Home > Progress Reports, To-Do List > Behold, The Mighty Cladogram

Behold, The Mighty Cladogram

It’s taken awhile, but I finally put together a basic phylogeny to provide the evolutionary backbone for our phylogenetically-informed analyses. References (in very abbreviated format – we’ll have to flesh it out more for the paper) are given at the end of this post.

I created a “pseudo-supertree”, based on a number of what I (in my opinion) consider to be some of the better and more up-to-date published cladistic analyses. The vast majority of our species of interest are included here, and a draft is shown later in the post. But, we need your help in order to get to the final product.

Here’s What You Can Do
Below is a list of taxa that are not yet placed on the cladogram. In all cases, they were not featured in any of the cladistic analyses I looked at for my first pass. In order to incorporate them into the analysis effectively, though, we need to figure out where they belong. So. . .I’m looking for anything – a reference, personal opinion, cladogram I missed – to place them on the tree. Please mention it in the comments, and we’ll be able to get the tree updated! At the minimum, a reference would be helpful, so that we can be as explicit as possible in our reasoning for the paper. I focused my efforts so far on just ornithischians, so many of the problematic taxa are recently-published animals that are outside Ornithischia.

Also, if you see anything in the tree that you consider to be in gross error, please put a note in the comments section, and we can talk about it. We want the best phylogeny possible. But at the same time, studies have shown that some phylogeny – any phylogeny – is better than no phylogeny at all, so we don’t have to sweat things too much if new data later force us to revise.

Taxa to Place
Ankylosauria:
Aletopelta coombsi, Dracopelta zbyszewskii, Dyoplosaurus acutosquameus, Hungarosaurus tormai, Niobrarasaurus coleii, Nodosaurus textilis, Polacanthus foxii, Zhejiangosaurus lishuiensis
Ceratopsia: Graciliceratops mongoliensis, Psittacosaurus major, Psittacosaurus mongoliensis, Psittacosaurus neimongoliensis, Psittacosaurus ordosensis, Psittacosaurus sibiricus, Psittacosaurus sinensis, Psittacosaurus xinjiangensis, Xuanhuaceratops niei
Crurotarsi: Gracilisuchus stipanicicorum, Hallopus victor, Protosuchus richardsoni, Saurosuchus galilei, Pseudolagosuchus major, Scleromochlus taylori
Hadrosauroidea: Anatotitan copei (is there a consensus that this is just Edmontosaurus?), Barsboldia sicinskii, Claosaurus affinis, Edmontosaurus saskatchewanensis (how does it relate to other Edmontosaurus species?), Hadrosaurus foulkii, Mandschurosaurus amurensis, Shantungosaurus giganteus
Basal ornithischians: Eocursor parvus, Geranosaurus atavus
Ornithopods: Draconyx loureiroi, Gongbusaurus wucaiwanensis, Oryctodromeus cubicularis, Xiaosaurus dashanpensis
Parasuchia: Machaeroprosopus gregorii
Sauropodomorpha: Aardonyx celestae, Gyposaurus sinensis, Panphagia protos, Pantydraco caducus, Sellosaurus gracilis
Stegosauria: Chialingosaurus kuani, Lexovisaurus durobrivensis
Theropoda: Guaibasaurus candelariensis, Podokesaurus holyokensis

The Phylogeny

The Phylogeny, as of 4 March 2010. Click to see it in all of its glory.

Logic Behind the Tree
In the interest of Open Notebook Science, I have provided full references and justifications (if any) for the topology of the illustrated tree. All of this should go into the final paper, so that others can reproduce our work.

