex type an adult. On the other hand, I was happy to see him call both Alioramus species juveniles and probably synonymous. One new combination missing in my taxonomy post is "Appalachiosaurus (or Albertosaurus) montgomeriensis." Using Carr's data, that seems fine as long as Bistahieversor is Albertosaurus too.
Paul lumps all American ornithomimids into Struthiomimus, but says Struthiomimus? sedens "includes Ornithomimus velox, which is based on entirely inadequate remains." GAK!!! Impossible. Ornithomimus and the species velox have priority over Struthiomimus and sedens. If Ornithomimus' syntypes are entirely inadequate (and they're not), it couldn't be assigned to the same species as sedens.
The rigorous Ornitholestes skeletal lacks any forearm or manus material (even though the famous manus has been reassigned to Tanycolagreus, the holotype has manus material as well). Scansoriopteryx is used instead of Epidendrosaurus, which is nice. Yet the taxon is not placed with Epidexipteryx, as the latter is assigned to Oviraptorosauria instead. Wherever the taxa belong, their morphology is so similar that they may even be synonymous. If Paul would have used all the manual phalanges in Epidexipteryx, he would have found it impossible to restore with normal hands.
Shanag is sunk into Sinornithosaurus because "Too little is known to distinguish this from Sinornithosaurus." Tsaagan and Graciliraptor don't even get that much explanation. Deinonychus' skeletal is oddly incomplete (no scapula, humerus, ilium, pubis, femur, tibia or fibula), which I'm assuming is due to Paul's statement Lower Cloverly remains "are probably one or more different taxa."
The oviraptorosaurs are all given bifurcated tail fans, but Gatesy (2001) showed this was an illusion in Caudipteryx. Both Epidexipteryx and omnivoropterygids are placed in Oviraptorosauria, which has never been supported by an analysis, but I do like that Paul uses Omnivoropterygidae instead of Sapeornithidae. The caenagnathid taxonomy is highly confused. Using Paul's names, it consists of- Caenagnathus collinsi (only the type mandible), Caenagnathus? sp. (the two undescribed Triebold skeletons), Chirostenotes pergracilis (said to possibly include elegans), Chirostenotes? sp. (the specimen described in Sues, 1997), and Elmisaurus (or Chirostenotes) rarus. Where to begin? The Triebold skeletons combine Caenagnathus jaws with Chirostenotes postcrania, so there's no reason to keep the genera separate, let alone refer the Triebold material to one genus or the other. elegans is more similar to Elmisaurus despite the undefended assertions of some recent papers (Sues, 1997; Maryanska et al., 2002; Osmolska et al., 2004). The Horseshoe Canyon specimen described by Sues has never been suggested to belong to a distinct taxon in the literature, and was seemingly just separated based on stratigraphy. Shanyangosaurus is listed as a caenagnathid, which I find amusing since I suggested it was an oviraptorosaur back in 2000, that was also followed by Holtz et al. (2004). Ironically, I no longer think my analysis was sufficient to place it anywhere specific within Maniraptora.
Oviraptorids themselves were lumped a lot. For Citipati osmolskae, Paul says "It is probable that crestless Khaan mckennai is the juvenile form of this species." And for "Conchoraptor (or Citipati) gracilis", he says "It is probable that all specimens from this formation are juveniles and adults of one species whose taxonomy is complicated because the genus portion of the original name Ingenia yanshini turned out to be preoccupied by an invertebrate." But as I noted before, just because Ingenia is preoccupied doesn't mean yanshini wouldn't still be the species name. Nor can Conchoraptor gracilis ever be Citipati gracilis, since Conchoraptor has priority over Citipati. His illustration for this conglomerate of taxa is basically "Ingenia" but with that privately owned skull with the very tall pointed crest. I do like that Paul illustrates the internal nostrils on the side of the ventrally projected palate in oviraptorids.
The reconstruction of Beipiaosaurus uses the new anterior skeleton and features a silly-looking vaguely stegosaur-like skull with a pointy snout. Contra to Paul who thinks Nothronychus graffami (mistyped grafmani) might be synonymous with N. mckinleyi, I'm doubtful they're even congeneric.
Next up, sauropodomorphs...
Thursday, October 14, 2010
"The Princeton Field Guide to Dinosaurs" - The Ornithischians
Finishing up the review series is this post on ornithischians. As with sauropodomorphs, these aren't my speciality, so I don't have educated opinions on most of the issues nor do I always know exactly what the latest consensus is. Honestly, the same kinds of problems are present in this section as the previous one. I think I've figured out Paul's splitter/lumper methodology though. If a taxon is similar to another, but from a different horizon, it's a different species! Doesn't matter if anyone's actually tried to name a distinct taxon from there yet, or if there are actually any differences reported in the literature. If a taxon is from the same horizon as another similar one, they're synonymous! Ignore priority and use the name of the most complete specimen for the taxon. If a species forms a clade with another, they're congeneric! With these three easy steps, you too can lump and split the GSP way. ;)
As with the other sections, there are many excellent reconstructions. My favorites are Scutellosaurus, Gigantspinosaurus, Saichania, Pinacosaurus, Ankylosaurus, Edmontonia, Archaeoceratops, Prenoceratops, Montanaceratops, Talenkauen, Gasparinisaura, Muttaburrasaurus, Probactrosaurus, Tethyshadros, and the many derived hadrosaurs. It's nice to see the ankylosaurs and hadrosaurs reconstructed, since usually people only bother with their skulls.
Like theropods, thyreophorans unjustly suffer from the statement "absence from Antarctica probably reflects lack of sufficient sampling." Despite the fact Antarctopelta is known AND included in the book. Chungkingosaurus and Chialingosaurus are said to probably be juvenile Tuojiangosaurus, but the former is a diagnostic huayangosaurid (Maidment and Wei, 2006) and the latter has priority over Tuojiangosaurus. Upper Tendaguru Kentrosaurus remains "probably belong to a different taxon" while Stegosaurus longispinus "probably is a more basal stegosaurid." These may be true, I don't know. Amusingly, Wuerhosaurus "is not a species of Stegosaurus as has been suggested." I'm not sure why Paul's lumpometer fails here. For "Hesperosaurus (or Stegosaurus) mjosi", "Lack of limbs hinders assessing whether this is a Stegosaurus as some reseachers have concluded." Because Stegosaurus is apomorphy-defined using limb characters?
Dracopelta, Shamosaurus, Gobisaurus, Stegopelta, Niobrarasaurus and Antarctopelta are listed as "polacanthians." Good ol' nonexistent Polacanthia... I'm unaware of these taxa even being referred to Polacanthidae. Pinacosaurus mephistocephalus is listed as a synonym of P. grangeri and Struthiosaurus languedocensis "may be the adult" of S. austriacus. Again, are these plausible? I don't know. But claiming Pawpawsaurus "probably includes Texasetes pleurohalio" is certainly incorrect, as Texasetes has priority. "Euoplocephalus tutus" is placed in quote marks, said to have an inadequate holotype and said to possibly consists of multiple taxa. Horseshoe Canyon specimens are assigned to ""Euoplocephalus" unnamed species?" though, presumably because they're from a different formation.
Butler will be surprised to hear Heterodontosaurus "probably includes the smaller, tuskless Abrictosaurus consors as well as Lycorhinus angustidens."
Homalocephalids are said to probably be immature pachycephalosaurids or females, which leads to "Goyocephale (or Stegoceras) lattimorei" and "Prenocephale (or Stegoceras) prenes" with Homalocephale "probably an immature P. prenes." There's also "Tylocephale (or Stegoceras) gilmorei." Even if he's right about homalocephalids, none of the Asian taxa are especially close to Stegoceras. Of course Paul's Stegoceras is a huge para/polyphyletic mass including every non-Pachycephalosaurus North American taxon at least, since Stegoceras? brevis "may include Colepiocephale lambei", and Stegoceras validum "may include Hansuessia sternbergi." Dracorex and Stygimoloch are probably juvenile Pachycephalosaurus "in which case the spikes are a sexual characteristic, or there may be two species, the other being P. spinifer." But what about the spikes being resorbed?
The only new non-theropod taxonomic name proposed in the book is Paxceratopsia for psittacosaurs and neoceratopsians, but not chaoyangosaurs. Psittacosaurus meileyingensis "probably includes P. ordosensis", Udanoceratops "may include Bainoceratops efremovi" and Gobiceratops "may be a juvenile" Bagaceratops. Again, I'm not sure if these are plausible. I was disappointed to see all non-ceratopsid neoceratopsians called protoceratopsids. Cerasinops is listed twice in the book, with identical entries at least. For ceratopsids, Paul has the odd division between centrosaurines, chasmosaurines AND ceratopsines. Err.... Paul includes only Triceratops and Avaceratops in Ceratopsinae and says "The existence of this group is not certain." Well, since it's never been recovered in an analysis and there's no reason Ceratops itself is close to either genus, I suppose that's true. Paul's ceratopsids are lumped like there's no tomorrow. There's "Albertoceratops (=Diabloceratops) eatoni". All other centrosaurines are Centrosaurus, so we get Centrosaurus (=Styracosaurus) albertensis, C. (=Styracosaurus) ovatus, C. (=Einosaurus[sic]) procurvicornis, C. (=Achelousaurus) horneri, C. (=Pachyrhinosaurus) lakustai, and C. (=Pachyrhinosaurus) canadensis. But Centrosaurus nasicornis and C. apertus are separate, no doubt because they're from different levels of the Dinosaur Park. Not only is such lumping pointless, IF it were true, Monoclonius would be the proper genus since crassus is definitely somewhere in that clade. For chasmosaurines, we get Chasmosaurus (Pentaceratops = Agujaceratops) mariscalensis and Chasmosaurus (Pentaceratops) sternbergi. Which makes both Chasmosaurus and the supposed subgenus Pentaceratops para/polyphyletic. And of course Triceratops is lumped, with Triceratops (=Eotriceratops) xerinsularis, and Nedoceratops (incorrectly listed as Diceratops) a synonym of T. horridus.
