View Details:  Prev Record    Next Record
Clade
Subclade

Taxon
Taxon
Sauropodomorpha
Nominal Author
Huene 1932
2nd Nominal Author
Taxon Status ACTIVE
Comments

Sauropodomorpha was coined as both a node- and stem-based taxon by Salgado et al. (1997) and Upchurch (1997), respectively. Sereno (1998) used a node-based definition, because it allowed the formation of a node-stem triplet identifying a major basal division of Sauropodomorpha into Prosauropoda and Sauropoda. The monophyly of Prosauropoda (even its core and best known genera Plateosaurus, Massospondylus, Lufengosaurus, Yunnanosaurus, Riojasaurus) has been challenged. Mussaurus patagonicus (Pol and Powell 2005), for example, clearly shares several cranial synapomorphies with sauropods, while retaining the twisted manual digit I and other derived features common to basal sauropodomorphs. At the very least, this has weakened the character support that had united core prosauropods.

There is also the remote possbility that sauropodomorphs and ornithischians are sister taxa to the exclusion of Theropoda. Although not supported in recent analyses, character support for Saurischia is not overwhelming (Serreno 1999, Langer 2004) no matter where one places basal taxa such as Eoraptor and Herrerasaurus. the discovery of more complete early taxa such as Silesaurus may shift the balance to favor another arrangement.

The active definition for Sauropodomorpha, thus, is a first-order revision of the stem-based definition in Upchurch (1997) and Galton and Upchurch (2004) but employs more deeply nested specifiers. It also includes an an deeply nested specifier within Ornithischia to ensure stability of taxonomic content should Sauropodomorpha and Ornithischia resolve as sister taxa. In this way, the taxonomic content of this clade (like Ornithisichia and Saurischia) is stabilized under any plausible arrangement of basal taxa.

Potential Synonomy

Active Phylogenetic Definition
Active Definition
The most inclusive clade containing Saltasaurus loricatus Bonaparte and Powell 1980 but not Passer domesticus (Linnaeus 1758), Triceratops horridus Marsh 1889.
Shorthand
> Saltasaurus loricatus but not Passer domesticus, Triceratops horridus.
Definitional Author
Sereno 2005
Definition Status checked
Definition Type STEM
Node-Stem Triplet NO
Other Triplet Taxa
Specifiers
Specifier(s) A
Saltasaurus loricatus
Specifier(s) B
Specifier(s) C
Passer domesticus, Triceratops horridus
Qualifiers
+Taxon
-Taxon
Datum
Taxonomic Content
Publication Year Unknown
Unknown
Unknown
1997

Inactive Taxon Status
Rejection Criteria
Critique
 

Definitional History #1
Earliest Record
The clade including the most recent common ancestor of Prosauropoda and Sauropoda and all of its descendants.
Latest Record
Salgado et al. 1997:6
Range (My)
Range (My)
Prosauropoda, Sauropoda
Range (My)

Definitional History #2
Earliest Record
Sauropoda, Prosauropoda, and all saurischians closer to them than to birds.
Latest Record
Upchurch 1997:658
Range (My)
Range (My)
Sauropoda, Prosauropoda, birds
Range (My)

Definitional History #3
Earliest Record
Plateosaurus, Saltasaurus, their most recent common ancestor and all descendants.
Latest Record
Sereno 1998:63
Range (My)
Range (My)
Plateosaurus, Saltasaurus
Range (My)

Definitional History #4
Earliest Record
All taxa more closely related to Saltasaurus than to Theropoda.
Latest Record
Galton and Upchurch 2004:249
Range (My)
Range (My)
Saltasaurus, Theropoda
Range (My)

Definitional History #5
Earliest Record
Latest Record
Range (My)
Range (My)
Range (My)

Definitional History #6
Earliest Record
Latest Record
Range (My)
Range (My)
Range (My)

Definitional History #7
Earliest Record
Latest Record
Range (My)
Range (My)
Range (My)

Definitional History #8
Earliest Record
Latest Record
Range (My)
Range (My)
Range (My)

Definitional History #9
Earliest Record
Latest Record
Range (My)
Range (My)
Range (My)

Definitional History #10
Earliest Record
Latest Record
Range (My)
Range (My)
Range (My)