Overall topology of Ornithischia:
From Butler et al. 2008, Figures 2, 3, and 4, with additional modifications from Butler et al. 2009, Figure S4
Contents of Thyreophora (Lesothosaurus, Scutellosaurus, Emausaurus, Scelidosaurus, Stegosauria, Ankylosauria) based on this phylogeny
Placement of Stenopelix within Pachycephalosauria based on this phylogeny (2009).
Position of Heterodontosauridae follows this reference (2008), as do positions of Stormbergia, Agilisaurus, and Hexinlusaurus.
The position of Othnielia (Othnielosaurus) follows Figures 2 (50% majority rule part), 3, and 4. (2008)
The position of Orodromeus follows Figures 3 and 4. (2008)
The position of Hypsilophodon relative to Jeholosaurus, Yandusaurus, Orodromeus, and Zephyrosaurus follows Figure 2 (50% majority rule part). (2008)
Jeholosaurus and Yandusaurus are arbitrarily placed as sister taxa. Their position basal to Hypsilophodon follows Fig. 2 (50% majority rule part), and Jeholosaurus‘s position more derived than Orodromeus follows Figure 4. (2008)
Bugenasaura is excluded from the tree following its synonymization with Thescelosaurus by Boyd et al. 2009.
The positioning of Thescelosaurus, Parksosaurus, and Gasparinisaura as more derived than Hypsilophodon and outside of the remaining ornithopods follows Figure 2 (50% majority rule part), Figure, and Figure 4. Thescelosaurus is arbitrarily placed as more derived than Parksosaurus+Gasparinisaura. (2008)
The positioning of Talenkauen follows that of Figure 2 (50% majority rule part). (2008)
The remainder of Ornithopoda is consistent across all versions of the cladogram, and this phylogeny is followed for the positions of Rhabdodontidae, Tenontosaurus, Dryosauridae, and Ankylopollexia.
The problematic taxa Zephyrosaurus, Echinodon, Lycorhinus, were excluded (and do not have postcrania, anyhow).

Topology of Stegosauridae:
From 50% Majority-Rule Consensus Tree of Mateus et al. 2009 (Miragaia paper, supplementary information, Figure S7B)

Topology of Ankylosauria:
From Vickaryous 2004, Figure 17.20 (strict consensus tree)
Pawpawsaurus, Sauropelta, and Silvisaurus were in a polytomy; their positions were assigned arbitrarily. This will not matter ultimately, because Pawpawsaurus and Silvisaurus do not have multiple postcranial elements known, and are thus excluded from the quantitative analysis. Saichania and Talarurus had polytomy arbitrarily resolved, too.

Topology of basal Iguanodontia:
Follows Norman 2004, figures 19.21 (strict consensus) and 19.22 (single most parsimonious tree following taxon deletion).
Tenontosaurus is treated as monophyletic, following Figure 19.22.
Euijuubus is arbitrarily treated as more basal than Lurdusaurus.
Jinzhousaurus and Nanyangosaurus are arbitrarily placed as sister taxa, more basal than Probactrosaurus+Ouranosaurus.
Eolambia+Altirhinus are placed between Ouranosaurus and Protohadros, following Figure 19.21 in Norman 2004.

Topology of basal hadrosaurids, hadrosauroids, and other derived iguanodontians:
Follows Dalla Vecchia 2009, Figure 8B (50% Majority Rule Tree). Bactrosaurus and Gilmoreosaurus are arbitrarily resolved from their polytomy with more derived hadrosauroids. Mantellisaurus and Dollodon are given as sister taxa, following this analysis.

Topology of lambeosaurines:
Follows Evans and Reisz 2007, Figure 9
Corythosaurus arbitrarily resolved as closer to Hypacrosaurus than Olorotitan
Pararhabdodon as a basal lambeosaurine after Dalla Vecchia 2009

Topology of hadrosaurines:
Follows Fig. 16 of Gates and Sampson 2007
Edmontosaurus, Prosaurolophus, and Saurolophus are split into their species, assuming that each genus is monophyletic

Topology of Pachycephalosauridae:
Follows Schott et al. 2009 (Colepiocephale description in JVP 29(3)), Figure 8B. Stygimoloch is removed, following synonymization with Pachycephalosaurus by Horner et al. 2009. Colepiocephale is arbitrarily resolved as sister taxon to Stegoceras.