Moving on to ornithopods, Hexinlusaurus "is probably immature example of" Agilisaurus louderbacki. Even though the former is closer to ornithopods in Butler's tree. Then we have "Agilisaurus? unnamed species" which was "named Yandusaurus hongheensis based on inadequate remains." Not only is Yandusaurus closer to ornithopods than Agilisaurus, but Yandusaurus has priority over Agilisaurus AND how can you have an unnamed species that used to be a named species?! More predictably bad taxonomy- Othnielosaurus consors was "once Othnielia rex." More like Othnielia isn't necessarily Othnielosaurus. Anabisetia, Gasparinisaura, Talenkauen, Thescelosaurus and Parksosaurus are all listed as hypsilophodonts, but are iguanodonts. Iguanodonts also get the old "absence from Antarctica probably reflects lack of sufficient sampling" treatment, but there's a hadrosaur from there (Case et al., 2000). The Tenontosaurus dossi cranial reconstruction doesn't have premaxillary teeth. For rhabdodont lumping, Rhabdodon (=Zalmoxes) robustus "probably includes Z. shqiperorum." But then for horizon-based splitting, "Dryosaurus unnamed species" (for Utah Middle Morrison remains) is "usually placed in D. altus but probably is a different species than the latter dryosaur, and differing genera cannot be ruled out." The placement of taxa in Paul's iguanodont grades seems problematic, with e.g. Planicoxa being a dryosaur. I was amused that Paul's own taxon Dollodon bampingi is misspelled "bambingi" every time.
Finally, there's the lumptastic hadosaurs. It honestly looks like Paul just used a twenty-year old classification and applied his three lumping/splitting steps. Bactrosaurus "probably includes Gilmoreosaurus mongoliensis." We get Saurolophus (=Lophorthothon[sic]) atopus, Saurolophus (=Prosaurolophus) blackfeetensis, and Saurolophus (=Prosaurolophus) maximus. Lophorhothon isn't even a hadrosaurid, while blackfeetensis is a synonym of maximus, but silly me it's from a different formation. Maisaura (or Brachylophosaurus) peeblesorum "may be a subgenus of Brachylophosaurus", which is just meaningless. There's Kritosaurus (or Gryposaurus) latidens, notabilis, incurvimanus, and monumentensis and Kritosaurus (or Anasazisaurus) horneri. Last I heard, horneri was a synonym of navajovius, incurvimanus was a synonym of notabilis, and you'd need to put Secernosaurus in Kritosaurus if you put Gryposaurus there. Most sadly, we have Aralosaurus (or Kritosaurus) tubiferus, despite the fact Aralosaurus is a lambeosaurine. Pararhabdodon "probably includes Koutalisaurus", which agrees with Prieto-Marquez. Parasaurolophus walkeri and "P. tubicen are not distinctive from one another, and short crested New Mexican P. cyrtocristatus may be a female or subadult of this species." I'm not sure about the evidence for that. Olorotitan "may be the same genus or species as Amurosaurus riabinini", which is untrue as they're not closely related within Lambeosaurinae. We get both Nipponosaurus (or Hypacrosaurus) sachaliensis and Barsboldia (or Hypacrosaurus) sicinskii, though the latter is a saurolophine. In fact, all the helmet-crested lambeosaurines get placed in one genus. There's Hypacrosaurus (=Velafrons) coahuilensis, Hypacrosaurus (=Corythosaurus) casuarius and intermedius, Hypacrosaurus (=Lambeosaurus) clavintialis, lambei and mangicristatus, and Hypacrosaurus? laticaudus. Again, I didn't think clavintialis was valid, while you'd need to put Amurosaurus and Sahaliyania in Hypacrosaurus too if you're lumping like that.
And that's it. Be sure to check out Jaime Headden's review and future commentary too.
As with the other sections, there are many excellent reconstructions. My favorites are Scutellosaurus, Gigantspinosaurus, Saichania, Pinacosaurus, Ankylosaurus, Edmontonia, Archaeoceratops, Prenoceratops, Montanaceratops, Talenkauen, Gasparinisaura, Muttaburrasaurus, Probactrosaurus, Tethyshadros, and the many derived hadrosaurs. It's nice to see the ankylosaurs and hadrosaurs reconstructed, since usually people only bother with their skulls.
Like theropods, thyreophorans unjustly suffer from the statement "absence from Antarctica probably reflects lack of sufficient sampling." Despite the fact Antarctopelta is known AND included in the book. Chungkingosaurus and Chialingosaurus are said to probably be juvenile Tuojiangosaurus, but the former is a diagnostic huayangosaurid (Maidment and Wei, 2006) and the latter has priority over Tuojiangosaurus. Upper Tendaguru Kentrosaurus remains "probably belong to a different taxon" while Stegosaurus longispinus "probably is a more basal stegosaurid." These may be true, I don't know. Amusingly, Wuerhosaurus "is not a species of Stegosaurus as has been suggested." I'm not sure why Paul's lumpometer fails here. For "Hesperosaurus (or Stegosaurus) mjosi", "Lack of limbs hinders assessing whether this is a Stegosaurus as some reseachers have concluded." Because Stegosaurus is apomorphy-defined using limb characters?
Dracopelta, Shamosaurus, Gobisaurus, Stegopelta, Niobrarasaurus and Antarctopelta are listed as "polacanthians." Good ol' nonexistent Polacanthia... I'm unaware of these taxa even being referred to Polacanthidae. Pinacosaurus mephistocephalus is listed as a synonym of P. grangeri and Struthiosaurus languedocensis "may be the adult" of S. austriacus. Again, are these plausible? I don't know. But claiming Pawpawsaurus "probably includes Texasetes pleurohalio" is certainly incorrect, as Texasetes has priority. "Euoplocephalus tutus" is placed in quote marks, said to have an inadequate holotype and said to possibly consists of multiple taxa. Horseshoe Canyon specimens are assigned to ""Euoplocephalus" unnamed species?" though, presumably because they're from a different formation.
Butler will be surprised to hear Heterodontosaurus "probably includes the smaller, tuskless Abrictosaurus consors as well as Lycorhinus angustidens."
Homalocephalids are said to probably be immature pachycephalosaurids or females, which leads to "Goyocephale (or Stegoceras) lattimorei" and "Prenocephale (or Stegoceras) prenes" with Homalocephale "probably an immature P. prenes." There's also "Tylocephale (or Stegoceras) gilmorei." Even if he's right about homalocephalids, none of the Asian taxa are especially close to Stegoceras. Of course Paul's Stegoceras is a huge para/polyphyletic mass including every non-Pachycephalosaurus North American taxon at least, since Stegoceras? brevis "may include Colepiocephale lambei", and Stegoceras validum "may include Hansuessia sternbergi." Dracorex and Stygimoloch are probably juvenile Pachycephalosaurus "in which case the spikes are a sexual characteristic, or there may be two species, the other being P. spinifer." But what about the spikes being resorbed?
The only new non-theropod taxonomic name proposed in the book is Paxceratopsia for psittacosaurs and neoceratopsians, but not chaoyangosaurs. Psittacosaurus meileyingensis "probably includes P. ordosensis", Udanoceratops "may include Bainoceratops efremovi" and Gobiceratops "may be a juvenile" Bagaceratops. Again, I'm not sure if these are plausible. I was disappointed to see all non-ceratopsid neoceratopsians called protoceratopsids. Cerasinops is listed twice in the book, with identical entries at least. For ceratopsids, Paul has the odd division between centrosaurines, chasmosaurines AND ceratopsines. Err.... Paul includes only Triceratops and Avaceratops in Ceratopsinae and says "The existence of this group is not certain." Well, since it's never been recovered in an analysis and there's no reason Ceratops itself is close to either genus, I suppose that's true. Paul's ceratopsids are lumped like there's no tomorrow. There's "Albertoceratops (=Diabloceratops) eatoni". All other centrosaurines are Centrosaurus, so we get Centrosaurus (=Styracosaurus) albertensis, C. (=Styracosaurus) ovatus, C. (=Einosaurus[sic]) procurvicornis, C. (=Achelousaurus) horneri, C. (=Pachyrhinosaurus) lakustai, and C. (=Pachyrhinosaurus) canadensis. But Centrosaurus nasicornis and C. apertus are separate, no doubt because they're from different levels of the Dinosaur Park. Not only is such lumping pointless, IF it were true, Monoclonius would be the proper genus since crassus is definitely somewhere in that clade. For chasmosaurines, we get Chasmosaurus (Pentaceratops = Agujaceratops) mariscalensis and Chasmosaurus (Pentaceratops) sternbergi. Which makes both Chasmosaurus and the supposed subgenus Pentaceratops para/polyphyletic. And of course Triceratops is lumped, with Triceratops (=Eotriceratops) xerinsularis, and Nedoceratops (incorrectly listed as Diceratops) a synonym of T. horridus.
Moving on to ornithopods, Hexinlusaurus "is probably immature example of" Agilisaurus louderbacki. Even though the former is closer to ornithopods in Butler's tree. Then we have "Agilisaurus? unnamed species" which was "named Yandusaurus hongheensis based on inadequate remains." Not only is Yandusaurus closer to ornithopods than Agilisaurus, but Yandusaurus has priority over Agilisaurus AND how can you have an unnamed species that used to be a named species?! More predictably bad taxonomy- Othnielosaurus consors was "once Othnielia rex." More like Othnielia isn't necessarily Othnielosaurus. Anabisetia, Gasparinisaura, Talenkauen, Thescelosaurus and Parksosaurus are all listed as hypsilophodonts, but are iguanodonts. Iguanodonts also get the old "absence from Antarctica probably reflects lack of sufficient sampling" treatment, but there's a hadrosaur from there (Case et al., 2000). The Tenontosaurus dossi cranial reconstruction doesn't have premaxillary teeth. For rhabdodont lumping, Rhabdodon (=Zalmoxes) robustus "probably includes Z. shqiperorum." But then for horizon-based splitting, "Dryosaurus unnamed species" (for Utah Middle Morrison remains) is "usually placed in D. altus but probably is a different species than the latter dryosaur, and differing genera cannot be ruled out." The placement of taxa in Paul's iguanodont grades seems problematic, with e.g. Planicoxa being a dryosaur. I was amused that Paul's own taxon Dollodon bampingi is misspelled "bambingi" every time.
