Classification diagrams

The ASCII cladograms on this page, painstakingly crafted in a monospaced font, are intended to serve as "road maps" for visualizing the trees for the various sheets of The Compact Thescelosaurus. Only clades that are used in the sheets are used here (with a couple of exceptions). A clade preceded by a question mark has uncertain placement. For example, Megaraptora shows up either within Carcharodontosauria or within Coelurosauria, so I've placed it with a question mark at the last place those two lineages meet (Avetheropoda). Without the genera that go between named clades, these are simply frameworks (for example, Euhelopodidae and Titanosauria are not sister groups, they just end up looking that way when genera are cleared out). Generally clades that are sister groups or in polytomies are handled alphabetically or in the traditional "we've always put Saurischia before Ornithischia" way (and how was it decided that "we do Theropoda first, then Sauropodomorpha, then finally Ornithischia", anyway?). I've omitted a number of clades, particularly those close to genus level, as not particularly helpful and subject to excessive instability, although for some reason I ignored this policy with the dromaeosaurids, ceratopsids, and hadrosaurids. I figure that one doesn't need to name every possible clade, and those which are named ought to "do something".

The trees are fairly "consensus", since I've gotten more hesitant over the years about changing things after the latest publication, and I don't have particularly strong opinions about the classification of non-dinosaurian groups. The main areas I disagree with others are in Ornithischia, where I haven't entirely bought the removal of all hypsilophodontish-types out of Ornithopoda. (Even if I did, I don't see the point in calling the leftovers Ornithopoda. That remainder *has* a well-used historical name: Iguanodontia. Just label it Iguanodontia, send Ornithopoda to the Home for Outdated Groups, and call it a day.)

Concerning the "nexus of basal coelurosaurs" versus Coelurosauria: The "nexus" is for reasonably well-known taxa that belong somewhere between the base of Coelurosauria and Tyrannoraptora, or between Tyrannosauroidea and Maniraptoriformes. Taxa listed at Coelurosauria are generally poorly known coelurosaurians, some of which are dubious and can't be placed any farther, others of which need a bit more study or material to place, and/or are there because of the "lowest position that can describe two options" thing.

Basal Avemetatarsalia

   │ └Dracohors
   │  └┬Silesauridae
   │   └Dinosauria


  ││ ├Coelophysoidea
  ││ └┬Dilophosaur-grade neotheropods
  ││  └Averostra
  ││   ├Ceratosauria
  ││   │├Ceratosauridae
  ││   │└Abelisauroidea
  ││   │ ├Noasauridae
  ││   │ │├Elaphrosaurinae
  ││   │ │└Noasaurinae
  ││   │ └Abelisauridae
  ││   └Tetanurae
  ││    ├Megalosauroidea
  ││    │├Piatnitzkysauridae
  ││    │└┬Megalosauridae
  ││    │ └Spinosauridae
  ││    └Avetheropoda
  ││     │?Megaraptora
  ││     ├Carnosauria
  ││     │├Metriacanthosauridae
  ││     │└┬Allosauridae
  ││     │ └Carcharodontosauria
  ││     │  ├Carcharodontosauridae
  ││     │  └Neovenatoridae
  ││     └Coelurosauria
  ││      ├"Nexus of basal coelurosaurs"
  ││      └Tyrannoraptora
  ││       ├Tyrannosauroidea
  ││       │├Proceratosauridae
  ││       │└Tyrannosauridae
  ││       └┬Compsognathidae
  ││        └Maniraptoriformes
  ││         ├Ornithomimosauria
  ││         │└Ornithomimidae
  ││         └Maniraptora
  ││          ├Alvarezsauroidea

  ││          │└Alvarezsauridae
  ││          └┬Therizinosauria
  ││           │└Therizinosauroidea
  ││           │ └Therizinosauridae
  ││           └┬Oviraptorosauria
  ││            Caudipteridae
  ││            │└Caenagnathoidea
  ││            │ ├Caenagnathidae
  ││            │ └Oviraptoridae
  ││            └Paraves
  ││             │?Scansoriopterygidae
  ││             └┬Deinonychosauria
  │              ├Archaeopterygidae
  ││              │Dromaeosauridae
  ││              │└┬Microraptora
  ││              │ └Eudromaeosauria
  ││              Troodontidae
  ││              └Unenlagiidae
  ││              ├Halszkaraptorinae
  ││              └Unenlagiinae
  ││              └>Avialae 
  │ └┬Unaysauridae
  │  └Plateosauria
  │   └Massopoda
  │    └┬Riojasauridae
  │     └┬Massospondylidae
  │      └Sauropodiformes
  │       └Sauropoda
  │        └┬Lessemsauridae
  │         └Gravisauria
  │          └Eusauropoda
  │           └┬Turiasauria
  │            └Neosauropoda

  │             Diplodocoidea
  │              └Titanosauriformes
  │               ├Brachiosauridae
  │               └Somphospondyli
  │                ├Euhelopodidae
  │                └Titanosauria
    │ ├Stegosauria
    │ │├Huayangosauridae
    │ │└Stegosauridae
    │ └Ankylosauria
│  ├Parankylosauria
    │   └Ankylosauridae
    │    └Ankylosaurinae
      │ ├Chaoyangsauridae
      │ └Neoceratopsia
      │  └┬Leptoceratopsidae
      │   └┬Protoceratopsidae
      │    └Ceratopsoidea
      │     └Ceratopsidae
      │      ├Centrosaurinae
      │      │└┬Nasutoceratopsini
      │      │ └┬Centrosaurini
      │      │  └Pachyrhinosaurini
      │      └Chasmosaurinae
                  │ └┬Kritosaurini
                  │  └┬Edmontosaurini
                  │   └Saurolophini


           │ └Ctenochasmatoidea
           │  ├Gallodactylidae
           │  └Ctenochasmatidae
             │ ├Pteranodontidae
             │ ┬Lonchodectidae
             │  ┬Lanceodontia
│   ┬Istiodactyliformes
│    Istiodactylidae
             │    └Mimodactylidae
             │    ┬Targaryendraconia
             │     └Anhangueria
             │      ├Boreopteridae
             │      └Anhangueridae



(that didn't take too long!)

Sauropterygia and friends

The catch here is I haven't committed to the placements of the placodonts and some other oddballs. (Incidentally, one reason I split the sauropterygians into basal forms and plesiosaurs was because otherwise I'd have needed to include several columns for Sauropterygia, Eosauropterygia, Pistosauroidea, and Pistosauria in the classification.)

  │ └┬Placodontia
  │  └┬Placodontoidea
  │   └Cymatodontoidea
  │    └┬Cymatodontida
  │     │└Henodontidae
  │     └Placochelyida
  │      └Placochelyidae
  │ Saurosphargidae
    ││ └Simosauridae
    │ └┬Keichousauridae
    │  └Pachypleurosauridae
             │ └Styxosaurinae




    │ │└Tylosaurinae
    │ └┬Tethysaurinae
    │  └Yaguarosaurinae





Triassic Pseudosuchia

Aetosauriformes (see above)

No comments:

Post a Comment