Topology of Ceratopsia:
For non-ceratopsids, follows Makovicky and Norell 2006, Figure 20A (strict consensus tree)
Placement of Cerasinops, and its relationships with Udanoceratops, Leptoceratops, Montanaceratops, and Prenoceratops, based on Figure 6 of Chinnery and Horner 2007
Placement of Yinlong and Micropachycephalosaurus after Figure S4 of Butler et al. supplementary information

Topology of Ceratopsidae:
Chasmosaurinae after Figure 23.8 of Sampson et al. 2004
Centrosaurinae after Figure 12 of Ryan 2007
Placement of Avaceratops based on unpublished analysis
Placement of Turanoceratops after Farke et al. 2009

Topology of Heterodontosauridae:
Follows Figure S4 of Butler et al. 2009 supplementary information.
Abrictosaurus and Tianyulong are placed arbitrarily.

Topology of basal dinosaurs, dinosauriforms, and dinosauromorphs
After Nesbitt et al. 2010, Figure S1

Topology of saurischians
After Nesbitt et al. 2009, Figure S7

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  1. Ian Browne
    March 5, 2010 at 6:09 am

    Just a couple of questions/comments about the methodology. Just scanning through the references it looks like a pretty good mix of majority rule and strict consensus trees. Is it really justifiable to mix the two? I’ll admit, I don’t generally trust majority rule trees. Also this appears to be a fully resolved tree. With so many of the source trees being consensus trees I’d expect to see at least a few polytomies.

  2. Mickey Mortimer
    March 5, 2010 at 6:53 am

    Well, I could help out at least with the theropods. Podokesaurus should be in a polytomy with Coelophysis and Megapnosaurus (“Syntarsus”), as it’s been universally recognized as a coelophysoid. A character supporting this is the elongate dorsal centra. Guaibasaurus should either be sister to Saturnalia (and Panphagia) or in a polytomy with Tawa and avepods, depending on whose analysis you follow (Langer, 2004 and Yates, 2006 or Ezcurra and Novas, 2009).

    Ezcurra and Novas, 2009. Guaibasauridae, a new clade of Triassic basal sauropodomorphs. Journal of Vertebrate Paleontology. 29(3), 92A.

    Langer, 2004. Basal Saurischia. In Weishampel, Dodson and Osmolska. The Dinosauria Second Edition. University of California Press. 861 pp.

    Yates, 2007. Solving a dinosaurian puzzle: the identity of Aliwalia rex Galton. Historical Biology. 19(1), 93-123.

  3. Jay
    March 5, 2010 at 8:17 am

    Briefly, here are a few points which caught my eye, and perhaps the tree could be updated:

    – Microceratops as an OTU? How about Graciliceratops instead?

    – Pararhabodon & Tsintaosaurus might form a clade, basal to the Parasaurlophinii+Lambeosaurinii clade, within Lambeosaurinae; based on recent work by Prieto-Marquez & Wagner (2010)

    – At the bottom of the tree, there is a clade of ‘Prenocephale’ species, which lay outside the Precephale+Tylocephale clade – the original nomenclature for two of the species in the ‘Prenocephale’ clade was Sphaerotholus goodwini & S. bucholtzae (the latter which Sullivan referred to the species ‘Troodon’ edmontonensis). So, shouldn’t the label for this ‘Prenocephale’ clade be Sphaerotholus instead, and with P. brevis referred?

  4. Jay
    March 5, 2010 at 8:24 am

    Regarding that heap of Psittacosaurus species, Averianov’s monograph on P. sibiricus provided an analysis & cladogram. Granted, many of the species are in a polytomy

  5. March 5, 2010 at 8:41 am

    Following Knoll et al. (2009*), Stormbergia should be considered a junior synonym of Lesothosaurus.