Finally, there's the lumptastic hadosaurs. It honestly looks like Paul just used a twenty-year old classification and applied his three lumping/splitting steps. Bactrosaurus "probably includes Gilmoreosaurus mongoliensis." We get Saurolophus (=Lophorthothon[sic]) atopus, Saurolophus (=Prosaurolophus) blackfeetensis, and Saurolophus (=Prosaurolophus) maximus. Lophorhothon isn't even a hadrosaurid, while blackfeetensis is a synonym of maximus, but silly me it's from a different formation. Maisaura (or Brachylophosaurus) peeblesorum "may be a subgenus of Brachylophosaurus", which is just meaningless. There's Kritosaurus (or Gryposaurus) latidens, notabilis, incurvimanus, and monumentensis and Kritosaurus (or Anasazisaurus) horneri. Last I heard, horneri was a synonym of navajovius, incurvimanus was a synonym of notabilis, and you'd need to put Secernosaurus in Kritosaurus if you put Gryposaurus there. Most sadly, we have Aralosaurus (or Kritosaurus) tubiferus, despite the fact Aralosaurus is a lambeosaurine. Pararhabdodon "probably includes Koutalisaurus", which agrees with Prieto-Marquez. Parasaurolophus walkeri and "P. tubicen are not distinctive from one another, and short crested New Mexican P. cyrtocristatus may be a female or subadult of this species." I'm not sure about the evidence for that. Olorotitan "may be the same genus or species as Amurosaurus riabinini", which is untrue as they're not closely related within Lambeosaurinae. We get both Nipponosaurus (or Hypacrosaurus) sachaliensis and Barsboldia (or Hypacrosaurus) sicinskii, though the latter is a saurolophine. In fact, all the helmet-crested lambeosaurines get placed in one genus. There's Hypacrosaurus (=Velafrons) coahuilensis, Hypacrosaurus (=Corythosaurus) casuarius and intermedius, Hypacrosaurus (=Lambeosaurus) clavintialis, lambei and mangicristatus, and Hypacrosaurus? laticaudus. Again, I didn't think clavintialis was valid, while you'd need to put Amurosaurus and Sahaliyania in Hypacrosaurus too if you're lumping like that.
And that's it. Be sure to check out Jaime Headden's review and future commentary too.
Wednesday, May 16, 2018
Testing alternative stem bird topologies in Cau, 2018
In the comments to my last post describing Cau's (2018) new paper detailing the acquisition of characters on the line to Aves, reader AOF requested a post similar to what I did six years ago with the Carrano et al. (2012) tetanurine analysis. Namely, testing alternative topologies using constraint analyses to see how many more steps they would require. I think these kinds of things can be illuminating. I've often said that we shouldn't think of a new cladogram as just 'the best new hypothesis', but rather check individual components of the tree to see how likely or unlikely they are to be correct. Cau's 2018 matrix has a reduced taxon sample, which could easily change the number of steps compared to a complete sample. On the other hand, I think Andrea tries to include all proposed characters in his MegaMatrix, which could make this a more honest measure of comparative topology length than most studies. I'm not sure which variable overrides the other. Then we have score correctness, which I've never checked in a Cau matrix, so I'm taking that at face value.
Andrea sent me his NEXUS file, but whereas the paper reports 3072 MPTs of 6790 steps, I found 10872 MPTs of that length. Eoraptor and Buriolestes aren't always sauropodomorphs, Pisanosaurus is sometimes an ornithischian, Asilisaurus, Silesaurus and Sacisaurus are an unresolved trichotomy, Enantiornithes can be paraphyletic with Zhongjianornis among them, and Fake Ornithuromorpha is less resolved, as Patagopteryx and Apsaravis can be outside Hongshanornis+Aves, Archaeornithura can be a songlingornithid, etc.. I think Andrea's philosophy would be that these things vary with taxon inclusion, so aren't a definite part of his data. The absence of any included spinosaurids, carcharodontosaurines, parvicursorines or Avimimus unfortunately makes some weird 80s and 90s hypotheses untestable. After six more years of experience, I've added a new category "less likely" because I think that factors like scoring accuracy and taxon inclusion can have a larger influence. As I said in the 2012 post, the corrected TWG matrix needed 15 more steps to get a monophyletic Deinonychosauria which is the most common outcome for TWG matrices today. I'll say the Lori matrix recovers at least one hypothesis found to be "unlikely" here, so even that's not the kiss of death.
Basically ambiguous
0 steps- Maniraptoromorph Compsognathus.
0 steps- Megaraptoran Gualicho.
1 step- Ceratosaurus closer to abelisauroids than Elaphrosaurus.
1 step- Megalosauroid piatnitzkysaurids.
1 step- Coelurosaurian Zuolong. Ends up as a basal maniraptoromorph between Coelurus and Ornitholestes.
1 step- Coelurid Aorun, as in its original description. It moves to Maniraptoromorpha with Coelurus.
1 step- Coelurid Tanycolagreus, as in its original description. Coelurus moves into Tyrannosauroidea with Tanycolagreus.
1 step- Compsognathid Sinosauropteryx and/or Sinocalliopteryx.
1 step- Tyrannosauroid Sinocalliopteryx or Coelurus.
1 step- Anchiornithid or archaeopterygid Xiaotingia.
1 step- Scansoriopterygids closer to Aves than Archaeopteryx.
1 step- Sapeornis closer to Aves than Confuciusornis.
1 step- Zhongjianornis sister to Pygostylia, as in its original description.
1 step- Ichthyornis closer to Aves than Hesperornis, the consensus until the recent cranial redescription of Ichthyornis.
2 steps- Theropodan Eodromaeus.
2 steps- Chilesaurus just outside Avepoda, which was my best guess back in 2015 considering the results of its original misscored matrices and my subjective feelings of what would plausibly reverse.
2 steps- Ceratosaurian Gualicho. It has an uncertain placement within the clade, though is excluded from Abelisauria.
2 steps- Megaraptora as coelurosaurs just outside of Tyrannoraptora. This was my result back in 2010 after adding Benson's Neovenatoridae data to my theropod supermatrix (since superseded by the Lori analysis). Bicentenaria is at this level too, while Guanlong and Tanycolagreus become maniraptoromorphs.
2 steps- Maniraptoran Ornitholestes.
2 steps- Hongshanornithid Parahongshanornis, as in its original description.
Quite likely to be true
3 steps- Saurischia. Herrerasaurs and Eodromaeus are theropods. Note that while some of these constraints were tested in the Ornithoscelida paper, the studies differ in both taxonomic content and characters used, so that MegaMatrix results don't necessarily correlate with Ornithoscelida paper results and should not be seen as scooping anything we find.
3 steps- Ornithischian Daemonosaurus. Chilesaurus is sister to Averostra.
3 steps- Theropodan Herrerasaurus/Tawa/Daemonosaurus. These each take three steps more, and other herrerasaurs follow when one is constrained.
3 steps- Dilophosaurid Liliensternus, as in Paul (1988).
3 steps- Ceratosauria sensu lato, combining Neoceratosauria and Coelophysoidea. Chilesaurus is the most basal theropod, Elaphrosaurus plus Limusaurus are the basal neoceratosaurs, and Gualicho is the most basal tetanurine.
3 steps- Eustreptospondylus and/or Megalosaurus outside Avetheropoda. If one is constrained, the other follows.
3 steps- Megaraptoran Eotyrannus, as in Novas et al. (2013).
3 steps- Maniraptoran Coelurus.
3 steps- Troodontid Aurornis, Anchiornis and/or Xiaotingia.
3 steps- Chongmingia sister to Ornithothoraces, as in p2 of its original description.
4 steps- Ornithischian silesaurids. Lewisuchus is outside Dinosauria, Saurischia exists, and Asilisaurus and Pisanosaurus form a silesaur grade to either side of Silesauridae.
4 steps- Phytodinosauria. Eoraptor and Buriolestes are sister to Dinosauria, while herrerasaurs and Eodromaeus are theropods.
4 steps- Ornithischian Chilesaurus. Ornithoscelida occurs.
4 steps- Theropodan Eoraptor. Buriolestes, herrerasaurs and Eodromaeus also theropods.
4 steps- Abelisaurid Eoabelisaurus, as in its original description.
4 steps- Metriacanthosaurids outside Allosauria (Allosaurus plus Carcharodontosaurus). Acrocanthosaurus joins Neovenator, so this also covers carcharodontosaurid Neovenator.
4 steps- Tyrannosauroid Compsognathus, as in Olshevsky (1991). Surprised this one is so parsimonious. A Compsognathidae with Aorun, Bicentenaria and Sinosauropteryx are the basalmost tyrannosauroids, with Sinocalliopteryx, Coeluridae including Tanycolagreus and Guanlong successively closer to core tyrannosauroids.
4 steps- Maniraptoromorph Tanycolagreus and/or Guanlong.
4 steps- Ornithomimosaurian Gualicho. Tested due to Rauhut (2003) finding the very similar Deltadromeus in this position. Note that ornithomimosaurian Elaphrosaurus is 36 steps longer, so the cases aren't that similar.
4 steps- Therizinosaurian Jianchangosaurus. Still outside Falcarius plus Beipiaosaurus, and Cau said in a comment to the last post Jianchangosaurus was still an alvarezsauroid even after adding Erlikosaurus and Shuvuuia. I'm not revealing much by saying the Lori analysis finds Jianchangosaurus to be a therizinosaur between Falcarius and Beipiaosaurus as in its original description. Seems fishy...
4 steps- Archaeopterygid Jinfengopteryx, as in its original description.
4 steps- Archaeopterygid Anchiornis.
4 steps- Oviraptorosaurian scansoriopterygids. They have an uncertain position within the clade, and therizinosaurs are still sister to oviraptorosaurs.
5 steps- Dilophosaurus/Cryolophosaurus closer to Averostra than Coelophysis.
5 steps- Non-avetheropod Compsognathus, as in Novas (1992). Very surprised this is so easy to get. It's even more extreme than Novas' version, where Compsognathus was at least closer to avetheropods (his Tetanurae) than Piatnitzkysaurus and Eustreptospondylus, because in the constrained trees Carnosauria still has the same content as Cau's MPTs. Sinosauropteryx joins it.
