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) |