    *Published in 2010, but available online in 2009: Knoll F, Padian K, de Ricqles A, 2009. Ontogenetic change and adult body size of the early ornithischian dinosaur Lesothosaurus diagnosticus: Implications for basal ornithischian taxonomy. Gondwana Research. Available online 15 April 2009, doi:10.1016/j.gr.2009.03.010.

  6. Mickey Mortimer
    March 5, 2010 at 9:41 am

    … and sauropodomorphs, while I’m here. Panphagia should be either the basalmost sauropodomorph (original description), or sister to Saturnalia (Ezcurra and Novas, 2009). Following the Aardonyx paper, the topology for the rest should be- (Pantydraco (Efraasia (Sellosaurus (“Gyposaurus” + Aardonyx)))).

  7. March 5, 2010 at 11:01 am

    Off the top of my head, I recall Ösi (2005) found Hungarosaurus to be a basal nodosaurid. See my post- http://tinyurl.com/yeonalw
    Note, this also provides better resolution for the positions for some higher nodosaurid polytomy.
    Some of the other nodosaurid taxa you mentioned are difficult to include in existing phylogenetic analyses due to the scarcity of postcranial characters. I’m sure diagnostic and phylogenetically relevant postcranial characters exist, but ornithischian workers haven’t made sufficient note of them yet.

    Amurosaurus is possibly closer to the Hypacrosaurus-like lambeosaurines rather than being basal to both the Parasaurolophus-like lambeosaurines and Hypacrosaurus-like lambeosaurines, based on including all of the relevant character information on this taxon. Evans and Reisz did not include postcranial data, and when this information is included, it alters the position of Amurosaurus. PrietoMarquez recovered a similar position for Amurosaurus to what I have suggested.

    I’ll try to check into the rest later.

  8. March 5, 2010 at 11:19 am

    Orcytodromeus-
    Varricchio et al. (2007) recovered it as a sistergroup to the Orodromeus-Zephyrosaurus clade.

    Eocursor-
    If you treat heterodontosaurids as outside of Genasauria following Butler (2008), then I recommend treating Eocursor as being a non-genasaurian ornithischian more derived than heterodontosaurids. (Heterodontosauridae(Eocursor,Genasauria)) This recommendation is following the phylogenetic analysis in Butler et al. (2007) and the commentary in Butler (2009).

    Cedarpelta-
    I’ll go out on a limb and suggest this might be an ankylosaurid rather than a nodosaurid. This is based on my unpublished analysis of ankylosaurians (http://tinyurl.com/yeonalw), and agrees with observations made by Carpenter in his papers on Cedarpelta and the phylogenetic results of Lu et al. (2007).

    Carpenter, Kenneth; Bartlett, Jeff; Bird, John; and Barrick, Reese (2008). “Ankylosaurs from the Price River Quarries, Cedar Mountain Formation (Lower Cretaceous), east-central Utah”. Journal of Vertebrate Paleontology 28 (4): 1089–1101.
    Lü Junchang; Ji Qiang; Gao Yubo; and Li Zhixin (2007). “A new species of the ankylosaurid dinosaur Crichtonsaurus (Ankylosauridae:Ankylosauria) from the Cretaceous of Liaoning Province, China”. Acta Geologica Sinica (English edition) 81 (6): 883–897.
    Varricchio, David J.; Martin, Anthony J.; and Katsura, Yoshihiro (2007). “First trace and body fossil evidence of a burrowing, denning dinosaur”. Proceedings of the Royal Society B: Biological Sciences 274: 1361–1368.
    Butler, Richard J.; Roger M. H. Smith and David B. Norman (2007). “A primitive ornithischian dinosaur from the Late Triassic of South Africa, and the early evolution and diversification of Ornithischia”. Proceedings of the Royal Society B: Biological Sciences 274: 2041.
    BUTLER, R. J. 2009. The anatomy of the basal ornithischian dinosaur Eocursor parvus from the lower Elliot Formation (Late Triassic) of South Africa. Zoological Journal of the Linnean Society (doi:10.1111/j.1096-3642.2009.00631.x)
    Ösi, A. 2005. Hungarosaurus tormai, a new ankylosaur (Dinosauria) from the Upper Cretaceous of Hungary. Journal of Vertebrate Paleontology 25(2):370-383.