5 steps- Maniraptoromorph Eotyrannus. I'm surprised by this, since I figured the result in other matrices was due to a lack of tyrannosauroid characters, which I think are all in the MegaMatrix.
5 steps- Non-tyrannoraptoran Coelurus, as in Paul (1988).
5 steps- Avemetatarsalian alvarezsauroids, as in Sereno (1999). Jianchangosaurus is still a basal alvarezsauroid.
5 steps- Haplocheirus compsognathid/coelurid grade, as in Alifanov and Saveliev (2011). Wasn't there some analysis that recovered it here too? I just constrained it to be outside Maniraptoriformes (including alvarezsaurids).
5 steps- Non-pennaraptoran therizinosaurs, which fall out sister to Pennaraptora like the current consensus.
5 steps- Chongmingia a basal ornithurine (sensu Gauthier) outside Shenzhouraptor and Pygostylia, as in p1 of its original description. The Lori analysis recovers it in a different position than p1, p2 or Cau's analysis.
Less likely
6 steps- Non-eusaurischian saurischian Eoraptor. Buriolestes follows, but herrerasaurs and Eodromaeus are theropods.
6 steps- Theropodan Guaibasaurus. Non-dinosaurian Eoraptor and Buriolestes, and this recovers Phytodinosauria.
6 steps- Eustreptospondylus closer to Neotetanurae than Megalosaurus, as in Holtz (2000). I'm actually surprised this is so unlikely.
6 steps- Carnosaurian Sinosauropteryx, as in Longrich (2002). Though Longrich's phylogeny was a bit different in having megalosaurids and metriacanthosaurids outside Avetheropoda.
6 steps- Ornithomimosaurian Haplocheirus, as in the Bayesian analyses of Cau and Lee and Worthy (2011).
6 steps- Arctometatarsalian therizinosaurs, as in Sereno (1999).
6 steps- Shenzhouraptor closer to Aves than Sapeornis.
7 steps- Sauropodomorph Staurikosaurus but not Herrerasaurus, as in pachypodosaur Staurikosaurus of Kischlat (2000).
7 steps- Megalosauroid Monolophosaurus. Megalosauroidea remains in Carnosauria.
7 steps- Coelurosaurian Neovenator. Not sure if this has been suggested in print before, but I noticed quite a few coelurosaur-like characters when scoring Neovenator for the Lori matrix. It forms the most basal coelurosaur clade with Aorun and Gualicho.
7 steps- Maniraptoran Compsognathus.
7 steps- Paravian alvarezsaurids, though note the lack of parvicursorines probably affects these numbers. They (including Jianchangosaurus and Haplocheirus) emerge as the most basal paravians.
7 steps- Basal paravian Anchiornis, Aurornis, scansoriopterygids, Serikornis and/or Xiaotingia.
7 steps- Archaeopterygid Rahonavis, as in Forster et al. (1998).
7 steps- Fake-Ornithuromorphan Confuciusornis, as in Kurochkin (2006). I really thought this would be more difficult to achieve than enantiornithine Confuciusornis (below).
8 steps- Non-eusaurischian saurischian Herrerasaurus. Eodromaeus and sometimes Eoraptor become herrerasaurs and Buriolestes is one node more stemward.
8 steps- Tetanurine Cryolophosaurus, as in Carrano et al. (2002). Dilophosaurus stays in Coelophysoidea.
8 steps- Ceratosaurian megalosaurids, as in Britt (1991). Chilesaurus falls out in a polytomy with megalosaurids and other ceratosaurs.
8 steps- Megalosauroid piatnitzkysaurids, with Megalosauroidea outside Avetheropoda. Since this is the Carrano et al. consensus, I thought it would take less steps.
8 steps- Monolophosaurus sister to Avetheropoda, as in Smith et al. (2007). Megalosaurids and piatnitzkysaurids fall out as more basal tetanurines.
8 steps- Arctometatarsalian tyrannosauroids, AKA Tyrannosaurus closer to Ornithomimus than to birds as in Holtz (1994). I'm very surprised this is so parsimonious. Coelurus and Bicentenaria join Tyrannosauroidea, but Gualicho leaves to be a ceratosaur.
8 steps- Maniraptoran tyrannosauroids, as in Sereno (1999). This is accomplished more by moving ornithomimosaurs (including Gualicho) stemward to be the most basal coelurosaurs except for Zuolong.
Somewhat possible
9 steps- Classic late 80s to early 90s topology where Staurikosaurus is sister to Herrerasaurus plus Dinosauria. Tawa plus Daemonosaurus are closer to dinosaurs than both, while Sanjuansaurus follows Herrerasaurus.
9 steps- Piatnitzkysaurus outside Orionides, as in Rauhut (2003). Condorraptor follows Piatnitzkysaurus, and megalosauroids fall outside Avetheropoda. Surprised this is so high.
9 steps- Carnosaurian Tyrannosaurus, which brings megaraptorans, Gualicho and Bicentenaria to form the sister group of Allosauroidea (including Monolophosaurus). I bet this is more parsimonious than most readers would assume given published topologies over the past two decades.
9 steps- Avialan Caudipteryx, as in its original description. The rest of Oviraptorosauria follows it, though troodontids are still closer to Aves.
9 steps- Avialan Microraptor, as in Agnolin and Novas (2013). Weirdly becomes the most basal troodontid, with that family closer to Aves than scansoriopterygids and anchiornithids.
9 steps- Avialan Unenlagia, as in its original description and Agnolin and Novas (2013). Halszkaraptorines are unenlagiids, which are outside the Troodontidae plus Ornithes clade.
9 steps- Deinonychosauria. Scansoriopterygids are oviraptorosaurs, while Jinfengopteryx and anchiornithids are avialans.
9 steps- Archaeopterygidae sister to Troodontidae. Anchiornithines fall out as archaeopterygids.
10 steps- Monolophosaurus outside Orionides, as in Carrano et al. (2002). Megalosaurids and piatnitzkysaurids form successively closer outgroups to Avetheropoda.
10 steps- Fukuivenator excluded from Alvarezsauridae plus Therizinosauria plus Pennaraptora as in its original description. It emerges as the sister to other maniraptorans.
10 steps- Eumaniraptora excluding troodontids as in Agnolin and Novas (2013). Scansoriopterygids are oviraptorosaurs.
10 steps- Dromaeosaurid Xiaotingia, as in Senter et al. (2012). Falls out in Microraptoria.
10 steps- Dromaeosaurid Balaur, as in its original description. Falls out sister to Unenalagiinae plus Halszkaraptorinae.
11 steps- Tyrannosauroid Acrocanthosaurus, as in Bakker et al. (1988). Tyrannosauroids become carnosaurs, with Sinraptor, Acrocanthosaurus and Bicentenaria successively closer to the 'core tyrannosauroid' clade of Eotyrannus, Gualicho, megaraptorans and Tyrannosaurus. Tanycolagreus and Guanlong are now maniraptoromorphs.
11 steps- Alvarezsauroid Nqwebasaurus. Alvarezsauroids emerge sister to ornithomimosaurs, with Haplocheirus and Jianchangosaurus forming a basal [edit] arctometatarsalian clade.
11 steps- Mahakala outside Unenlagiinae plus Eudromaeosauria (Halszkaraptor follows), as in most TWG matrices (though Senter et al. 2012 recovered it sister to unenlagiines like Cau).
Unlikely
12 steps- Alvarezsauroid Chilesaurus, where it emerged in the Lori matrix back in 2015.
12 steps- Ornithuran (sensu Gauthier) oviraptorosaurs, as in Maryanska et al. (2002). Constraining Khaan to be closer to Meleagris than Archaeopteryx results in oviraptorosaurs (including scansoriopterygids) being the first clade to diverge from the avian stem after Archaeopteryx.
12 steps- Basal paravian Jinfengopteryx, as in Foth et al. (2014).
13 steps- Coelophysoid Elaphrosaurus, as in Paul (1988). Ceratosauria sensu lato forms, Elaphrosaurus is outside core coelophysoids and Limusaurus and sometimes Gualicho follow.
13 steps- Compsognathid Nqwebasaurus, as in Novas et al. (2013). Compsognathids (including Aorun) become ornithomimosaurs.
13 steps- Dromaeosaurid Rahonavis. Emerges in the unenalgiine plus halszkaraptorine clade.
14 steps- Neovenatorid megaraptorans, though this actually moves Neovenator out of Carnosauria into Tyrannosauroidea, so isn't that similar to Benson's topology.
14 steps- Enantiornithine Confuciusornis.
15 steps- Sauropodomorphan Chilesaurus, where it emerges as the most basal member.
15 steps- Carnosaurian Ceratosaurus, as in Currie (1995). Other ceratosaurs follow.
15 steps- Alvarezsaurids closer to Aves than dromaeosaurids or troodontids. Haplocheirus and Jianchangosaurus remain behind as ornithomimosaurs. Note the lack of parvicursorines probably affects this number.
15 steps- Archaeopterygid Unenlagia, as in Forster et al. (1998). Buitreraptor remains in Dromaeosauridae.
16 steps- Saurischian Marasuchus, as in Kischlat (2000). Ornithischian silesaurs result, and Lewisuchus sister to Eodromaeus plus avepods.
16 steps- Non-avetheropod Sinraptor as in Longrich (2002). Carnosauria becomes a grade, Acrocanthosaurus joins Neovenator, and Guanlong and Tanycolagreus become maniraptoromorphs.
18 steps- Basal paravian Archaeopteryx. Deinonychosauria forms, and anchiornithids and scansoriopterygids are further from Eumaniraptora.
19 steps- Coelophysoid ornithischians or ornithischians sister to Neotheropoda, as in Baron (2017). Chilesaurus is the most basal theropod.
19 steps- Basal deinonychosaur Archaeopteryx, as in Xu et al. (2011). Anchiornis, Aurornis and Serikornis are one node closer to Dromaeosauridae plus Troodontidae.
