RE: the Eurypoda and Thyreophoroidea fall into

["Michael Mortimer" <mickey_mortimer111@msn.com>]

Lida Xing wrote-

> I want to know what were the Eurypoda and Thyreophoroidea(Thyreophora 
> forms) fall into ?  the "Suborder" ?or "Infraorder" ?

Most biologists recognize that ranks such as "suborder" and "infraorder" are 
meaningless.  There are many posts in the DML Archives dealing with this 
subject.  These thyreophoran clades are a good example of why it's difficult 
to use Linnaean ranks now.  According to the Zoological Record, Ornithischia 
is an order, and Ankylosauria is a suborder.  Below are two possible 
topologies for Thyreophora, and their respective taxonomies.

after Sereno
Ornithischia (order)
Genasauria
Thyreophora
Thyreophoroidea
Eurypoda
Ankylosauria (suborder)

Ornithischia
|--Lesothosaurus
`--Genasauria
  |--Cerapoda
  `--Thyreophora
     |--Scutellosaurus
     `--Thyreophoroidea
        |--Scelidosaurus
        `--Eurypoda
           |--Stegosauria
           `--Ankylosauria

after Carpenter
Ornithischia (order)
Genasauria
Thyreophora
Eurypoda
Ankylosauromorpha
Ankylosauria (suborder)

Ornithischia
|--Lesothosaurus
`--Genasauria
  |--Cerapoda
  `--Thyreophora
     |--Scutellosaurus
     `--Eurypoda
        |--Stegosauria
        `--Ankylosauromorpha
           |--Scelidosaurus
           `--Ankylosauria

In both examples, we have four ranks between order and suborder that would 
need to be named in the Linnaean system.  And once we place taxa like 
Bienosaurus, Tatisaurus, Emausaurus and others in the topology, we may need 
even more.  It's best just to not use ranks.

Mickey Mortimer

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