  9. March 5, 2010 at 11:29 am

    Protosuchus would be the sistergroup to Dromicosuchus and they would be the most derived crocodylomorphs in your topology.

    Xuanhuaceratops is a sistergroup to Chaoyangsaurus in the topology of Makovicky et al. (2006), it might have been missed by other project participants because it’s listed by specimen number (the paper describing it was in press at the time of publication of the Yamaceratops description).

    Makovicky, Peter J.; and Norell, Mark A. (2006). “Yamaceratops dorngobiensis, a new primitive ceratopsian (Dinosauria: Ornithischia) from the Cretaceous of Mongolia” American Museum Novitates 3530: 1–42

  10. March 5, 2010 at 12:33 pm

    What about the ankylosaurid Nodocephalosaurus kirtlandensis which I believe is closer to the Asian Tarchia-Sachania-like ankylosaurids.

    Sullivan, R.M., 1999, Nodocephalosaurus kirtlandensis gen. et sp. nov., a new ankylosaurid dinosaur (Ornithischia: Ankylosauria) from the Upper Cretaceous (Late Campanian) Kirtland Formation of New Mexico: Journal of Vertebrate Paleontology, v. 19, p. 126-139.

  11. Rob Taylor
    March 5, 2010 at 1:32 pm

    A couple of generic names included in the cladogram that may require attention. In 2008, Octavio Mateus proposed what I thought to be a very elegant solution for the preoccupied names Diceratops and Microceratops, suggesting the replacement names Diceratus and Microceratus, respectively. For better or worse (and I’m inclined to go with the latter), Ukrainsky beat Mateus to the punch on Diceratops, proposing the name Nedoceratops the year prior.

    Mateus O (2008) Two ornithischian dinosaurs renamed: Microceratops Bohlin 1953 and Diceratops Lull 1905. Journal of Paleontology 82: 423.

    Ukrainsky AS (2007) A new replacement name for Diceratops Lull, 1905 (Reptilia: Ornithischia: Ceratopsidae). Zoosystematica Rossica 16: 292.

  12. Andy Farke
    March 5, 2010 at 6:48 pm

    Ian Browne :

    Just a couple of questions/comments about the methodology. Just scanning through the references it looks like a pretty good mix of majority rule and strict consensus trees. Is it really justifiable to mix the two? I’ll admit, I don’t generally trust majority rule trees. Also this appears to be a fully resolved tree. With so many of the source trees being consensus trees I’d expect to see at least a few polytomies.

    Very good point, Ian. . .unfortunately, most (?all) of the methods in use right now require fully resolved phylogenetic trees. We can “fudge” a polytomy by applying really, really short branch lengths, but in the end a requirement for absolute resolution is a (minor) weakness in methods that account for phylogeny.

    And it probably isn’t totally justifiable to mix strict consensus / majority rule trees, but we also can (practically) only work with what’s in the literature. Some aspects of the phylogeny are probably wrong, but again the published simulations show that a slightly wrong phylogeny is far, far better than no phylogeny. We may consider running analyses with an alternate topology or two (e.g., for heterodontosaurid placement), just to see if it affects things much.

  13. 220mya
    March 5, 2010 at 7:12 pm

    I can help out with outgroups:

    Gracilisuchus stipanicicorum: basal to Revueltosaurus + Aetosaurus in the pseudosuchian clade.