20 steps- Monolophosaurus sister to Guanlong, as in Carr (2006) who proposed they were an adult and juvenile of the same species. The pairing resolves as sister to Tyrannoraptora.
21 steps- Carnosaurian megaraptorans. Er, wow. The Carrano et al. consensus is blown out of the water. They don't even group with Neovenator, instead (including Gualicho and Bicentenaria) being in a trichotomy with megalosaurids and an Allosauroidea including piatnitzkysaurids.
I'm drawing the line here for plausibility
22 steps- Theropodan Marasuchus, as in Olshevsky (1991). Silesaurids, Eoraptor+Buriolestes and herrerasaurians are also theropods.
23 steps- Avialan therizinosaurs, as in Maryanska et al. (2002). One of the odder parts of the classic 'oviraptorosaurs are birds' analysis is that they recovered therizinosaurs as closer to birds than dromaeosaurids or troodontids, which was only briefly mentioned in the text, while they removed Troodontidae and Therizinosauria from their figured cladogram. Constraining this result leads to oviraptorosaurs being dragged along, and the whole of Caenagnathiformes is sister to taxa closer to Aves like scansoriopterygids, anchiornithids, Archaeopteryx, etc..
24 steps- 'Allosaur' Ornitholestes, as in Paul (1988). Although Paul includes Ornitholestes in his Allosauridae, he views that family as paraphyletic to tyrannosaurids and his figure 10-1 shows Allosaurus closer to tyrannosaurids than Ornitholestes. I thus only specified Ornitholestes to be closer to Allosaurus than megalosaurids, piatnitzkysaurids, Compsognathus and birds. The resulting tree has ornitholestiids (including Zuolong) sister to core allosauroids including Monolophosaurus (which was considered closer to Allosaurus by Paul too- pg. 307), but tyrannosauroids and compsognathids are coelurosaurs.
24 steps- Ornithuran (sensu Gauthier) alvarezsaurids. The most crownward alvarezsaurids were ever proposed to be, closer to Aves than Archaeopteryx. They end up just crownward of anchiornithids, and weirdly form a clade there with scansoriopterygids and oviraptorosaurs. As usual, the absence of parvicursorines probably affects the numbers.
24 steps- Archaeopterygid Protarchaeopteryx, as in Paul (2002). Xiaotingia and scansoriopterygids are also closer to Archaeopteryx than Aves in these trees.
25 steps- Tyrannosauroids sister to Pennaraptora, as in Sereno (1999). Like Sereno's trees, alvarezsauroids and therizinosaurs (Beipiaosaurus) form an expanded Arctometatarsalia, though now joined by Ornitholestes, Aorun and Compsognathus. Coelurus becomes a tyrannosauroid.
26 steps- Ornithischian alvarezsaurids, as in Alifanov and Barsbold (2009). Chilesaurus emerges as an alvarezsauroid. Note the true number is probably much higher since neither included alvarezsaurid has cranial material.
30 steps- Ceratosaurian ornithomimosaurs, as in my half-joking post. They don't even come out by Limusaurus or Elaphrosaurus, instead Ornithomimosauria (including Zuolong and Gualicho) are sister to other ceratosaurs. How disappointing.
35 steps- Sauropodomorphan Beipiaosaurus. Falcarius stays by oviraptorosaurs, while Beipiaosaurus ends up sister to Guaibasaurus.
35 steps- Phytodinosaurian Beipiaosaurus. Falcarius stays by oviraptorosaurs, while Beipiaosaurus is sister to Chilesaurus as an ornithischian.
36 steps- Ornithomimosaurian Elaphrosaurus. Gualicho follows, and ornithomimosaurs move stemward to be sister to Tyrannoraptora.
36 steps- Megalosaurid abelisauroids, as in Paul (1988). Megalosaurus moves to Abelisauria.
36 steps- Dromaeosaurid Ornitholestes, as in Makovicky (1995). Fukuivenator emerges as the most basal dromaeosaurid, and dromaeosaurids are the most basal pennaraptorans with oviraptorosaurs, scansoriopterygids, anchiornithids and troodontids successively closer to birds. This is equivalent to my old post about getting dromaeosaurid evolution backwards.
37 steps- Bullatosauria. This actually moves ornithomimosaurs plus alvarezsauroids into Avialae to be sister to troodontids. I had to specify both Zanabazar and Sinornithoides as troodontids, because specifying Zanabazar alone moves it into Ornithomimosauria without the other troodontids at a lower cost of 21 steps.
37 steps- Oviraptorosaurian Sapeornis, as in Paul (2010). Oviraptorosaurs move to just closer to Aves than Archaeopteryx, with scansoriopterygids closer to core oviraptorosaurs than Sapeornis.
39 steps- Huene's (1923) Carnosauria vs. Coelurosauria dichotomy. For such an archaic concept, this works surprisingly well. The trick is that Huene's and Cau's Carnosauria are basically the same. By 1923, Huene had moved Ceratosaurus to Coelurosauria and placed tyrannosaurids and Elaphrosaurus there as well. His carnosaurs are Megalosaurus, Eustreptospondylus and Allosaurus. Even looking at the taxa not included in Cau's analysis, most shake out right- coelurosaurian Sarcosaurus, Halticosaurus, Procompsognathus, Podokesaurus, Betasuchus, Genyodectes, Proceratosaurus and Thecocoelurus vs. carnosaurian Magnosaurus, Poekilopleuron, Spinosaurus and Metriacanthosaurus. There's a load of non-theropods in there and Huene got Sarcosaurus? andrewsi, Dryptosaurus and Valdoraptor wrong, but still impressive. So this basically how many steps it takes to force carnosaurs stemward of Ceratosauria sensu lato.
43 steps- Sauriurine enantiornithines, as in Martin (1983). Basically constraining enantiornithines (Bohaiornis and Cruralispennia here) as closer to Archaeopteryx than to Aves. Rahonavis and Balaur emerge as sauriurines, but surprisingly scansoriopterygids, Sapeornis, jeholornithids, Confuciusornis, Zhongjianornis and Protopteryx remain as closer to Aves ('Ornithurae' in BANDit terminology).
57 steps- Sauriurine enantiornithines and Confuciusornis, as in Hou et al. (1995). This is more in line with BANDit thought, as not only enantiornithines, Archaeopteryx and Confuciusornis fall out as sauriurines, but also Protopteryx, Sapeornis, jeholornithids (Martin, 2004), Vorona (Kurochkin, 2006), Rahonavis and Xiaotingia (those two as archaeopterygids). Unlike the plus 43 step tree, scansoriopterygids are outside Sauriurae plus 'Ornithurae' similar to Czerkas' hypothesis.
58 steps- Abelisaurid Piatnitzkysaurus, as in Currie and Zhao (1994). Condorraptor follows, Eoabelisaurus also becomes an abelisaurid.
75 steps- 'Carnosauria' vs. 'Oviraptorosauria' of Russell and Dong (1994). The Alxasaurus description is my most nostalgic technical paper, because it was the first I tracked down that wasn't in Science or Nature. The authors presented a strange new analysis of theropods, where tetanurines fell into 'Carnosauria' (Baryonyx, Yangchuanosaurus, Allosaurus, dromaeosaurids and tyrannosaurids in successive order) and 'Oviraptorosauria' (ornithomimosaurs, therizinosauroids, oviraptorosaurs and troodontids in successive order). Needless to say, it doesn't hold up, even when topology within each clade is allowed to vary like it is here. Birds end up in 'Oviraptorosauria', so that would be Coelurosauria under current nomenclature.
78 steps- "Pneumatocrania", Holtz's (1994) concept combining oviraptorids, 'elmisaurids', tyrannosaurids, troodontids and ornithomimosaurs to the exclusion of dromaeosaurids and birds. Cau's matrix doesn't result in anything close to Holtz's topology for this clade, with troodontids sister to oviraptorosaurs (including scansoriopterygids), and ornithomimosaurs sister to tyrannosauroids with alvarezsauroids and therizinosaurs in a trichotomy with Tyrann+Ornithom. As with Bullatosauria, Sinornithoides had to be specified as well.
81 steps- Arctometatarsalia sensu Holtz (1994). This is like "Pneumatocrania" except it excludes oviraptorids. In Cau's analysis, this results in most oviraptorosaurs (including scansoriopterygids) being maniraptorans, but 'elmisaurid' Anzu being sister to Zanabazar deep within Troodontidae. Again unlike Holtz's topology, tyrannosauroids, ornithomimosaurs, alvarezsauroids, therizinosaurians and Fukuivenator are successively closer to troodontids.
84 steps- Huene's Pachypodosauria, where his carnosaurs are closer to sauropodomorphs than his coelurosaurs. Pachypodosauria ends up containing sauropodomorphs and ceratosaurs plus Cau's expanded Carnosauria, with every other theropod a coelurosaur.
[Edit] 100 steps-Conservative BANDit topology. Here I specified taxa with stage III or IV feathers as birds, and retained Heterodontosaurus, Plateosaurus, Herrerasaurus, Coelophysis, Majungasaurus, Megalosaurus, Allosaurus and Sinosauropteryx as dinosaurs
theropods. Forcing birds outside Saurischia, Dinosauria, Dracohors,
Dinosauriformes, etc. is difficult as it is actually easier to get Teleocrater
up in basal Coelurosauria than to break up those clades. But just
breaking up Theropoda into these two clades takes 83 steps.
Tyrannosauroids, ornithomimosaurs, alvarezsauroids and therizinosaurs
group with birds.
140 steps- Coelophysoid birds, as in Raath (1985). Other theropods known at the time were constrained as monophyletic relative to a Coelophysoidea containing rhodesiensis, Archaeopteryx, Hesperornis, Ichthyornis and Meleagris. Bicentenaria, Fukuivenator, halszkaraptorids, scansoriopterygids and paraphyletic anchiornithids end up bridging the gap between coelophysoids and birds.
