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
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