    Hallopus victor and Protosuchus richardsoni: These two should be sister taxa, with their closest relative being Dromicosuchus

    Saurosuchus galilei: A separate branch that slots in between Batrachotomus and Postosuchus

    Pseudolagosuchus major: Already in your cladogram with the silesaurs (and thus not a crurotarsan). A note though: right now it is shown as sister to Lewisuchus. When both taxa are included, they do not clade together, but form a basal polytomy in Silesaridae. Though, as discussed by Nesbitt et al. (2010), they are probably the same taxon.

    Scleromochlus taylori: Should be basal-most ornithodiran, outside of pterosaurs + dinosauromorphs.

    Most people have already taken care of the sauropodomorphs. I would advocate Panphagia as the basal-most sauropodomorph rather than sister to Saturnalia. For theropods, Guaibasaurus should be a separate branch that is above herrerasaurids, but below Tawa.

  14. 220mya
    March 5, 2010 at 7:17 pm

    Also, Lesothosaurus should not be within Thryeophora. It should be a separate branch above heterodontosaurids, but below Thyreophora + Genasauria. As Nick points out, Eocursor should be a separate branch in between heterodontosaurids and Lesothosaurus.

  15. Andy Farke
    March 5, 2010 at 7:26 pm

    220mya :

    Also, Lesothosaurus should not be within Thryeophora. It should be a separate branch above heterodontosaurids, but below Thyreophora + Genasauria. As Nick points out, Eocursor should be a separate branch in between heterodontosaurids and Lesothosaurus.

    I followed the Butler et al. 2008 ornithischian phylogeny for that (which is admittedly an unconventional placement for Lesothosaurus), but now see that the 2009 analysis with Fruitadens has the placement you recommend.

    Are there references in particular for Scleromochlus, etc., placements that you gave?

  16. 220mya
    March 5, 2010 at 8:15 pm

    Butler et al. 2007 also has that position; it was actually submitted after Butler et al. 2008, and so represents a slightly more recent version.

    For Gracilisuchus, right now the best is Sterling Nesbitt’s dissertation.

    Protosuchus – there are many refs showing it is a basal crocodyliform. Walker (1970) demonstrated that Hallopus was a non-crocodyliform crocodylomorph, but it has never been put in a strict phylogenetic analysis. But based on my own examination, I do think it is more derived than Dromicosuchus.

    Saurosuchus has always been considered a “rauisuchian”, but Nesbitt’s dissertation is the ref for its specific placement that I give.

    A number of papers give placement for Scleromochlus, but check out in particular Sereno (1991) and Benton (1999).

  17. 220mya
    March 5, 2010 at 8:22 pm

    Sorry, forgot to give the refs themselves:

    Benton, M. J. 1999. Scleromochlus taylori and the origin of dinosaurs and pterosaurs. Philosophical Transactions of the Royal Society of London, Series B 354:1423-1446.

    Nesbitt, S. J. 2009. The early evolution of archosaurs: relationships and the origin of major clades. PhD dissertation, Columbia University, New York, 665 pp.

    Sereno, P. C. 1991. Basal archosaurs: phylogenetic relationships and functional implications. Society of Vertebrate Paleontology Memoir 2:1-53.

    Walker, A. D. 1970. A revision of the Jurassic reptile Hallopus victor (Marsh), with remarks on the classification of crocodiles. Philosophical Transactions of the Royal Society of London, Series B 257:323-372.

  18. Pete Buchholz
    March 6, 2010 at 1:23 am

    1) I’m not convinced that heterodontosaurids are the most basal
    ornithischians as Butler find them. I think it may be interesting to
    compare the position found by Butler with that found by Xu et al
    (Yinlong paper), as just outside of Marginocephalia with an early
    origin for Cerapoda.

    2) When I run Mateus et al’s matrix in TNT, I get a different topology
    than that depicted in the tree you posted, with the Tuojiangosaurus +
    Paranthodon group as basal stegosaurids. The topology of the 50% majority rule consensus tree is (Ankylosauria (Gigantspinosaurus ((Huayangosaurus + Chungkingosaurus) ((Tuojiangosaurus + Paranthodon) (Kentrosaurus ( Loricatosaurus ((Dacentrurus + Miragaia) (S. armatus + S. homheni + S. mjosi)))))))).