191+ steps- Kurochkin's (2006) diphyletic birds. BANDit Kurochkin had a weird hypothesis that Archaeopteryx and enantiornithines were theropods, but Confuciusornis, Patagopteryx, Ichthyornis, Hesperornis and of course Aves are birds. These diverged at the typically vague BANDit level of Archosauromorpha or Archosauria, with no comment on where crocodylians, ornithischians, sauropodomorphs, etc. go. It's again very hard to constrain in TNT since the program doesn't let the outgroup (Euparkeria) be specified, so if you constrain the next closest taxon (Teleocrater) to be outside of dinosauromorphs on one side and 'Ornithurae' on another, it's more parsimonious for TNT to force Teleocrater into Ornithothorces than to make that basal divergence. But even a weak version of Kurochkin's hypothesis where Coelophysis and Allosaurus are still theropods and lead to enantiornithines but are more closely related to 'Ornithurae' than Teleocrater, Lagerpeton, Marasuchus, Heterodontosaurus and Plateosaurus results in 191 more steps. Fukuivenator, halszkaraptorids, scansoriopterygids, Balaur and Zhongjianornis end up on the 'ornithurine' line.
Ignoring maniraptoromorphs (so as not to hint at Lori's topology) I'm most surprised by the robusticity of Cau's expanded Carnosauria, the rootward mobility of compsognathid-grade taxa, how unparsimonious carnosaurian megaraptorans are, and how parsimonious ceratosaurian megalosaurids and arctometatarsalian tyrannosaurids are. I think Gualicho is the most interesting theropod right now in terms of just what it is, since its remains are decent but it can pretty easily move between ceratosaurs, tyrannosauroids and ornithomimosaurs. Bicentenaria also finds its way into a suprisingly large number of hypotheses, so deserves a more detailed description.
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Baron, 2017. Pisanosaurus mertii and the Triassic ornithischian crisis: Could phylogeny offer a solution? Historical Biology. DOI: 10.1080/08912963.2017.1410705
Cau, 2018. The assembly of the avian body plan: A 160-million-year long process. Bollettino della Società Paleontologica Italiana. 57(1), 1-25.
Andrea sent me his NEXUS file, but whereas the paper reports 3072 MPTs of 6790 steps, I found 10872 MPTs of that length. Eoraptor and Buriolestes aren't always sauropodomorphs, Pisanosaurus is sometimes an ornithischian, Asilisaurus, Silesaurus and Sacisaurus are an unresolved trichotomy, Enantiornithes can be paraphyletic with Zhongjianornis among them, and Fake Ornithuromorpha is less resolved, as Patagopteryx and Apsaravis can be outside Hongshanornis+Aves, Archaeornithura can be a songlingornithid, etc.. I think Andrea's philosophy would be that these things vary with taxon inclusion, so aren't a definite part of his data. The absence of any included spinosaurids, carcharodontosaurines, parvicursorines or Avimimus unfortunately makes some weird 80s and 90s hypotheses untestable. After six more years of experience, I've added a new category "less likely" because I think that factors like scoring accuracy and taxon inclusion can have a larger influence. As I said in the 2012 post, the corrected TWG matrix needed 15 more steps to get a monophyletic Deinonychosauria which is the most common outcome for TWG matrices today. I'll say the Lori matrix recovers at least one hypothesis found to be "unlikely" here, so even that's not the kiss of death.
Basically ambiguous
0 steps- Maniraptoromorph Compsognathus.
0 steps- Megaraptoran Gualicho.
1 step- Ceratosaurus closer to abelisauroids than Elaphrosaurus.
1 step- Megalosauroid piatnitzkysaurids.
1 step- Coelurosaurian Zuolong. Ends up as a basal maniraptoromorph between Coelurus and Ornitholestes.
1 step- Coelurid Aorun, as in its original description. It moves to Maniraptoromorpha with Coelurus.
1 step- Coelurid Tanycolagreus, as in its original description. Coelurus moves into Tyrannosauroidea with Tanycolagreus.
1 step- Compsognathid Sinosauropteryx and/or Sinocalliopteryx.
1 step- Tyrannosauroid Sinocalliopteryx or Coelurus.
1 step- Anchiornithid or archaeopterygid Xiaotingia.
1 step- Scansoriopterygids closer to Aves than Archaeopteryx.
1 step- Sapeornis closer to Aves than Confuciusornis.
1 step- Zhongjianornis sister to Pygostylia, as in its original description.
1 step- Ichthyornis closer to Aves than Hesperornis, the consensus until the recent cranial redescription of Ichthyornis.
2 steps- Theropodan Eodromaeus.
2 steps- Chilesaurus just outside Avepoda, which was my best guess back in 2015 considering the results of its original misscored matrices and my subjective feelings of what would plausibly reverse.
2 steps- Ceratosaurian Gualicho. It has an uncertain placement within the clade, though is excluded from Abelisauria.
2 steps- Megaraptora as coelurosaurs just outside of Tyrannoraptora. This was my result back in 2010 after adding Benson's Neovenatoridae data to my theropod supermatrix (since superseded by the Lori analysis). Bicentenaria is at this level too, while Guanlong and Tanycolagreus become maniraptoromorphs.
2 steps- Maniraptoran Ornitholestes.
2 steps- Hongshanornithid Parahongshanornis, as in its original description.
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| Cast YPM 56693 of the Mononykus olecranus holotype pes in plantar view, courtesy of Senter. |
Quite likely to be true
3 steps- Saurischia. Herrerasaurs and Eodromaeus are theropods. Note that while some of these constraints were tested in the Ornithoscelida paper, the studies differ in both taxonomic content and characters used, so that MegaMatrix results don't necessarily correlate with Ornithoscelida paper results and should not be seen as scooping anything we find.
3 steps- Ornithischian Daemonosaurus. Chilesaurus is sister to Averostra.
3 steps- Theropodan Herrerasaurus/Tawa/Daemonosaurus. These each take three steps more, and other herrerasaurs follow when one is constrained.
3 steps- Dilophosaurid Liliensternus, as in Paul (1988).
3 steps- Ceratosauria sensu lato, combining Neoceratosauria and Coelophysoidea. Chilesaurus is the most basal theropod, Elaphrosaurus plus Limusaurus are the basal neoceratosaurs, and Gualicho is the most basal tetanurine.
3 steps- Eustreptospondylus and/or Megalosaurus outside Avetheropoda. If one is constrained, the other follows.
3 steps- Megaraptoran Eotyrannus, as in Novas et al. (2013).
3 steps- Maniraptoran Coelurus.
3 steps- Troodontid Aurornis, Anchiornis and/or Xiaotingia.
3 steps- Chongmingia sister to Ornithothoraces, as in p2 of its original description.
4 steps- Ornithischian silesaurids. Lewisuchus is outside Dinosauria, Saurischia exists, and Asilisaurus and Pisanosaurus form a silesaur grade to either side of Silesauridae.
4 steps- Phytodinosauria. Eoraptor and Buriolestes are sister to Dinosauria, while herrerasaurs and Eodromaeus are theropods.
4 steps- Ornithischian Chilesaurus. Ornithoscelida occurs.
4 steps- Theropodan Eoraptor. Buriolestes, herrerasaurs and Eodromaeus also theropods.
4 steps- Abelisaurid Eoabelisaurus, as in its original description.
4 steps- Metriacanthosaurids outside Allosauria (Allosaurus plus Carcharodontosaurus). Acrocanthosaurus joins Neovenator, so this also covers carcharodontosaurid Neovenator.
4 steps- Tyrannosauroid Compsognathus, as in Olshevsky (1991). Surprised this one is so parsimonious. A Compsognathidae with Aorun, Bicentenaria and Sinosauropteryx are the basalmost tyrannosauroids, with Sinocalliopteryx, Coeluridae including Tanycolagreus and Guanlong successively closer to core tyrannosauroids.
4 steps- Maniraptoromorph Tanycolagreus and/or Guanlong.
4 steps- Ornithomimosaurian Gualicho. Tested due to Rauhut (2003) finding the very similar Deltadromeus in this position. Note that ornithomimosaurian Elaphrosaurus is 36 steps longer, so the cases aren't that similar.
4 steps- Therizinosaurian Jianchangosaurus. Still outside Falcarius plus Beipiaosaurus, and Cau said in a comment to the last post Jianchangosaurus was still an alvarezsauroid even after adding Erlikosaurus and Shuvuuia. I'm not revealing much by saying the Lori analysis finds Jianchangosaurus to be a therizinosaur between Falcarius and Beipiaosaurus as in its original description. Seems fishy...
4 steps- Archaeopterygid Jinfengopteryx, as in its original description.
4 steps- Archaeopterygid Anchiornis.
4 steps- Oviraptorosaurian scansoriopterygids. They have an uncertain position within the clade, and therizinosaurs are still sister to oviraptorosaurs.
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| Allosaurus fragilis holotype tooth (YPM 1930) in ?lingual view. Courtesy of the YPM. |
5 steps- Dilophosaurus/Cryolophosaurus closer to Averostra than Coelophysis.
5 steps- Non-avetheropod Compsognathus, as in Novas (1992). Very surprised this is so easy to get. It's even more extreme than Novas' version, where Compsognathus was at least closer to avetheropods (his Tetanurae) than Piatnitzkysaurus and Eustreptospondylus, because in the constrained trees Carnosauria still has the same content as Cau's MPTs. Sinosauropteryx joins it.
5 steps- Maniraptoromorph Eotyrannus. I'm surprised by this, since I figured the result in other matrices was due to a lack of tyrannosauroid characters, which I think are all in the MegaMatrix.
5 steps- Non-tyrannoraptoran Coelurus, as in Paul (1988).
5 steps- Avemetatarsalian alvarezsauroids, as in Sereno (1999). Jianchangosaurus is still a basal alvarezsauroid.
5 steps- Haplocheirus compsognathid/coelurid grade, as in Alifanov and Saveliev (2011). Wasn't there some analysis that recovered it here too? I just constrained it to be outside Maniraptoriformes (including alvarezsaurids).
5 steps- Non-pennaraptoran therizinosaurs, which fall out sister to Pennaraptora like the current consensus.
5 steps- Chongmingia a basal ornithurine (sensu Gauthier) outside Shenzhouraptor and Pygostylia, as in p1 of its original description. The Lori analysis recovers it in a different position than p1, p2 or Cau's analysis.
Less likely
6 steps- Non-eusaurischian saurischian Eoraptor. Buriolestes follows, but herrerasaurs and Eodromaeus are theropods.
6 steps- Theropodan Guaibasaurus. Non-dinosaurian Eoraptor and Buriolestes, and this recovers Phytodinosauria.
6 steps- Eustreptospondylus closer to Neotetanurae than Megalosaurus, as in Holtz (2000). I'm actually surprised this is so unlikely.
6 steps- Carnosaurian Sinosauropteryx, as in Longrich (2002). Though Longrich's phylogeny was a bit different in having megalosaurids and metriacanthosaurids outside Avetheropoda.
6 steps- Ornithomimosaurian Haplocheirus, as in the Bayesian analyses of Cau and Lee and Worthy (2011).
6 steps- Arctometatarsalian therizinosaurs, as in Sereno (1999).
6 steps- Shenzhouraptor closer to Aves than Sapeornis.
7 steps- Sauropodomorph Staurikosaurus but not Herrerasaurus, as in pachypodosaur Staurikosaurus of Kischlat (2000).
7 steps- Megalosauroid Monolophosaurus. Megalosauroidea remains in Carnosauria.
7 steps- Coelurosaurian Neovenator. Not sure if this has been suggested in print before, but I noticed quite a few coelurosaur-like characters when scoring Neovenator for the Lori matrix. It forms the most basal coelurosaur clade with Aorun and Gualicho.
7 steps- Maniraptoran Compsognathus.
7 steps- Paravian alvarezsaurids, though note the lack of parvicursorines probably affects these numbers. They (including Jianchangosaurus and Haplocheirus) emerge as the most basal paravians.
7 steps- Basal paravian Anchiornis, Aurornis, scansoriopterygids, Serikornis and/or Xiaotingia.
7 steps- Archaeopterygid Rahonavis, as in Forster et al. (1998).
7 steps- Fake-Ornithuromorphan Confuciusornis, as in Kurochkin (2006). I really thought this would be more difficult to achieve than enantiornithine Confuciusornis (below).
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| Box of Archaeornithimimus asiaticus elements from AMNH 6576, with my identifications (dc- distal caudal, dt- distal tarsal, pedal except m 1-1 and m 3-2). Is that a proximal metatarsal I in the upper left? Courtesy of the AMNH. |
8 steps- Non-eusaurischian saurischian Herrerasaurus. Eodromaeus and sometimes Eoraptor become herrerasaurs and Buriolestes is one node more stemward.
8 steps- Tetanurine Cryolophosaurus, as in Carrano et al. (2002). Dilophosaurus stays in Coelophysoidea.
8 steps- Ceratosaurian megalosaurids, as in Britt (1991). Chilesaurus falls out in a polytomy with megalosaurids and other ceratosaurs.
8 steps- Megalosauroid piatnitzkysaurids, with Megalosauroidea outside Avetheropoda. Since this is the Carrano et al. consensus, I thought it would take less steps.
8 steps- Monolophosaurus sister to Avetheropoda, as in Smith et al. (2007). Megalosaurids and piatnitzkysaurids fall out as more basal tetanurines.
8 steps- Arctometatarsalian tyrannosauroids, AKA Tyrannosaurus closer to Ornithomimus than to birds as in Holtz (1994). I'm very surprised this is so parsimonious. Coelurus and Bicentenaria join Tyrannosauroidea, but Gualicho leaves to be a ceratosaur.
8 steps- Maniraptoran tyrannosauroids, as in Sereno (1999). This is accomplished more by moving ornithomimosaurs (including Gualicho) stemward to be the most basal coelurosaurs except for Zuolong.
Somewhat possible
9 steps- Classic late 80s to early 90s topology where Staurikosaurus is sister to Herrerasaurus plus Dinosauria. Tawa plus Daemonosaurus are closer to dinosaurs than both, while Sanjuansaurus follows Herrerasaurus.
9 steps- Piatnitzkysaurus outside Orionides, as in Rauhut (2003). Condorraptor follows Piatnitzkysaurus, and megalosauroids fall outside Avetheropoda. Surprised this is so high.
9 steps- Carnosaurian Tyrannosaurus, which brings megaraptorans, Gualicho and Bicentenaria to form the sister group of Allosauroidea (including Monolophosaurus). I bet this is more parsimonious than most readers would assume given published topologies over the past two decades.
9 steps- Avialan Caudipteryx, as in its original description. The rest of Oviraptorosauria follows it, though troodontids are still closer to Aves.
9 steps- Avialan Microraptor, as in Agnolin and Novas (2013). Weirdly becomes the most basal troodontid, with that family closer to Aves than scansoriopterygids and anchiornithids.
9 steps- Avialan Unenlagia, as in its original description and Agnolin and Novas (2013). Halszkaraptorines are unenlagiids, which are outside the Troodontidae plus Ornithes clade.
9 steps- Deinonychosauria. Scansoriopterygids are oviraptorosaurs, while Jinfengopteryx and anchiornithids are avialans.
9 steps- Archaeopterygidae sister to Troodontidae. Anchiornithines fall out as archaeopterygids.
10 steps- Monolophosaurus outside Orionides, as in Carrano et al. (2002). Megalosaurids and piatnitzkysaurids form successively closer outgroups to Avetheropoda.
10 steps- Fukuivenator excluded from Alvarezsauridae plus Therizinosauria plus Pennaraptora as in its original description. It emerges as the sister to other maniraptorans.
10 steps- Eumaniraptora excluding troodontids as in Agnolin and Novas (2013). Scansoriopterygids are oviraptorosaurs.
10 steps- Dromaeosaurid Xiaotingia, as in Senter et al. (2012). Falls out in Microraptoria.
10 steps- Dromaeosaurid Balaur, as in its original description. Falls out sister to Unenalagiinae plus Halszkaraptorinae.
11 steps- Tyrannosauroid Acrocanthosaurus, as in Bakker et al. (1988). Tyrannosauroids become carnosaurs, with Sinraptor, Acrocanthosaurus and Bicentenaria successively closer to the 'core tyrannosauroid' clade of Eotyrannus, Gualicho, megaraptorans and Tyrannosaurus. Tanycolagreus and Guanlong are now maniraptoromorphs.
11 steps- Alvarezsauroid Nqwebasaurus. Alvarezsauroids emerge sister to ornithomimosaurs, with Haplocheirus and Jianchangosaurus forming a basal [edit] arctometatarsalian clade.
11 steps- Mahakala outside Unenlagiinae plus Eudromaeosauria (Halszkaraptor follows), as in most TWG matrices (though Senter et al. 2012 recovered it sister to unenlagiines like Cau).
Unlikely
12 steps- Alvarezsauroid Chilesaurus, where it emerged in the Lori matrix back in 2015.
12 steps- Ornithuran (sensu Gauthier) oviraptorosaurs, as in Maryanska et al. (2002). Constraining Khaan to be closer to Meleagris than Archaeopteryx results in oviraptorosaurs (including scansoriopterygids) being the first clade to diverge from the avian stem after Archaeopteryx.
12 steps- Basal paravian Jinfengopteryx, as in Foth et al. (2014).
13 steps- Coelophysoid Elaphrosaurus, as in Paul (1988). Ceratosauria sensu lato forms, Elaphrosaurus is outside core coelophysoids and Limusaurus and sometimes Gualicho follow.
13 steps- Compsognathid Nqwebasaurus, as in Novas et al. (2013). Compsognathids (including Aorun) become ornithomimosaurs.
13 steps- Dromaeosaurid Rahonavis. Emerges in the unenalgiine plus halszkaraptorine clade.
14 steps- Neovenatorid megaraptorans, though this actually moves Neovenator out of Carnosauria into Tyrannosauroidea, so isn't that similar to Benson's topology.
14 steps- Enantiornithine Confuciusornis.
15 steps- Sauropodomorphan Chilesaurus, where it emerges as the most basal member.
15 steps- Carnosaurian Ceratosaurus, as in Currie (1995). Other ceratosaurs follow.
15 steps- Alvarezsaurids closer to Aves than dromaeosaurids or troodontids. Haplocheirus and Jianchangosaurus remain behind as ornithomimosaurs. Note the lack of parvicursorines probably affects this number.
15 steps- Archaeopterygid Unenlagia, as in Forster et al. (1998). Buitreraptor remains in Dromaeosauridae.
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| Cladogram of archosauromorphs after Kischlat (2000). Note saurischian Marasuchus and sauropodomorph Staurikosaurus. |
16 steps- Saurischian Marasuchus, as in Kischlat (2000). Ornithischian silesaurs result, and Lewisuchus sister to Eodromaeus plus avepods.
16 steps- Non-avetheropod Sinraptor as in Longrich (2002). Carnosauria becomes a grade, Acrocanthosaurus joins Neovenator, and Guanlong and Tanycolagreus become maniraptoromorphs.
18 steps- Basal paravian Archaeopteryx. Deinonychosauria forms, and anchiornithids and scansoriopterygids are further from Eumaniraptora.
19 steps- Coelophysoid ornithischians or ornithischians sister to Neotheropoda, as in Baron (2017). Chilesaurus is the most basal theropod.
19 steps- Basal deinonychosaur Archaeopteryx, as in Xu et al. (2011). Anchiornis, Aurornis and Serikornis are one node closer to Dromaeosauridae plus Troodontidae.
20 steps- Monolophosaurus sister to Guanlong, as in Carr (2006) who proposed they were an adult and juvenile of the same species. The pairing resolves as sister to Tyrannoraptora.
21 steps- Carnosaurian megaraptorans. Er, wow. The Carrano et al. consensus is blown out of the water. They don't even group with Neovenator, instead (including Gualicho and Bicentenaria) being in a trichotomy with megalosaurids and an Allosauroidea including piatnitzkysaurids.
I'm drawing the line here for plausibility
22 steps- Theropodan Marasuchus, as in Olshevsky (1991). Silesaurids, Eoraptor+Buriolestes and herrerasaurians are also theropods.