    3) There is a published phylogeny of psittacosaurs, Averianov et al
    2006 in JSP. I don’t buy it personally, but it’s out there and
    published. The topology when I run their matrix is a single MPT (Neoceratopsia ((P. sibiricus + P. sinensis) ((P. ordosensis + P. neimongoliensis) (New Yixian species (P. mazongshanensis + P. xinjiangensis) (P. meileyingensis + P. mongoliensis))))). They came up with a similar topology, but more trees for some reason.

    4) What’s included in Rhabdodontidae besides Rhabdodon if Zalmoxes is
    much higher in the tree? And also, why is Zalmoxes much higher in the tree?

    5) In the original description of Oryctodromeus, Varricchio et al find
    it to be close to Zephyrosaurus and Orodromeus. The other taxa listed
    under ornithopods….. Draconyx is probably close to Camptosauridae,
    but I’m not convinced it’s not a chimera, and Gongbusaurus and
    Xiaosaurus are Ornithischia indet.

  19. John Dziak
    March 6, 2010 at 1:20 pm

    If it’s any help, Colbert (1964) argued for Podokesaurus holyokensis as a species within the genus Coelophysis but not the same species as Coelophysis bauri. Of course this isn’t a cladistic analysis, just a verbal argument.
    http://digitallibrary.amnh.org/dspace/bitstream/2246/3350/1/N2168.pdf

  20. 220mya
    March 6, 2010 at 11:38 pm

    There are significant problems with Xu et al’s analysis. Plus, Butler’s is more comprehensive in terms of both taxa and characters – its probably best to go with Butler’s analyses. Plus, as someone who’s spent time with many of the basal ornithischian specimens, and conducted my own phylogenetic analyses, I have to agree with their basal placement. I know of a couple of other upcoming studies that agree with that position too.

    Podokesaurus is probably not diagnostic, but it does appear to be within the coelophysoid zone of the theropod tree.

  21. March 11, 2010 at 1:44 am

    Robert M. Sullivan :
    What about the ankylosaurid Nodocephalosaurus kirtlandensis which I believe is closer to the Asian Tarchia-Sachania-like ankylosaurids.
    Sullivan, R.M., 1999, Nodocephalosaurus kirtlandensis gen. et sp. nov., a new ankylosaurid dinosaur (Ornithischia: Ankylosauria) from the Upper Cretaceous (Late Campanian) Kirtland Formation of New Mexico: Journal of Vertebrate Paleontology, v. 19, p. 126-139.

    Hi Robert,

    I believe Nodocephalosaurus isn’t included in the cladogram because it does not have limb material preserved, sadly, so it’s not relevant to the Project.

    Cheers,
    Nick

  22. Andy Farke
    March 11, 2010 at 5:31 am

    Nick Gardner :

    Robert M. Sullivan :
    What about the ankylosaurid Nodocephalosaurus kirtlandensis which I believe is closer to the Asian Tarchia-Sachania-like ankylosaurids.
    Sullivan, R.M., 1999, Nodocephalosaurus kirtlandensis gen. et sp. nov., a new ankylosaurid dinosaur (Ornithischia: Ankylosauria) from the Upper Cretaceous (Late Campanian) Kirtland Formation of New Mexico: Journal of Vertebrate Paleontology, v. 19, p. 126-139.

    Hi Robert,

    I believe Nodocephalosaurus isn’t included in the cladogram because it does not have limb material preserved, sadly, so it’s not relevant to the Project.

    Cheers,
    Nick

    Indeed! It’s absence is not an intentional snub. . .all of the limbless taxa are trimmed out of the final version.

  1. March 7, 2010 at 4:27 am

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