23 steps- Avialan therizinosaurs, as in Maryanska et al. (2002). One of the odder parts of the classic 'oviraptorosaurs are birds' analysis is that they recovered therizinosaurs as closer to birds than dromaeosaurids or troodontids, which was only briefly mentioned in the text, while they removed Troodontidae and Therizinosauria from their figured cladogram. Constraining this result leads to oviraptorosaurs being dragged along, and the whole of Caenagnathiformes is sister to taxa closer to Aves like scansoriopterygids, anchiornithids, Archaeopteryx, etc..
24 steps- 'Allosaur' Ornitholestes, as in Paul (1988). Although Paul includes Ornitholestes in his Allosauridae, he views that family as paraphyletic to tyrannosaurids and his figure 10-1 shows Allosaurus closer to tyrannosaurids than Ornitholestes. I thus only specified Ornitholestes to be closer to Allosaurus than megalosaurids, piatnitzkysaurids, Compsognathus and birds. The resulting tree has ornitholestiids (including Zuolong) sister to core allosauroids including Monolophosaurus (which was considered closer to Allosaurus by Paul too- pg. 307), but tyrannosauroids and compsognathids are coelurosaurs.
24 steps- Ornithuran (sensu Gauthier) alvarezsaurids. The most crownward alvarezsaurids were ever proposed to be, closer to Aves than Archaeopteryx. They end up just crownward of anchiornithids, and weirdly form a clade there with scansoriopterygids and oviraptorosaurs. As usual, the absence of parvicursorines probably affects the numbers.
24 steps- Archaeopterygid Protarchaeopteryx, as in Paul (2002). Xiaotingia and scansoriopterygids are also closer to Archaeopteryx than Aves in these trees.
25 steps- Tyrannosauroids sister to Pennaraptora, as in Sereno (1999). Like Sereno's trees, alvarezsauroids and therizinosaurs (Beipiaosaurus) form an expanded Arctometatarsalia, though now joined by Ornitholestes, Aorun and Compsognathus. Coelurus becomes a tyrannosauroid.
26 steps- Ornithischian alvarezsaurids, as in Alifanov and Barsbold (2009). Chilesaurus emerges as an alvarezsauroid. Note the true number is probably much higher since neither included alvarezsaurid has cranial material.
30 steps- Ceratosaurian ornithomimosaurs, as in my half-joking post. They don't even come out by Limusaurus or Elaphrosaurus, instead Ornithomimosauria (including Zuolong and Gualicho) are sister to other ceratosaurs. How disappointing.
35 steps- Sauropodomorphan Beipiaosaurus. Falcarius stays by oviraptorosaurs, while Beipiaosaurus ends up sister to Guaibasaurus.
35 steps- Phytodinosaurian Beipiaosaurus. Falcarius stays by oviraptorosaurs, while Beipiaosaurus is sister to Chilesaurus as an ornithischian.
36 steps- Ornithomimosaurian Elaphrosaurus. Gualicho follows, and ornithomimosaurs move stemward to be sister to Tyrannoraptora.
36 steps- Megalosaurid abelisauroids, as in Paul (1988). Megalosaurus moves to Abelisauria.
36 steps- Dromaeosaurid Ornitholestes, as in Makovicky (1995). Fukuivenator emerges as the most basal dromaeosaurid, and dromaeosaurids are the most basal pennaraptorans with oviraptorosaurs, scansoriopterygids, anchiornithids and troodontids successively closer to birds. This is equivalent to my old post about getting dromaeosaurid evolution backwards.
37 steps- Bullatosauria. This actually moves ornithomimosaurs plus alvarezsauroids into Avialae to be sister to troodontids. I had to specify both Zanabazar and Sinornithoides as troodontids, because specifying Zanabazar alone moves it into Ornithomimosauria without the other troodontids at a lower cost of 21 steps.
37 steps- Oviraptorosaurian Sapeornis, as in Paul (2010). Oviraptorosaurs move to just closer to Aves than Archaeopteryx, with scansoriopterygids closer to core oviraptorosaurs than Sapeornis.
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| Phylogram from Huene (1923) showing his idea of what were carnosaurs vs. coelurosaurs. |
39 steps- Huene's (1923) Carnosauria vs. Coelurosauria dichotomy. For such an archaic concept, this works surprisingly well. The trick is that Huene's and Cau's Carnosauria are basically the same. By 1923, Huene had moved Ceratosaurus to Coelurosauria and placed tyrannosaurids and Elaphrosaurus there as well. His carnosaurs are Megalosaurus, Eustreptospondylus and Allosaurus. Even looking at the taxa not included in Cau's analysis, most shake out right- coelurosaurian Sarcosaurus, Halticosaurus, Procompsognathus, Podokesaurus, Betasuchus, Genyodectes, Proceratosaurus and Thecocoelurus vs. carnosaurian Magnosaurus, Poekilopleuron, Spinosaurus and Metriacanthosaurus. There's a load of non-theropods in there and Huene got Sarcosaurus? andrewsi, Dryptosaurus and Valdoraptor wrong, but still impressive. So this basically how many steps it takes to force carnosaurs stemward of Ceratosauria sensu lato.
43 steps- Sauriurine enantiornithines, as in Martin (1983). Basically constraining enantiornithines (Bohaiornis and Cruralispennia here) as closer to Archaeopteryx than to Aves. Rahonavis and Balaur emerge as sauriurines, but surprisingly scansoriopterygids, Sapeornis, jeholornithids, Confuciusornis, Zhongjianornis and Protopteryx remain as closer to Aves ('Ornithurae' in BANDit terminology).
57 steps- Sauriurine enantiornithines and Confuciusornis, as in Hou et al. (1995). This is more in line with BANDit thought, as not only enantiornithines, Archaeopteryx and Confuciusornis fall out as sauriurines, but also Protopteryx, Sapeornis, jeholornithids (Martin, 2004), Vorona (Kurochkin, 2006), Rahonavis and Xiaotingia (those two as archaeopterygids). Unlike the plus 43 step tree, scansoriopterygids are outside Sauriurae plus 'Ornithurae' similar to Czerkas' hypothesis.
58 steps- Abelisaurid Piatnitzkysaurus, as in Currie and Zhao (1994). Condorraptor follows, Eoabelisaurus also becomes an abelisaurid.
75 steps- 'Carnosauria' vs. 'Oviraptorosauria' of Russell and Dong (1994). The Alxasaurus description is my most nostalgic technical paper, because it was the first I tracked down that wasn't in Science or Nature. The authors presented a strange new analysis of theropods, where tetanurines fell into 'Carnosauria' (Baryonyx, Yangchuanosaurus, Allosaurus, dromaeosaurids and tyrannosaurids in successive order) and 'Oviraptorosauria' (ornithomimosaurs, therizinosauroids, oviraptorosaurs and troodontids in successive order). Needless to say, it doesn't hold up, even when topology within each clade is allowed to vary like it is here. Birds end up in 'Oviraptorosauria', so that would be Coelurosauria under current nomenclature.
78 steps- "Pneumatocrania", Holtz's (1994) concept combining oviraptorids, 'elmisaurids', tyrannosaurids, troodontids and ornithomimosaurs to the exclusion of dromaeosaurids and birds. Cau's matrix doesn't result in anything close to Holtz's topology for this clade, with troodontids sister to oviraptorosaurs (including scansoriopterygids), and ornithomimosaurs sister to tyrannosauroids with alvarezsauroids and therizinosaurs in a trichotomy with Tyrann+Ornithom. As with Bullatosauria, Sinornithoides had to be specified as well.
81 steps- Arctometatarsalia sensu Holtz (1994). This is like "Pneumatocrania" except it excludes oviraptorids. In Cau's analysis, this results in most oviraptorosaurs (including scansoriopterygids) being maniraptorans, but 'elmisaurid' Anzu being sister to Zanabazar deep within Troodontidae. Again unlike Holtz's topology, tyrannosauroids, ornithomimosaurs, alvarezsauroids, therizinosaurians and Fukuivenator are successively closer to troodontids.
84 steps- Huene's Pachypodosauria, where his carnosaurs are closer to sauropodomorphs than his coelurosaurs. Pachypodosauria ends up containing sauropodomorphs and ceratosaurs plus Cau's expanded Carnosauria, with every other theropod a coelurosaur.
[Edit] 100 steps-
140 steps- Coelophysoid birds, as in Raath (1985). Other theropods known at the time were constrained as monophyletic relative to a Coelophysoidea containing rhodesiensis, Archaeopteryx, Hesperornis, Ichthyornis and Meleagris. Bicentenaria, Fukuivenator, halszkaraptorids, scansoriopterygids and paraphyletic anchiornithids end up bridging the gap between coelophysoids and birds.
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| Paul's (1984) cladogram of predatory dinosaurs, after Raath (1990). It differs from Paul's actual printed cladogram where compsognathids are better interpreted as in an unresolved trichotomy between 'allosaurs' and other coelurosaurs, ornithomimids merely extend with a '?' falling between tyrannosaurids and Archaeopteryx, and oviraptorids extend with a '?' that falls on the troodontid plus bird branch. Note this differs from the PDW phylogeny in that megalosaurids are down by Procompsognathus and tyrannosaurids are sister to Protoavia. |
191+ steps- Kurochkin's (2006) diphyletic birds. BANDit Kurochkin had a weird hypothesis that Archaeopteryx and enantiornithines were theropods, but Confuciusornis, Patagopteryx, Ichthyornis, Hesperornis and of course Aves are birds. These diverged at the typically vague BANDit level of Archosauromorpha or Archosauria, with no comment on where crocodylians, ornithischians, sauropodomorphs, etc. go.
Ignoring maniraptoromorphs (so as not to hint at Lori's topology) I'm most surprised by the robusticity of Cau's expanded Carnosauria, the rootward mobility of compsognathid-grade taxa, how unparsimonious carnosaurian megaraptorans are, and how parsimonious ceratosaurian megalosaurids and arctometatarsalian tyrannosaurids are. I think Gualicho is the most interesting theropod right now in terms of just what it is, since its remains are decent but it can pretty easily move between ceratosaurs, tyrannosauroids and ornithomimosaurs. Bicentenaria also finds its way into a suprisingly large number of hypotheses, so deserves a more detailed description.
References- Huene, 1923. Carnivorous Saurischia in Europe since the Triassic. Bulletin of the Geological Society of America. 34, 449-458.
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